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SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY NUMBER 12
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SMITHSONIAN CONTRIBUTIONS TO
PALEOBIOLOGY
NUMBER 12
Richard H. Benson The Bradley a Problem,
With Descriptions of
Two New Psychrospheric
Ostracode Genera,
Agrenocythere and
Poseidonamicus
(Ostracoda: Crustacea)
ISSUED
OCT s e w ?
SMITHSONIAN INSTITUTION PRESS
CITY OF WASHINGTON
1972
A B S T R A C T
Benson, Richard H. The Bradley a Problem, with Descriptions of Two New Psychrospheric
Ostracode Genera, Agrenocythere and Poseidonamicus (Ostracoda:
Crustacea). Smithsonian Contributions to Paleobiology, number 12, 138 pages, 67
figures, 14 plates, 4 table. 1972.—The "Bradleya problem" is concerned with the
discovery and definition of a group of fossil and Recent reticulate ostracodes, several
of which are common to Cenozoic deep-sea sediments in many parts of the world
ocean floor. These species have often been misunderstood and taxonomically confused
with genera characteristic of the study of shallow-water forms. The present
study attempts to resolve some of these misunderstandings by designation of several
important type-specimens, description of new evidence and the proposal of a new
classification based on the concept of the evolution of a reticulum in response to
environmental change. A method of pattern analysis is used to define elements of
the reticulum subject to evolutionary change.
Over 40 reticulate species, which would have at one time been regarded as Bradleya,
were examined; only 14 of these are assigned and belong to Bradleya. Two new
genera, Agrenocythere and Poseidonamicus, are described for the reception of the
others, and these are placed in the new subfamily, Bradleyinae, and placed with
Thaerocytherinae Hazel in a new family (Thaerocytheridae Hazel). Twenty-seven
of these species are described, including Bradleya arata (Brady), B. dictyon (Brady),
B. normani (Brady), Agrenocythere radula (Brady), A. pliocenica (Sequenza), and
A. hazelae (van den Bold). The diagnostic characteristics of the related genera
Cletocythereis, Oertliella, Jugosocythereis, and Hermanites are discussed and
illustrated.
It is concluded that the psychrospheric species Agrenocythere pliocenica, which
has been reported from outcrops in Italy and a long core from the Tyrrhenian Sea
floor, is most closely related to A. hazelae, which became geographically widespread
during the Miocene. Bradleya, Jugosocythereis, Agrenocythere, and Cletocythereis,
now genera in separate families, are all thought to have been derived from a common
stock of Cretaceous age.
Official publication date is handstamped in a limited number of initial copies and is recorded
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Contents
Page
Introduction j
The Bradleya Problem 2
Methods 4
Illustration 4
Pattern analysis 4
Causes of patterns 5
Pore conuli distribution 6
Architectural form 7
The meaning of characters 8
Material Studied 8
Acknowledgments 9
Conceptual Development of the Genus Bradleya 10
Morphologic Trends in Bradleya and Poseidonamicus 13
Origins of Agrenocythere, Bradleya, and Poseidonamicus 17
Distribution and Evolution of Agrenocythere 23
Systematics 27
Family Thaerocytheridae Hazel, 1967 27
Subfamily Bradleyinae, new subfamily 28
Genus Bradleya Hornibrook, 1952 28
Bradleya arata (Brady, 1880) 33
Bradleya dictyon (Brady, 1880) 34
Bradleya normani (Brady, 1865) 38
Bradleya albatrossia, new species 39
Bradleya japonica, new species 40
Bradleya andamanae, new species 40
Bradleya nuda, new species 41
Bradleya paranuda, new species 42
Bradleya mckenziei, new species 42
Bradleya? telisaensis (Le Roy, 1939) 42
Subgenus Quasibradleya, new subgenus 43
Bradleya (Quasibradleya) dictyonites, new species 44
Bradleya (Quasibradleya) pro dictyonites, new species 45
Bradleya (Quasibradleya) paradictyonites, new species 45
Bradleya (Quasibradleya) plicocarinata, new species 46
Genus Poseidonamicus, new genus 46
Poseidonamicus major, new species 52
Poseidonamicus minor, new species 53
Poseidonamicus pintoi, new species 53
Poseidonamicus nudus, new species 54
Family Trachyleberididae Sylvester-Bradley, 1948 55
Subfamily Trachyleberidinae Sylvester-Bradley, 1948 55
Genus Agrenocythere, new genus 58
Agrenocythere spinosa, new species 64
Agrenocythere hazelae (van den Bold, 1946) 64
Agrenocythere americana, new species 73
Agrenocythere radula (Brady, 1880) 74
Agrenocythere pliocenica (Sequenza, 1880) 77
Agrenocythere gosnoldia, new species 78
Agrenocythere antiquata, new species 84
Agrenocythere? cadoti, new species 86
iii
IV SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
Page
Genus Oertliella Pokorny, 1964 89
Oertliella ducassae, new species 95
Literature Cited 97
Appendix: Distribution Data 101
Index 138
Richard H. Benson The Bradleya Problem,
With Descriptions of
Two New Psychrospheric
Ostracode Genera,
Agrenocythere and
Poseidonamicus
(Ostracode: Crustacea)
Introduction
During the study of fossil and living ostracodes of the
deep-sea (psychrosphere), I have been particularly
impressed with the reticulate form that Brady (1880)
originally described from Indonesia as Cythere radula.
This species, which he easily differentiated (on one
specimen, in fact) from the deep-sea form Cythere
dictyon Brady, is similar to a Neogene species originally
described from Italy as Cythereis pliocenica by
Sequenza (actually the same year, 1880, as the publication
of the Challenger Report). Several workers,
including Ruggieri (1962) and van den Bold
(1968b), have puzzled over the relationships of these
three species and a fourth, Cythereis hazelae, originally
described by van den Bold (1946) from "deepwater
sediments" of the upper Paleogene and lower
Neogene of the Caribbean region. The generic concept
of Bradleya (conceived by Hornibrook in 1952
for Cythere arata Brady (1880) and several other species,
including C. dictyon) has been considered for
these four species and several more. Confusion from
several sources has resulted in what van den Bold
Richard H. Benson, Department of Paleobiology, National
Museum of Natural History, Smithsonian Institution, Washington,
D.C. 20560.
(1968b) termed the "Bradleya problem." Unraveling
the complex relationships of these four species (and
twenty more new ones) and the study of patterns in
the reticulate carapace ornament and the muscle
scars are the subjects of this report.
During the course of the present study, it was noted
that basic reticular patterns are common to several
genera and that modifications in these patterns can be
traced to determine phyletic relationships. Among
these genera, the trachyleberids Oertliella (Pokorny
1964a), Cletocythereis (Swain 1963), and a new
genus Agrenocythere, can be shown to have a common
origin. Another group, including the thaerocytherids
Bradleya (Hornibrook 1952) and Jugosocythereis
(Puri 1957), has yet another pattern. A third
group, of which I have only studied part, includes
Hermanites (Puri 1954), Hornibrookella (Moos
1965), and Limburgina (Deroo 1966) and has some
of the characteristics of both preceding groups. Cletocythereis,
whose V-shaped frontal scar (as seen in the
type-specimen) is slightly divided, is seen as an example
of the tendency of the frontal scar to divide in
separate phyletic lines. The lack of a developmental
theory including the evolution of the reticulum as well
as muscle-scar patterns, has led to confusion about
generic assignment of several important species. I
1
SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
hope the following discussion will shed some light on
these problems and also contribute to the formulation
of such a theory.
In 1960, Ruggieri identified "Hermanites?" hazelae
(previously "Cythereis," also "Trachyleberis," and
later "Bradleya" hazelae) from the Miocene of Sicily.
For several years the full significance of this discovery
was only appreciated by Ruggieri, who in several
places (unfortunately for some of us, in Italian) was
pointing out the possible deep-sea aspect of several
Italian ostracodes. The properties of ornateness and
large size are characteristic attributes of "deep-sea"
ostracodes, and Ruggieri was quick to recognize that
these species {hazelae and pliocenica) were different
from most of the other forms found in southern
Europe. It was not until Ascoli (1969) called attention
to the presence of "Bradleya hazelae" (now called
Agrenocythere antiquata Benson, new species) in the
Paleocene and Eocene of northern Italy that one possible
link in the solution to the relationship of Cythere
radula and Cythereis pliocenica appeared. Another
link comes from the study of Recent and fossil deepsea
species in the Atlantic, including specimens from
the Tertiary of the Caribbean (supplied to me by
W. A. van den Bold) and those from the cores of the
Deep Sea Drilling Project.
Coincidentally with the discovery by Ascoli and my
examination of deep-sea (psychrospheric) species, I
was fortunate to examine and photograph that part of
Brady's Challenger collection reposited in the British
Museum. With the help of J. P. Harding and H.S.
Puri, I was able to establish the identity of those
specimens that are most likely to have been considered
by Brady as representative of some of his original
species concepts (herein designated as lectotypes).
These include the types of Bradleya arata and Cletocythereis
rastromarginata, as well as Bradleya dictyon
and Agrenocythere radula.
In pursuit of an explanation of both the taxonomic
and biogeographic relationships of the two genera
Bradleya and Agrenocythere, new genus, I discovered
a third genus Poseidonamicus, whose form was obscured
in Brady's species concepts. This new genus
will be described, and some of its species introduced,
as they seem relevant to the general discussion.
Implicit in the study of the relationships among the
species of these genera is the establishment of the
likelihood of genetic continuity across the shortest
geographic distance possible; a coincidence of taxonomic
and paleobiogeogaphic distance. Such is not easily
obtained considering the scale of the distribution
of the evidence I had available, and the tectonic
changes that must have occurred during the tenure of
the taxa involved. Because of the importance of
Agrenocythere pliocenica (Sequenza) as a prominent
member of the fossil psychrospheric ostracode fauna
in the Mediterranean, special attention is given to this
form. Demonstration of its relationship to Atlantic
deep-sea predecessors has a great bearing on the tectonic
and hydrographic evolution of the Mediterranean
from Tethys (Benson and Sylvester-Bradley
1971; Benson, n.d.b.). Unfortunately, not all of the
pieces of this evolutionary puzzle are available, calling
for a careful study of present evidence.
The Bradleya Problem
There have evolved, one from the other, two "problems"
concerning the developmental explanation and
classification of several of the important reticulate,
deep-water ostracode species. One of these is the
"Bradleya problem" (referred to first by van den Bold
1968b: 67). The other is related to finding the best
of possible explanations of genetic continuity among
species of the genus Agrenocythere, now separated by
fragments of continents and hydrographic barriers.
Briefly, the "Bradleya problem" is concerned and
originated with Brady's study (1880) of several very
unusual reticulate ostracode species from the Challenger
collection. Some of these species are now
known to be restricted to the psychrosphere, rarely to
be seen as fossils on the continents, and others simply
were from remote parts of the world. Some had remains
whose detailed morphology has not been easy
to examine. A few of the psychrospheric species, such
as Cythere dictyon, have been reported from widely
separate parts of the world. Yet their description has
been vague and their taxonomy subsequently confused.
In the case of Cythere dictyon, almost every identification
of classification has been appended by remarks
questioning its proper status. In 1952, Hornibrook
established the genus Bradleya to receive two of
Brady's species, including Cythere dictyon and using
Cythere arata Brady as the type. The genus was conceived
using morphologic criteria that were advanced
for that time; yet the concept of Bradleya became
NUMBER 12
almost as vague in application as that of Cythere
dictyon. Also, because of the lack of other available
genera or generic concepts for related or at least morphologically
similar forms, I, as well as others, enlarged
Hornibrook's original concept to the point of
meaninglessness.
It is necessary, therefore, to return to a very conservative
position in the analysis of this genus, and
with more data than has been available in the past, to
attempt to follow the gradual morphological changes
that have occurred among the originally described
and closely related species. It soon becomes evident
that "Bradleya" is a much different, and even larger
genus, from what was previously suggested. It is one
with considerable variation in form among its constituent
species. Also, as others have suspected, some species
that have been assigned to "Bradleya" are not
Bradleya. Some in fact belong to another family-level
taxon.
Concerning the problem of distribution (the
"Agrenocythere problem") we have stressed (Benson
and Sylvester-Bradley 1971; Benson, n.d.b.) that the
presence of psychrospheric ostracodes in the fossil record
of southern Europe, presently far removed from
the deep sea, requires some radical alterations in theories
regarding the nature of the barriers that were
once supposed to separate Tethys from the rest of the
world ocean. "Bradleya" pliocenica (Seguenza) (the
combination first used by Ruggieri 1962) found in the
Pliocene of Italy and in the floor of the Tyrrhenian
Sea, was considered to be among the Tethyan psychrospheric
ostracodes that occupy this "displaced"
geographic position. Its similarity to "Cythere" radula
seems evident, however remote geographically. The
regularity of reticular pattern and V-shaped muscle
scar are the same or very similar in each. Yet there
are subtle differences. The sculpture around the muscle
scar node, the castrum, is not the same. At the
time of the original study other candidates of possible
close relationship from the nearby open Atlantic were
missing. I will show in the present report that the
species pliocenica or radula are not Bradleya, but are
related, although not closely, and belong to another
important psychrospheric ostracode genus, and that
pliocenica, now found more than 1000 miles from the
ocean, is related to an important Atlantic Neogene
species.
The reticulate genus Bradleya was first described in
1952 by Hornibrook to accept nine species of Cenozoic
and Recent ostracodes from New Zealand. Principal
among these were Cythere arata (designated
type-species) and C. dictyon, both species described
originally by Brady (1880). Brady reported Cythere
arata from the Recent of the Tasman Sea. C. dictyon
was found in many regions of the world ocean floor.
The other species treated by Hornibrook were local
fossil forms that were in general similar to Bradleya
arata, but which also included the Paleogene species,
B. semivera Hornibrook. This later species is more tapered,
even caudate, and less rectangular in shape
with a reticular pattern like that of Cythere radula
Brady, 1880, and differs in other respects from Bradleya
arata. In particular it has a V-shaped frontal
scar compared to the simple paired frontal scars of
the Bradleya arata—Bradleya dictyon complex. The
original breadth of generic concept by Hornibrook,
which included such different species as B. semivera,
has caused others (Ruggieri 1960, Hazel 1967) to
have concern about the significance of the difference
in muscle-scar pattern in preference to the overall
similarity of size and reticulation shared by this group.
This problem was further clouded by the fact that
Brady had included several related, yet dissimilar
forms in C. dictyon, the second most important species
of Hornibrook's new genus. Brady readily conceded
that he had included several varieties of form
within this species; however, he seems convinced (by
his discussion) that differences in surface ornament
can be explained by simple "exaggeration of characters"
due to the effects of "senility." As will be shown
later, the specimens, whose assignment to C. dictyon
Brady did doubt, are probably closely related to C.
normani (which he described from the North Atlantic
in 1865, but which I believe he misidentified at least
once, Plate 26: figure 4a, b in the Challenger report),
and to C. viminea, also described in the Challenger
report.
Brady (1880:101) remarked on the general similarity
of Cythere dictyon to Cythere arata, which he
suggested differs in the "style of ornament." The latter
species is relatively smooth and devoid of apparent
reticulation, which is characteristic of the former species.
I hope to demonstrate that through examination
of the finer surface features of both forms, and
through the development of a concept about progression
in a morphotypic series within the pattern of the
reticulum, that these differences are not of primary
importance on the generic level. Cythere dictyon
SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
(that is, those forms conspecific with the lectoholotype)
and C. arata (type-species of Bradleya Hornibrook,
1952) are indeed both species of Bradleya.
That van Morkhoven (1963) questioned the assignment
of C. dictyon to Bradleya is based on his assumption
that Hornibrook had selected the correct form as
being C. dictyon. This, as we will see, was not a valid
assumption. Hornibrook's misidentification of Cythere
dictyon was not without just cause. Matters were complicated
by the long delay in selecting a lectoholotype
from among Brady's specimens to represent C. dictyon.
He was more fortunate in the identification of
C. arata. The specimen (BM 80.38.52a) of Bradleya
arata (Brady) in the British Museum seems to me
without doubt assignable to the description and illustration
of Hornibrook (1952, pi. 6: fig. 80), and to
the same population from which a specimen was
taken for illustration in this report (Plate 11: figures
16,17).
In summary, I hope to present evidence that Bradleya
is a thaerocytherid genus, with morphologic aspects
characteristic of a large group of species and
genera (constituted as a new subfamily, the Bradleyinae)
; and that Bradleya dictyon is in general restricted
to deeper waters. Although quite variable,
Bradleya does not contain reticulate forms like C.
viminea Brady (included in the new genus Poseidonamicus,
even though they were mistaken by Brady for
C. dictyon) or C. radula Brady, or a host of others
that have been suggested including those trachyleberid
forms such as "Bradleya" semivera, herein assigned,
at least provisionally, to Agrenocythere. Also
in the present work, I will present evidence that Cythereis
hazelae and Cythereis pliocenica do in fact differ
from those species properly assigned to Bradleya in
"essential nature" (van den Bold, 1968:66) rather
than "degree." The subdued subcentral tubercule of
Bradleya is joined to the anterior margin by a reticular
bridge (typical of other bradleyines as well). The
subcentral tubercule of Bradleya is not developed as a
castrum as in Agrenocythere, the new genus to which
these species are assigned (see p. 58). The reticular,
fossal, and pore conuli patterns of Bradleya are different
than that of either new genera, Agrenocythere or
Poseidonamicus. Above all, the frontal muscle scar of
C. hazelae and C. pliocenica is decidedly trachyleberid
and not thaerocytherid. No matter which specimen
was chosen from among those logically available as
type-specimen of Bradleya dictyon, none would be
similar in "these respects to Bradleya (now Agrenocythere)
hazelae. Removing Agrenocythere hazelae
along with "Bradleya" semivera from Bradleya begins
to substantially reshape the problem around the definition
or a morphotypic series including Bradleya
arata and B. dictyon. Twelve other species are added
to this (o: these) series.
Methods
ILLUSTRATION.—Some aspects of methodology regarding
the collection and illustration of deep-sea ostracodes
were mentioned in a previous report on
Abyssocythere (Benson 1971) and will not be discussed
again here. The usefulness of the stereo-pairs
of Scanning Electron Microscope photographs is by
now self-evident. It would be difficult indeed to analyze
the distribution of pore conuli, so important for
the analyses of Agrenocythere, new genus, in this report,
without this instrument. (This comment is in
rebuttal to one made earlier by me in Neale 1969:
238.) The light photographs were made with the aid
of a back-lighting technique, which allows the silver
nitrate stained specimens to be shown darker than is
often customary, bringing out more depth to the
shape. The several drawings of carapace morphology
attempt to portray the concept of form and in most
instances are not intended to represent a particular
specimen.
PATTERN ANALYSIS.—One of the principal methods
of morphological analysis used in this study is the
creation of a series of progressively more abstract
models of carapace form. By this method, it is possible
to demonstrate the contrast in form that exists among
different but related species. The presence of conservative
patterns of the reticulum and pore conuli distribution
(and to a lesser extent the pattern formed by
the fossae; the fossal pattern) can be shown and compared
with the general changes in shape, size, and
robustness of the rest of the carapace. This process of
analytical reductionism also includes identification
and naming of homologous features, and characterizing
their patterns of distribution in as simplified a
way as possible, in some cases by structural analogy
and in others by graphic substitution.
The first portion of the reductionist process in part
follows the method first described and used by Pokorny
(1969a, b) on specimens from samples in my
collection from the Galapagos Islands, and also later
employed by Liebau (1969; his "KoordinaNUMBER
12
tensystems"; see also Anderson 1967). By this method,
particular fossae and pore conuli were to be identified
(fossal and pore conular patterns) using an arbitrary
system of codification developed principally by Liebau
for his study of Oertliella. In general this method,
which identifies aligned fossae in parallel series, was
found to be satisfactory, except that the enumerative
code of specific features can be difficult to remember,
and comparison of the reticular patterns (using the
letter-number combinations) among many different
forms can be confusing. In particular, I find that this
method tends to focus on the wrong aspect of reticulation;
that is the fossae rather than the ridges or
muri. In the diagrams of both Pokorny and Liebau, it
is what is not present in the reticulum that is emphasized.
I have named some of the more important architectural
features of the reticulum, using the mnemonic
device of architectural or structural analogs, in the
case of Agrenocythere, new genus, analogs from medieval
fortifications. Mapping the distributions of pore
conuli over the reticular field represents a separate
problem. This nomenclatural system is defined and
explained on pages 6, 7 and under the sections
devoted to the general morphology of Bradleya and
the new genus Agrenocythere. In the analyses of
Bradleya and Poseidonamicus, new genus, whose reticular
patterns are simpler, the individual fossae are
not identified for purposes of this study, but they are
zoned for comparison. In comparing many forms related
to Agrenocythere, a color code system was used
for the patterns of fossae which was superimposed on
reticular silhouettes (Plates 5 and 6). A constellar
framework system shown on the acetate overlays represents
the distribution of pore conuli. As can be seen,
superposition and comparison of these patterns exaggerates
the differences between the various forms.
Inspection of the constellar patterns by themselves
emphasizes the similarity of the same forms. The
effectiveness of this method can be demonstrated by
comparing the degrees of allometric distortion shown
by the male relative to the female of Agrenocythere
Jnlocenica, and with the interspecific variation among
the other examples of female left valves.
Reticular silhouettes represent a first order reduction
of the pattern of the reticulum. In mapping the
muri some information about the form is lost (especially
the vertical relief of the muri, which must be
brought out through other means), but the original
form of the species is still identifiable. Identification
of homologous fossae (through study of fossal patterns)
among various different forms is facilitated by
the silhouettes (reticular patterns), which emphasize
the overall pattern of reticulation and decrease differences
in overall shape (but not outline). Recognition
of combinations of mutually adjacent sides among contiguous
fossae helps to resolve difficulties in identification
of the same fossae within the more rapidly
changing portions of the fossal patterns taken in series.
The greatest difficulty may come as some fossae
merge or are excluded by other fossae. This problem
apparently gave Liebau (1969) difficulty in his
"Koordinatensystem," as is reflected in the break in
alphabetic sequence of his code with contiguous
placement of the fossae. The logic of the present
method does not entirely resolve this problem, but it
does at least recognize it. Fortunately, many intermediate
forms exist that have partially formed muri indicating
fossal division, or combination, in progress.
These can be seen clearly in Bradleya and Poseidonamicus,
new genus. Their presence gives some insight
into the course of pattern change as fossae merge and
lose their individual identity.
One would assume that eventual conversion of this
reduced information to computer schemes could account
for the tendency of disappearance or multiplication
of the fossae in certain sectors of the fossal
patterns. This leads to the next order of mathematical
abstraction (permutation, from enumeration) and
might be used to show degrees of difference or similarity
among species in a quantitative manner. This
has only been done by inspection with the present
display of patterns. I suggest that this present system,
which is primarily graphic and in part geometric, is a
necessary step in transformation toward a proper
quantitative analysis (of which the most difficult part
is deciding which changes are important). I would
suspect that an information function might be appropriate
to describe the association between fossae and
their repetitive order within the patterns. Yet, as
mentioned earlier, I am concerned that attention
given only to the several series of fossae removes from
analysis the actual subject on which selection operated.
CAUSES OF PATTERNS.—The interpretation of the
cause of the reticular patterns is germane to the present
study insofar that it is assumed, here at least, that
its development among different species is genetically
SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
FIGURE 1.—Sample localities where specimens of Bradleya were found. Dots indicate Recent localities;
circles indicate fossil localities; and solid triangles indicate DSDP Hole locations. Data
for the locations are given in Table 1.
controlled. That is to say, natural selection is dominantly
responsible for the change in emphasis of the
muri between forms within a more conservative
framework responsible for the fossal pattern. This
change is not simply some kind of somatic adjustment
in the distribution of strengthening elements of the
shell structure. An alternate argument might claim
that the similarity among various reticular or fossal
patterns is caused by convergence arising from ecological
pressure on individuals within their own life span.
Mechanical compensation among carapace forming
cells to adjust for overall changes in shape might also
be given as the cause for the arrangement or rearrangement
of the patterns. Both genetic and nongenetic
causes are possible, I suppose. Yet the consistency
of the patterns in a given sample is striking, and
the conservatism, even among different genera derived
through other analyses, is most impressive. Presently
I doubt that ecophenotypic variation within a
single reproducing population is a significant factor in
deep-sea species.
PORE CONULI DISTRIBUTION.—The value of recognizing
the individual pore conuli lies in their status as
fixed reference points on the carapace. They seem to
be more conservative in number and distribution than
even the elements of the reticular or fossal patterns.
The importance of having reference points among a
complex array of elements composing the surface ornament
can be readily appreciated. Consistency of
relative position among reference points is required
for accurate estimation of changes in phyletic allometry
within a taxal series. The production of a grid
NUMBER 12
FIGURE 2.—Sample localities where specimens of Poseidonamicus, new genus, were found. Dots
indicate Recent localities; circles indicate fossil localities; solid triangles indicate DSDP Hole
locations. Data for the locations are given in Table 2.
composed of lines drawn between these points (the
purest geometric form of the reductionist abstraction)
allows comparison of the distortion of form that results
from dimorphism or phyletic adjustments of different
adaptive modes. For example, it now can be
shown that a basic difference in shape exists between
Cythereis (Plate 5: figure 2), whose reticulum in the
central lateral regions of the carapace is compressed
relative to enlarged marginal areas, and Oertliella
(Plate 5: figures 5, 6), whose shape is formed by a
more equitable distribution of many of the same carapace
elements.
ARCHITECTURAL FORM.—With the Scanning Electron
Microscope it is possible to magnify portions of
the complex carapace with great clarity, and even in
three dimensions. It is this last aspect of the instrument's
ability that impresses the observer with the intricate
and integrated architecture of carapace form. I
have discussed this subject elsewhere (Benson, n.d.a).
It is soon obvious that carapace architecture, or the
actual form solution of the problems of metabolistic
limits in shell formation and strength, is of paramount
importance in the success of some kinds of ostracode
shapes over others. To acknowledge this fact, I have
tried to emphasize the architectural forms, through
identification and analogy, in the discussions of the
carapace morphology of the various species diagnosed
in this report. This, at least in the beginning, supplements
the various pattern analyses and, to some extent,
compensates for the loss of the three dimensional
aspect (vividly shown in photographs) that is lost in
diagrams of patterns.
SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
THE MEANING OF CHARACTERS.—Lastly, in consideration
of the classification of an evolving taxon into
discrete categories, it is necessary to recognize that the
character group used for dieir definition must be of
sufficient complexity and flexibility (present or absent
in prograding groups) to accurately reflect this evolution.
This multistage aspect allows for the characterization
of evolution by shifting matrices of attributes
and is best derived from integrated groups of characters
and not reliance on single characters (polythetic
verus monothetic classification). I believe this is one
of the strongest arguments for pattern analysis as is
attempted in the present work.
Material Studied
Psychrospheric ostracodes, like many deep-sea animals,
are relatively rare compared to those living on
the shelf. I have attempted in every sample studied to
obtain 300 specimens. Many times this was not possible.
Often obtaining 300 specimens required washing
several, even tens of liters of mud sample. Even so, in
a given sample a single species may only be represented
by a few specimens.
Ninety-nine samples yielded specimens of the various
species of Bradleya, and 116 samples yielded
specimens of species of Poseidonamicus, new genus.
FIGURE 3.—Sample localities where specimens of Agrenocythere, new genus, were found. The
numbers correspond to those given as map designations in Table 3. The species (designated byletters)
are as follows: (A) Agrenocythere radula (Brady, 1880); (B) A. americana, new
species; (c) A. gosnoldia, new species; (D) A. antiquata, new species; (E, F, G, H, I)
geographical and temporal variants of A. hazelae (van den Bold, 1946) ; (j) A. pliocenica (Seguenza,
1880); (K) A. spinosa, new species; (L) Oertliella reticulata (Kafka, 1886);
(M) Cythereis ornatissima Reuss, 1846; (N) Oertliella ducassae, new species; (o)Oertliella
aculeata (Bosquet, 1852) ; ( P ) Agrenocythere? cadoti, new species. A more detailed map of the
distribution of sampling localities in the Mozambique Channel area is given in Figure 30.
NUMBER 12
These are listed with their locations in Tables 1 and 2
and in Figures 1 and 2. The specimens of these taxa
were much more abundant than those of Agrenocythere,
new genus. I have not counted them for the
present study, but I would judge their number to
exceed several thousand. Because the variation within
the groups of forms assigned to Bradleya, sensu
stricto, and Poseidonamicus is very considerable I
have deferred its study until later. Nonetheless I have
distinguished 14 species of Bradleya, of which 10 are
new, and 4 (all new) species of Poseidonamicus.
Of the 75 samples examined, which yielded specimens
of Agrenocythere, new genus, more than onethird
had only one specimen, although three had over
100 each. Approximately 1000 specimens in all were
examined. Their distribution both geographically
(Figure 3) and stratigraphically (Figure 12) is presented
in Table 3. These occurrences of Agrenocythere
represent successful attempts to find specimens
among some 500 samples of deep-water sediments examined.
Seven species were found of which four are
new.
I did not consider the limited number of adult
female left valves (males were even rarer) found for
any given species, of those accounted for above, to be
sufficient to warrant a critical population study.
Therefore, I turned to the study of changes in form
between what seemed to be morphological isolates. In
prior discussion of this study with others, some concern
was expressed that there was insufficient information
about variation within species to warrant division
among species. This could be true in those cases
where only a few specimens from a few samples were
found, if the described new species were distinguished
only by minor differences in morphology. I have tried
to avoid such problems and have named new forms
on a few specimens only where I felt it was necessary
to focus on evidence for morphologic transition. Yet
with the exceptions of the two new larger species of
Poseidonamicus (P. major and P. minor) and Agrenocythere
hazelae, which could conceivably be more
than single species, most of those described herein are
morphologically distinctive and are thought to be consistently
so within a suspected biogeographical province.
In the several samples where 50 or 100 or more
specimens were found, the variation in individual
morphology is negligible compared to the differences
used to define species. Those instances, where changes
do occur, are discussed in the pages that follow. It
must be concluded for this stage in the understanding
of deep-sea ostracodes that the consistency of morphological
form among samples of populations of approximately
the same geological age is as equally impressive
as are the gaps between them. It is expected
that this separation will decrease as more samples of
older Tertiary forms are found.
Acknowledgments
For samples and specimens, appreciation is expressed
to W. A. van den Bold of Louisiana State University
(Trinidad samples), D. B. Erickson and Goesta Wollin
of Lamont-Doherty Oceanographic Laboratory
(Vema core samples), H. M. Cadot of the University
of Kansas (Southern Ocean sample), Francis Parker
of Scripps Institution of Oceanography (cores from
the Pacific), H. L. Sanders (Atlantis II samples) and
W. A. Berggren of Woods Hole Oceanographic Institution
(DSDP 117, 117A samples), A. H. Cheetham
of the Smithsonian Institution (French samples), N.
de B. Hornibrook of the New Zealand Geological
Survey and W. M. Briggs of Victoria University, Wellington
(New Zealand samples), Piero Ascoli of
Milan, Italy (Italian Miocene and Eocene samples),
P. A. Sandberg, University of Illinois (Austrian Miocene
sample), J. E. Hazel, U.S. Geological Survey
(Atlantic, Eocene sample).
The samples of the International Indian Ocean
Expedition were collected by me in 1964 and those
from France, with help of Jean Moyes and Odette
Ducasse and others, in 1969. Jesse Merida of the
Smithsonian Institution collected the samples from
the Kerguelen-Gaussberg Ridge (Eltanin Cruise 47)
in 1971.
I have used the illustrations of V. Pokorny, E. Herrig,
and H. J. Oertli as bases for identification or
morphological drawings as indicated. I would especially
like to credit Alexander Liebau of Berlin with
whom I had some brief, but spirited, discussions of
the problem of conservatism in fossal patterns. I borrowed
liberally from his ideas and those of Professor
Pokorny, who spent much of 1967 at the Smithsonian,
and subsequently extended them into areas that they
may seek to challenge.
Thanks is expressed to J. E. Hazel, P. C. Sylvester-
Bradley, and J. P. Harding for their critical reviews of
the manuscript and to Ruth Lerner-Seggev for her
10 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
assistance in preparation of some of the material for
this study and many intervening discussions. Laurie
Jennings helped prepare most of the samples and also
helped with the illustrations. Donna Copeland aided
in construction of the tables and typing of the manuscript.
The drawings were constructed by myself with
some aid on the stippled drawings from Manuela Farfante
(Figure 26 by Larry Isham).
Sediment samples from the Albatross collection and
the A. R. Loeblich collection were available in the
National Museum of Natural History, Smithsonian
Institution. Samples from the Glomar Challenger
cores were supplied to me through the curator, W. R.
Riedel, of the Deep Sea Drilling Project.
Work on this project was funded through Smithsonian
Research Foundation Grant SRF-436020 and
National Science Foundation Grants GA-17325 and
GA-12472.
After this report had been submitted to the editors
for publication I received from Alexander Liebau a
printed copy of his dissertation (Liebau 1971) for the
Doktor der Naturwissenschaften of the Technischen
Universitat Berlin. In this thoughtful work Liebau
discusses in more detail the basis of his analytical procedure
for pattern analysis ("Koordinatensystems")
and gives examples of several more genera than were
published in his earlier brief description (Liebau
1969) of this study. Of special interest are his analyses
of several species of Limburgina Deroo, 1966, Oertliella
Pokorny, 1964, and Quadracythere Hornibrook,
1952, which bear upon remarks made in the present
report.
Conceptual Development of the Genus Bradleya
A more formal description of Bradleya will be included
in the section on Systematics; however, one
can hardly begin to discuss the proper division of a
taxon as important as this one without some understanding
of the evolution of the concepts behind its
many past usages, and the background of taxonomic
theory that influenced its development. A critical review
of this evolution is attempted here.
CONCEPTUAL BACKGROUND.—Until 1952, when
Hornibrook introduced Bradleya as a new genus and
new generic conept, the Trachyleberididae had no
general taxon specifically for the acceptance of the
strongly reticulate forms. There was no particular reason
that this group of ostracodes should be recognized
separately. There was no theory providing for an explanation
of the function or development of reticulation.
The concept of Cythereis, invented by Jones
(1849) a hundred years earlier (as a subgenus of
Cythere), was intended for the recognition and inclusion
of the very ornate fossil marine ostracodes (spinose
and/or reticulate). Later it was much used for
almost any post-Jurassic ostracode with a complex
carapace morphology. It had just begun to be conservatively
applied to the type-species (Triebel 1940)
in the 1950s (see Sylvester-Bradley 1948, and Pokorny
1963). Among Recent ostracodes (since Sars 1866),
the concept of Cythereis was largely applied to species
like Pterygocythereis jonesi (Baird 1850) partly on
the assumption that grossly ornate cytheracean ostracodes
also shared more complicate or more primitive
appendages as compared with the simpler (both in
carapace and appendages) Cythere-like forms. The
introduction of the subgenus Hemicythere by Sars
(1925) as morphologically half-way between Cythereis
and Cythere is relevant in this regard. However, as
Miiller (1894) pointed out, the differences among the
soft parts of this family, then called the Cytheridae
(now several families), are slight compared to those
found in other living ostracode genera.
What Miiller failed to appreciate (the number of
described fossil forms was much less than now) is that
adaptation and the evolution of this group has been
primarily within the carapace and not in the soft
parts. [It must be remembered that Brady (1865)
could not bring himself to accept Cythereis after his
first very limited usage. His would be an extreme and
unworkable taxonomic position, even forty or fifty
years ago. Yet surely even Brady must have become
concerned about the growing lists of species (totaling
approximately 175 in number, of the 580 described by
him and his close associates), all of which he ascribed
to the genus Cythere.]
Skogsberg's (1928) attempt at a classification of
Cythereis, to include a broad spectrum of types of
appendage morphology, unfortunately neglected the
carapace. With the advent and influence of more
modern paleontological studies, especially during the
1930s, it soon became apparent that this wealth of
morphologic diversity could not be contained in the
available zoological taxonomic concepts. If for no
other reason, many new genera were needed just to
accept the increased multitude of Cythere species.
NUMBER 12 11
T H E SEARCH FOR PROGRESSIVE CHARACTER DEVELOPMENT.—
As new species continued to be discovered,
the problem of Brady remained. Among the many
species for the few genera described, there was no
theory of carapace development. Differences in carapace
ornament were described, but very few phyletic
sequences were noted. It was hoped that with the
discovery that the ostracode hinge had developed in a
progressive evolutionary sequence (Sylvester-Bradly
1948, Triebel 1940), that a taxonomic character with
morphological conservatism somewhere between the
outer carapace and the appendages had been found.
A. W. Sweyer, in 1949, as translated in Pokorny
1957:14), thought that because the carapace hinge
was generally protected "against the influence of the
environment and immediately adjacent to the organism"
that it should furnish a significant morphologic
indication of generic relationships. He suggested that
every ostracode genus would have a distinctive, if not
unique, hinge structure (and this is still stated in
modern papers).
It wasn't until after Hornibrook's description of
Bradleya (1952) that a progressive hinge classification
(apart from the old one based on molluscan hinges)
was advanced by Sylvester-Bradley (1956). Its absolute
value was quickly questioned by Pokorny (1957).
Pokorny feared oversplitting by paleontologists and
urged a return to respect for die taxonomic value of
the soft part anatomy in the classical zoological sense,
that of Sars and Miiller. Meanwhile, discoveries regarding
the stability of muscle-scar patterns were
being made (some by Pokorny) and many new species
were being described—but this begins to anticipate
the consequences of Hornibrook's work which was
just beginning to be received and considered.
There have been few places in the fossil record
where ostracodes characteristic of the deep sea were
found. Therefore, an important part of the evolution
of this animal group was unavailable for consideration,
while general morphologic and taxonomic concepts
about shallow water ostracodes continued to
form. Brady's (1880) Challenger report, while interesting
as a catalog of forms to be studied, is not in
itself a very useful instrument for the study of ostracode
morphology. It was with Hornibrook's work that
the first modern examination of some of the deeper
water forms (especially the reticulate species) began.
While Hornibrook, himself, did not have deep-sea species,
he began to recognize similarities between the
fossil and living ostracode faunas of New Zealand and
those described by Brady in 1880.
T H E CONCEPT OF BRADLEYA.—Confronted by the
absence of suitable taxa to receive his reticulate species
with amphidont hinges (Hornibrook still recognized
Cythereis as a Tertiary and modern spinose
genus, along with Brady's (1898) resurrected genus
Trachyleberis), he constituted the two new genera
Bradleya and Quadracythere. Both of these generic
concepts included reticulation (differences in pattern
not considered, only the presence of a reticulum),
prominent ventral and dorsal carina, two anterior
muscle (frontal) scars, and rectangular to subquadrate
lateral outlines.
A notice of major difference seemed to be placed on
the conformation of the hinge, especially the posterior
tooth (no doubt influenced by the work of Sylvester-
Bradley 1948). Bradleya has a "sometimes distinctly
denticulate, often obscurely denticulate or lobed [terminal
posterior tooth]," whereas Quadracythere has
"a stout, smooth posterior tooth, obscurely lobed"
(Hornibrook 1952:38, 43). As Pokorny feared
(1957), and others have also subsequently learned,
the subtle differences in tooth crenulation, while important
to note, are not that consistent as diagnostic
features (among the more ornate cytherid genera).
Or if they are used as such, there is a likelihood that
relationships among species, with different mechanical
requirements for valve closure, may well be overlooked.
A specific example of this oversight may exist
in the genus Cythere itself, which has almost become
monotypic.
Hornibrook's concern for the importance of the
hinge and its relationship to Cythereis and Trachyleberis
is evident, although at the same time he calls
attention to the difference in the smooth posterior
hinge tooth of B. dictyon and the denticulate tooth of
the type-species, B. arata. Bradleya semivera was described
as having a smooth lobate posterior tooth,
which may be important in the development of
Agrenocythere radula, but has little to do with Bradleya
dictyon or B. arata.
OVEREMPHASIS OF THE HINGE AND RETICULATION.—
Consequently, within these several years of concentration
on the importance of the ostracode hinge,
many workers (including myself, Benson 1959) were
quick to find species of Bradleya on the basis of what
now seems rather doubtful criteria. The name Bradleya
began to appear frequently as part of the binomen
12 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
of subquadrate or subrectangular reticulate trachyleberid
species. Puri's concepts of Hermanites (1954,
1955) and Jugosocythereis (1957) were not well understood
although the former was also widely employed.
By the early 1960s many other new generic
concepts began to appear, and critical examination of
muscle-scar patterns increased.
MUSCLE SCARS.—Although Hornibrook included
Bradleya semivera (Plate 1: figure 5 as close as I
could get to a form like Hornibrook's 1952, pi. 8: fig.
103) in his new genus, he fails to discuss the fact that
it has a different muscle scare (V-shaped, as noted
later by both Ruggieri 1962 and Hazel 1967) than the
kind required by his generic diagnosis (two frontal
scars). Even so, he both questions the inclusion of the
form, and suggests that the significance of the muscle-
scar pattern, as a guide to the evolution of the
Trachyleberidinae, had not been sufficiently realized.
In the section on the Family Trachyleberididae, (in
Moore 1961), Sylvester-Bradley made no group distinctions
among the member genera (though generally
subfamilies were not recognized in this work). He
comments on the importance of the caudal process,
the subcentral tubercule, and the lack of division of
the adductor muscle scars. At this time there was no
special significance applied to the differences in frontal
scars ("antennal scars") in this family. Subsequently
I described Australicythere (Benson 1964),
which had both divided adductor scars and a subcentral
tubercule, and I have subsequently seen several
trachyleberid deep-sea species with the typical Vshaped
frontal scar and a divided adductor scar.
Transitions between conventional V-shaped and divided
frontal scars and adductors have been amply
noted by Moos (1965), Deroo (1966), and Bassiouni
(1969).
Hazel (1967) discusses at length the problems involved
in resolving the relationships among the musclescar
patterns, and these arguments need not be
repeated here. He touches briefly on the "Bradleya
problem," and with Hermanites, Jugosocythereis,
Quadracythere, and some other genera, considers
their carapace to be intermediate between those typical
of the families Trachyleberididae and Hemicytheridae.
It is notable that van Morkhoven (1963) has
considered the divided frontal scar (included by
Sylvester-Bradley, in Moore 1961, as diagnostic of the
trachyleberids) as typically hemicytherid. Also, as
stated before, Ruggieri (1962) expressed concern over
the difference in muscle scars included within Bradleya
in attempting to place Cythereis pliocenica,
which he had previously identified as Bradleya dictyon
pliocenica (Seguenza) (Ruggieri 1959), and recognized
its similarity (by implication) with Bradleya
semivera Hornibrook.
TRACING CHANGES IN SEVERAL CHARACTERS.—It
soon becomes evident that monothetic definitions
(those that have both "necessary and sufficient" criteria)
of this complex group will not suffice. Comparison
of Bradleya and Carinocythereis-Cistacythereis
species groups provide an interesting exercise of this
point. Bradleya and Carinocythereis-Cistacythereis
have muted muscle-scar nodes, both groups lack caudal
processes, both have species with marginal and
median carina (see Sissingh 1971 compared to illustrations
in this report), both have species that tend to
become "naked" (smooth with the loss of the reticulum),
and both have hemiamphidont to holamphidont
hinges. Yet the frontal scars and details of the
reticular patterns (from what I can observe of the
patterns shown in Uliczny 1969) are different.
Through careful tracing of the development of these
forms, it has been shown (Sissingh 1971) that Falunia
is ancestral to Cistacythereis and Carinacythereis, and
I believe that probably one of the forms described by
Deroo (1966) as Limburgina (without divided adductors)
is ancestral to Bradleya.
I believe that examination of the above evidence
and the history of the study of this ostracode group
shows how reliance on any one criteria can at best be
provisional in the quest for the actual phyletic lineage
in ostracodes.
SUMMARY.—From what may seem like increasing
confusion with continued consideration of Bradleya
comes the following observations of this history, added
to the results of my own experience.
First, the assumption of relationship, based on similarity
or differences of details in hinge structure
(stressed heavily in the beginning, by Hornibrook)
among ornate ostracodes with different shapes or
muscle-scar patterns, can be misleading. The conclusion
of Schweyer (in Pokorny 1957) that the hinge is
immune to external selective environmental and convergent
influences is not likely to be true.
The ornate cytheracean ostracodes, while having
striking conservatism in soft parts, have a variable
and complex external carapace morphology. This
morphology, as presented in the past, does not lend
NUMBER 12 13
itself to classifications relying on the importance of a
few characters. A polythetic analytical method (requiring
analyses of variations in patterns, including
those of hinge structure) is required for their understanding,
and this will likely require many attempts at
clustering (by inspection and numerical) similar species
to form higher taxa rather than placing too much
faith in one or two "important" characters to distinguish
groups among a complex array of species.
Complexes of characters, such as muscle-scar patterns,
have elements that are relatively simple and
their changing state can be recognized. Although the
arrangement of attachment of the adductor muscles
are concerned with exerting mechanical advantage to
the closure of the valves, they are still internal and may
receive the same protection enjoyed by the soft parts.
By the same token, the cells that are responsible for
the formation of the carapace may be less subjected to
change in relative position than is their activity toward
the formation of stronger or weaker architectural
shell elements. Tracing of their pattern, through
mapping of their consequent patterns of reticulation,
may result in simpler yet somewhat more conservative
patterns than do the observations of the coming and
going of keels, carinae, costae, ridges, etc.
Even more conservative may be the presence and
distribution over the carapace of certain normal
pores, whose canals transmit sensory responses from
functional setae or possibly contribute to the balance
of body metabolism. These pores are often associated
with external surface conuli that may even be observed
in reticulate ostracodes. It is possible to trace
the patterns of their distribution from reticulate,
smooth, and even to spinose or conulate forms. (For
other remarks on this subject the reader is referred to
van Morkhoven 1962, Hazel 1968, Plusquellec and
Sandberg 1969, and Hanai 1970.)
There has been no general theory of development
of the carapace to explain how its architectural modes
(e.g., ribbed, reticulate, carinate) have become
adapted to their habitats or how the carapace shape
or ornament shape (which often are convergent in
form) has served as a solution to existence. Without
such a workable theory we must continue to be victim
of every nuance of form, without a synthesis, in much
the same way that Brady was. Certainly in consideration
of the evolution of a genus we must allow for a
history of invasion of different habitats of quite different
substrate stability or temperatures. Also there may
be more than one solution to existence in a single
habitat.
To resolve the status of Bradleya is to accept the
primary nomenclatural importance of the type-species
Cythere arata and begin again, only this time with a
working theory of carapace form evolution. A new
generic concept of Bradleya must be developed. Bradleya
is a genus with considerable differences among
species in the emphasis of the reticulum, from smooth
to extremely robust. These differences are expressed as
grades in emphasis of certain muri in several very
important species in the deep sea, and those species
restricted to the shelf regions of the western and
southwestern Pacific.
Bradleya dictyon (Brady, 1880) is a distinctive psychrospheric
species, which can be traced over much of
the world ocean floor. How closely is it related to
Bradleya arata? I will furnish evidence of the fact
that it is closely related, by showing how the general
shape and reticular pattern fits into the scope of the
variation of form in the genus. The slight differences
in hinge are no more than to be expected in different
yet related species living in different habitats which
have different strength requirements for closure of the
carapace.
What is to be done with "Bradleya" semivera,
whose trachyleberine frontal scar has been the concern
of several authors? I will demonstrate that those
characteristics that define "B." semivera are similar to
those of Cythere radula, Cythereis pliocenica, and
Cythereis hazelae. These latter species together with
several new species constitute a new genus (which
may include B. semivera or is closely related to one
that does) with a closer relationship to trachyleberid
genera than to thaerocytherid genera, of which Bradleya
is a member.
Lastly, in the systematic section I will present evidence
that some of the forms identified in the past as
Bradleya dictyon are species in their own right and
one represents another new genus, which I have
called Poseidonamicus. I will attempt to deal with
some of the other misidentifications of Bradleya and
to describe the ten new species that are in my collections.
Morphologic Trends in Bradleya
and Poseidonamicus
There are too many missing pieces of the puzzle to
14 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
8
FIGURE 4. —Reticular silhouettes of various modern forms of Bradleya showing the consistency
in the pattern of the reticulum and tracing the bridge structure (stippled area) from the small,
coarsely reticulate species of B. andamanae, new species (Figure 4:1) through intermediate expressions
of B. normani (Figures 4:3, 4:5) to larger forms of Bradleya dictyon with relatively
thinner muri and with more fossae added. Specimens from the following station localities 1,
OSS-01-255G, Andaman Sea; 2, IIOE 380C, Mozambique Channel; 3, Anton Bruun 766G,
Peru-Chile trench slope; 4, ALB 2751, Caribbean Sea; 5, IIOE 374, Mozambique Channel;
6, ALB 3376, Gulf of Panama; 7, ALB 2817, Galapagos Island; 8, OSS 01-170L, Tasman Sea.
NUMBER 12 15
speculate on an evolutionary model for either of the
genera Bradleya or Poseidonamicus, new genus, at
this time, as I have later with Agrenocythere, new
genus. These former genera represent both very
widely distributed and very diverse groups. Eighteen
species belonging to these genera (eight more in
Agrenocythere) are discussed in this report (at least
three more forms might have been considered, but I
did not feel confident about their spatial or morphological
relationships. It is possible to note some morphological
trends suggested by the ones that are better
known and which contribute to a theory of development
for these groups of species.
First, although there are several exceptions, the species
that have large individuals seem to occur in
deeper waters and die smaller ones are found in shallower
waters. This grade in size from larger to smaller
with decreasing depth, and perhaps increasing mechanical
agitation of the bottom, is often accompanied
by an increase in shell robustness. An example of
such a series would include Bradleya dictyon as a
representative of the deep sea, B. normani, which
ranges much more often into shallower slope habitats,
and species such as B. mckenziei, new species, and
particularly B. andamanae, new species, which are
common to shallower shelf environments. One can
imagine B.? telisaensis, if truly a Bradleya, to represent
the ultimate in this sequence toward small strong
adaptations.
The details of morphological change in this morphotypic
series, which in the present discussion only
correlates with an ecologic gradient (presumably also
evidence of adaptive invasion), include the deletion
or addition of mural elements from the reticulum, a
change in the relative mass of the remaining muri,
and consequently a change in general architectural
FIGURE 5.—A series of reticular silhouettes of different forms
of Poseidonamicus, new genus, including examples from the
Recent of (A) Mozambique Channel (IIOE 366A), (B) the
southeastern Pacific (ALB 4693), (c) the Tasman Sea
(OSS-01-17OL), (D) the Pleistocene of the south Pacific
(DWBG 74); and (E) South Atlantic (RC-8-91). The stippled
portion refers to a homologous region in each form.
This region is designated as a convenient reference but has
no special morphological significance. The series shows a general
increase in massiveness of the muri and the tendency of
particular muri to be displaced. These particular species are
not formally described in this report. This diagram is to show
one direction of change among several possible in this group.
16 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
mode of the carapace. This process might be termed
"mural accommodation" as the ridges seem to "trade
off" responsibility in carrying the work load. A particularly
interesting species to examine in this regard,
and which represents an important link in the chain
or series, is Bradleya normani. Two morphological
variants of this species are shown on Plate 7: figure 8
and Plate 8: figure 6. Both forms are found in depths
less than 500 meters. They come from very separate
regions (Galapagos Islands and Straits of Magellan)
where temperatures and exposure to water motion are
quite different. It is not known why one form is more
or less robust than the other. However, there is a
difference in robustness and this fact alone suggests
that adaptive change is occurring within this species.
Notice how the fine muri of one form are absent in
the other. In the second form the principal muri are
much heavier than in the first. It is through such a
shift that it is thought (Benson 1970) that the stress
load is being shifted from one architectural solution in
design to another.
Of course, it would be desirable to see this change
in mural accommodation occurring along a single gradient
in depth and bottom stability, but unfortunately
such examples are hard to find with a morphologic
series present. I have attempted a composite of grading
forms of Bradleya taken from many parts of the world
ocean and shown their reticular patterns in Figure 4.
This series is composed primarily of B. dictyon (the
deepest), B. normani (intermediate deptiis), and B.
andamanae, new species (the shallowest). One can
also see the changes in architecture much better in
comparisons between species. The shift of emphasis
from the major tricarinate design to a more parsimonious
celate design (with fewer structural elements) is
noticeable within the Bradleya {Quasibradleya) complex,
a new subgenus (including four new species, B.
dictyonites, B. Pro dictyonites, B. pliocarinata, and B.
paradictyonites). Although somewhat different in
final result, the loss or gain of reticular structural
elements that takes place between the almost totally
smooth Bradleya species and coarsely reticulate forms
constitutes a major replacement in architectural design.
A similar change in Poseidonamicus, new genus,
from delicate to robust, as a consequence of mural
displacement and enlargement (accommodation) is
shown in the reticular patterns and silhouettes in Figure
5, and in the species of Plate 10. The progression
shown in the patterns generally represents adaptation
to shallower or perhaps warmer waters. Notice the
parallelism in development, tiiat is mural accommodation,
of the two new smooth species, one in Poseidonamicus
and the other in Bradleya {B. nuda and P.
nudus) in Plates 7 and 11.
The loss of eye tubercules with invasion of deeper
waters is another morphologic trend. Eye tubercules
are present in robust species, but seldom in the less
coarsely reticulate forms.
It should be noted that celation (Sylvester-Bradley
and Benson 1971), or the process of addition of a
second, distally removed, outer layer to the shell, is an
important development observed in many genera.
Bradleya arata seems to be an extreme example of
this process. The addition of a second floor, architecturally
speaking, forms a sandwich shell structure in
which the strength of the shell wall is carried through
two lateral surfaces ("skins"), with increasing distance
from the neutral axis of the carapace design. It
is a lightweight solution to the problem of transference
of strength. In an ostracode, whose decreasing
rate of metabolism limits the amount of skeletal material
being secreted in deeper or colder water (as with
the change of number or position of major mural
struts), this design also represents an efficient use of
material. The concept of parsimony in design is very
important here.
Lastly, notice the occurrence of the structure on the
anterior lateral surface of Bradleya (referred to as the
anterior reticular field), which I have called the
bridge (Figure 9). This structure, common not only
to Bradleya but particularly emphasized in Jugosocythereis,
is composed of two parallel, elevated, sometimes
ponticulate muri, with cross-member elements
forming a truss that extends forward of the musclescar
node. I believe that it acts as a major transferer
of stress through resistance to compression (note that
its elements are often columnar in cross-section) to
distribute strength forward over an ever broadening
surface or stress field. However, it is but one solution
to the problem of stress in the overall anterior design.
Another would be to simply add more mass to the
carapace wall or a third might be to form a celate
sandwich, or the outer shell just mentioned.
It is the consideration of these forms as structural
alternatives which I believe allows us to explain how
and why so many quite different shapes can occur in
one genus or the same forms repeated among several
NUMBER 12 17
genera. Such theoretical consideration and examples
of evidence set in a proper time frame will allow for
eventual evolutionary model construction.
Origins of Agrenocythere, Bradleya,
and Poseidonamicus
The discoveries by Moos (1965) and Deroo (1966) of
late Cretaceous and Paleogene species with frontal-scar
patterns intermediate between those typical of thaerocytherids
and trachyleberids, suggest that some genera
of both families could have originated from the same
stock in the Cretaceous. Similarities in reticular patterns
can be seen between such diverse species as those
frequently identified as "Hermanites", for example,
"H." haidingerii (Reuss), Limburgina Deroo, Trachyleberidea,
those of Agrenocythere, new genus, and
Oertliella aculeata (Bosquet) (as shown in Figures 6
and 7) and even the form called Cythereis zygopleura
expressa by Herrig (1969). The analysis of muscle-scar
development, especially the frontal scar, as well as
that of tracing similarities in the reticular pattern
between modern and Cretaceous forms suggests continuity
in botii of these sets of features over a very long
time (also see Liebau 1969 for comparisons of fossal
patterns).
Evidence for the earliest appearance of Agrenocythere
consists of specimens found in the Eocene of
Italy, Trinidad, and from outcrops in submarine canyons
along the Atlantic margin of the United States.
The first two were first noted by van den Bold (1946)
and Ascoli (1969) as "Cythereis" or "Bradleya" hazelae
(now called A. antiquata) and die last by myself
in this report. They are not typical of the deep sea in
that they are smaller and more robust, suggesting that
they may have come from upper bathyal in contrast
to abyssal habitats. I have not found Agrenocythere in
the fossil record of the deep sea floor in rocks older
than Oligocene (Rockall Plateau, DSDP XIII, 117;
FIGURE 6.—Reticular silhouettes of (A) Agrenocythere gosnoldia,
new species; (B) A. americana, new species; (c) A.
pliocenica (Seguenza,1880) female; and (D) Oertliella aculeata
(Bosquet, 1852). The fossae (and the pore conuli of D)
are coded according to Liebau's (1969) scheme, after which
the latter form was constructed. Specimens from Hazel
2621C, ALB 2383 and ARL 446. These silhouettes were selected
to show the consistency in pattern of the reticulum between
geographic and possibly phyletically distant, yet related
forms.
18 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
the problem of Oertliella aculeata (Bosquet) from the
Eocene of Europe and its intermediate relationship is
discussed later). Miocene specimens of Agrenocythere
are relatively common, as are younger species.
Agrenocythere seems to be most similar to Oertliella
which was first described by Pokorny (1964a) based
upon a species {Cythere reticulata Kafka) from the
upper Turonian of Czechoslovakia. (These similarities
are discussed in detail on page 60.) The genera are
sufficiently close to cause difficulty in assignment of
some species, whose castrum (Figure 8) or dorsal
ridge (bullar series) may be obscure or transitional.
An example is O. aculeata (Bosquet) (Figures 61 and
62) whose reticular pattern is analyzed and compared
with several of the Agrenocythere species using Liebau's
method (Figures 6 and 7).
I have found a Paleocene (Thanetian) specimen of
the new genus Poseidonamicus (an unnamed species
from the South Atlantic; DSDP III, 21 A) and one of
Bradleya from the Upper Cretaceous (an unnamed
species of the same area; DSDP III, 21; a single
specimen with possible doubt about its original stratigraphic
position). Neither of these specimens yields
information suggesting the origins of their genera beyond
what is known from younger and better preserved
specimens. Both genera, known from the Oligocene
of the South Atlantic and common to Miocene
deep-sea samples and shallower species of Bradleya,
are well represented from Eocene onwards in the Australian
and New Zealand region.
In his description of the Upper Cretaceous (Turonian)
form Oertliella, Pokorny (1964a) gives a
brief passing remark about its resemblance to Hermanites
Puri (not known by me to be older than
Eocene), even though he did not know that the two
had dissimilar frontal muscle scars (divided J-shaped
in Hermanites, and V-shaped in Oertliella). The typespecies
of Hermanites {Hermania reticulata Puri;
from the Miocene, Alum Bluff Stage, Chipola formation
of Florida) has been poorly understood and is
illustrated herein (Plate 1: figure 10) with a closely
related older and better preserved form also shown
(Plate 1: figures 11, 12). This predominantly Cenozoic
genus may in fact be congeneric with, or include,
the subgenus Hornibrookella Moos (1965) whose reticular
pattern is similar. Its relationship to Cletocythereis,
sensu stricto (see type-specimen of type-species
on Plate 1: figures 1-4), is close, and represents a
particularly interesting problem, which is discussed
on page 22.
The problem of discrimination between these taxa
results in part from the possible effects of shallow
water (as suggested by Moos 1965) on not only modification
of the muri, and consequently the number of
elements of the reticular pattern, but also the possible
division of elements within the muscle-scar pattern.
Both Moos (1965) and Deroo (1966) clearly show
fission of the frontal scar (as well as the uppermost
adductor scar) forming a single upper and a Ushaped
lower scar, leaving a residual V-shaped scar.
This change takes place in Limburgina in the Upper
Cretaceous (Maestrichtian) and is still evident in the
lower Oligocene. Nevertheless, the fact of the change
suggests that Cletocythereis (with a partially divided
V-shaped frontal scar) could have evolved from Oertliella
(V-shaped frontal scar) retaining the basic reticular
pattern to become particularly adapted to shelf
depth waters. Hermanites on the other hand may not
be in the direct line of descent of Cletocythereis. It
may instead represent a series of local shallow-water
species whose development through Hermanites
{Hornibrookella) macropora (Bosquet, 1852) may
have produced other thaerocytherid genera. These
would include Thaerocythere itself or a group of even
more costate and smoother species, which are sometimes
also identified as Hermanites.
The place of Bradleya in this speculation is not
clear (Figure 9). Some Maestrichtian species of Limburgina
(as illustrated by Deroo (1966), such as L.
ornata (Bosquet) ) have a posterodorsal loop (shown
better in Deroo 1966, pi. 23; fig. 719, than in Liebau
1969, pi. 2: fig. 1), an ocular ridge, and the general
reticular pattern of earlier species of Bradleya; however,
the subcentral tubercule of these earlier species
is massive. The reticulum forms a castrum. There is
no bridge (although Liebau 1969 has suggested one;
it is less clear in Deroo's illustration). The similarity
of some of Deroo's species (for example the Montian
FIGURE 7.— (A) Reticular silhouettes of Agrenocythere hazelae
(van den Bold, 1946) and (B) male and (c) female of A.
radula (Brady, 1880). The fossae (and the pore conuli of c)
are coded according to the scheme of Liebau (1969). Specimens
from samples ALB 2751, IIOE 409A, and IIOE 363,
respectively. These two species would appear to be the principals
in the two lines of descent of Agrenocythere, new
genus. Whereas their shapes and sizes differ considerably
(even dimorphically) the patterns of the reticulum remain
(except for minor differences) remarkably constant.
NUMBER 12 19
Aquarius arx of the castrum
Capricornus Taurus
Gemin i
Alpha
nus
Beta
Scorpio solar sieve pores
specula
'4l/a
'?
i.
C
<F
m
porus castri
FIGURE 8.—Morphology of Agrenocythere, new genus: (A) The left valve of the carapace
(arrow indicates anterior) showing reticulum (numbers indicating the order of ballial fossae
within the castrum (1-12) ; see discussion on carapace morphology, p. 58). The principal pore
conuli (indicated by zodiacal and Greek names), some of the solar sieve pores, and the dorsal
bullar series (a, b and c). (B) The arx of the castrum (with part of the ballial series) showing
the specula, the porus castri and the muscle-scar pattern (not arrowed), (c) A dorsal schematic
drawing of the hinge (anterior arrowed), (D) The muscle-scar pattern with the mandibular
(m), frontal (f), and adductor-scar group (a) indicated.
D
NUMBER 1 2 21
bridge
ventrolateral carina
FIGURE 9.—The general morphology of the reticulum of Bradleya, showing its major elements,
including the penecircumferential ocular ridge and ventrolateral carina, the bridge structure
joining the muscle-scar node with the anterior reticular field, and the posterodorsal loop composed
of the median ridge joined with the dorsal carina.
species L. mauritsi (Marliere)) to Jugosocythereis
(common from the upper Eocene and Oligocene onward)
is also apparent. The bridge as well as the
eared posterodorsal loop is suggested in its reticulum.
Certainly very little modification of any of those Limburgina-\
ike forms or their immediate predecessors
could have produced Bradleya in deeper waters, or
for that matter as Hermanites in shallower waters. It
is too early to trace this lineage with the specimens I
have at hand. Liebau (1969) has proposed to do so,
and his results should prove valuable.
Poseidonamicus is a very special case of reticular
development. Its reticulum (Figure 10) has elements
vertically aligned in the posterior with a massive anterior
reticular field, no ocular ridge, and wide but
suppressed dorsal and ventrolateral carinae. In some
species the reticulum is formed with a somewhat circular
pattern of fossae around the region of the musclescar
node, suggesting the relic of a castrum. I
suspect that the ancestry of this genus reaches far
back into the Cretaceous, perhaps even farther than
that of Bradleya to its pre-Limburgina stock. Potential
ancestors of Poseidonamicus from continental strata
are unknown to me at this time.
In an even broader overview, I have suggested tfiat
Cythereis has a reticulum with elements and patterns
similar to those of Agrenocythere. One can carry these
comparisons to Trachyleberidea and Limburgina as
Liebau (1969) has done. It soon becomes obvious
that the solution to the problem of origins is to be
found in the understanding of Cretaceous ostracode
evolution. It may be demonstrated by identification of
22 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
ant. reticul
centra
muraf
ventrolateral carina
FIGURE 10.—The general morphology of the reticulum of Poseidonamicus, new genus, showing
its major elements, including the massive punctate anterior (ant.) reticular field, and the vertical
alignment of the muri and fossae of the central mural loop and the posterior reticular field between
the dorsal and ventrolateral carina.
conservative reticular elements in carapace morphology
among the many semireticulate species of this
time interval. In summary there seems to be a convergence
in both reticular patterns and muscle-scar
patterns of Bradleya and Agrenocythere toward the
reticulate ostracode complex of Late Cretaceous age
that includes the genera Limburgina, Oertliella, sensu
stricto, and Cythereis. One cannot help but wonder
if some of the family level distinctions, which show up
so clearly in Recent ostracode taxa, have validity or
relevance as the taxa merge in the Cretaceous. Could
not this stock group of forms represent a distinct
taxon of higher rank?
An interesting problem, which quickly tends to get
beyond the scope of the present paper, is the origin
and the phyletic relationship of Swain's (1963) genus
Cletocythereis. I have reillustrated one of Brady's several
specimens of Cythere rastromarginata (the designated
type-species; Plate 1: figures 1-4) from the
Challenger report that were obtained from the reefs
off Honolulu. I have included remarks about its description
in several places herein and designated a
lectoholotype (indicated by catalog number in the
plate explanation and identified by its photograph).
This genus is clearly not what Swain intended (Hazel
1967: 34), yet Cletocythereis is a genus in its own
right. Of considerable interest is the fact that Cythere
NUMBER 12
40-
23
3
U
u
O
c
<u
u
I
35-
30-
25.
20-
1 5 -
10 -
Agrenocythere
Bradleya *»
Poseidonamicus
15 20 25 30
Depth ( X 100, in meters )
FIGURE 11.—Observed depth distribution of all Recent species of Agrenocythere, new genus,
plotted as the likelihood of occurrence (relative percent) of samples found at a given depth
interval (500 meters) extending from sea level to 4500 meters depth (based on 31 Recent samples),
compared with the distributions of Bradleya (including only the species B. dictyon and B.
normani, based on 80 samples) and Poseidonamicus, new genus (based on 85 samples).
(now Cletocythereis) rastromarginata has a fossal
pattern very similar to that of Oertliella reticulata
(Kafka) ; its reticular pattern differs by the very massive
development of the dorsal and ventrolateral carinae
and the absence of any noticeable ornament
within the castral region. Especially important is the
partly severed V-shaped frontal muscle scar (Plate 1:
figure 4), which indicates the closeness of this genus
to the trachyleberid line of development. This relationship
is also suggested by its caudate posterior. (I
have also included illustrations—Plates 1 and 2, of
three other specimens of species not all named—of
the genus Cletocythereis from around the world, including
a topotype of Cythereis haidingerii Reuss to
illustrate how widespread this morphological form has
become.) Dr. Hazel has shown me Cletocythereis-\\kt
species from the Maestrichtian of Jamaica suggesting
that this genus, like the others discussed herein, is very
long ranging. It could possibly be antecedant to Hermanites.
As stated in the introduction, the study of Agrenocythere
has included a special problem of distribution
as well as the description of the evolution of its species.
These two subjects will be treated together in the
following section.
Distribution and Evolution of Agrenocythere
Recent species of the new genus Agrenocythere described
in this report have not been difficult to distinguish
from other reticulate ostracodes. The conformation
of the castrum seems particularly convenient for
the discrimination among different species. With the
exception of a few stations where both Agrenocythere
radula and A. spinosa, new species, occurred together,
no two species were ever found in the same sample.
Recognition of relatively consistent forms of A. pli24
SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
ocenica in Mediterranean Pliocene sediments has not
been difficult compared to the difficulties often encountered
in determining the variable ornate taxa of
shallower habitats in the same region. It was this
seeming distinctiveness and its apparent consistency
that first attracted my interest. A form whose environmental
distribution (for depth distribution compared
with deep-sea species of Bradleya and Poseidonamicus
see Figure 11) was well defined could provide a useful
indicator of past changes in depth of considerable
magnitude (Benson, n.d.c), or the flooding of tectonically
isolated basins by the psychrosphere (Benson
and Sylvester-Bradley 1971; Benson, n.d.b.).
Therefore, it was disquieting, if not surprising, that
this distinctiveness should become blurred in an attempt
to find the origins of Agrenocythere. The characters
that are used to distinguish among Neogene
species are less distinctive among Paleogene forms.
These same characters may be absent or confused in
possible Cretaceous ancestors. In Figure 12 I have attempted
to construct a possible model of the evolution
of Agrenocythere. The model becomes increasingly
problematic as the Mesozoic-Cenozoic boundary is approached.
I have found that there may be several
possible explanations depending on the weight of importance
ascribed to changes in particular parts of the
reticulum and on the increasing scarcity of evidence.
Only a few species of Agrenocythere are living
today. They seem to be confined to two very separate
geographic regions, the eastern Pacific and Caribbean-
Gulf of Mexico region (referred to sometimes as
the American Tropical Province), and the Indian
Ocean (my sampling is poor in the Pacific). With one
exception the species were neither indigenous nor
unique to any one physiographic basin. Agrenocythere
hazelae, extant since the Oligocene, now occupies
parts of both the Atlantic (Caribbean Sea) and the
Pacific oceans (near the Gulf of Panama) ; and the
two species, A. radula and A. spinosa, new species, are
found living concurrently in Mozambique Channel.
A. hazelae, which seems to have become extinct in the
Atlantic during the late Negogene (at least no Pleistocene
or Recent specimens have been found), had its
climax during the Miocene. It is found in Miocene
sediments in the Caribbean, the Mediterranean, and
the South Atlantic.
Through tracing of the several variations in the
morphology of the castrum, it seems likely that A.
spinosa, new species, evolved from A. hazelae as a
portion of this latter species invaded the Indian
Ocean around the southern tip of Africa (probably
during the late Miocene). The reticulum became
more spinose or tuberculate, the arx more confined,
and the reticulum less massive. Surprisingly, the part
of A. hazelae that invaded the Pacific, ostensibly
through a deep opening in the Panamanian or Columbian
region, did not alter significantly from its
parent form (except for an increase in size). I could
not find sufficient morphologic justification for recognition
of this Pacific variant as a separate species.
The relationship of Agrenocythere pliocenica to A.
hazelae is not an easy one to postulate. Because the
arx of A. pliocenica is divided on either side of the
pervial fossa and encompasses the fossa arcis and because
of the formation of a parapectus near the Leo
pore conulus, I judge it to be more closely allied to A.
hazelae and its derivatives than to A. radula. It is
distinguished by its produced posterior, lack of accentuated
dorsal bullae and general lack of definitive
pore conuli. The illustration of a Miocene representative
of A. hazelae by Ruggieri (1960, pi. 1: fig. 8)
from Ragusano, southeast Sicily, shows a much
greater similarity to the Atlantic form. (The specimens
I have from the lower Miocene of Ancona, Italy
—sent to me by Ascoli—are identifiable as Agreno-
FIGURE 12.—Stratigraphic distribution and evolution of
Agrenocythere, new genus, and related forms. Species (designated
by letters) are as follows: (A) Agrenocythere hazelae
(van den Bold, 1946) in the Pacific; (B) A. americana, new
species; (c, D, E) Caribbean, Atlantic and Mediterranean
geographic and temporal variants of A. hazelae (van den
Bold, 1946); (F) A. pliocenica (Seguenza, 1880); (G) A.
spinosa, new species; ( H ) A. radula (Brady, 1880) (i, K) A.
antiquata, new species; (j) A. gosnoldia, new species; ( L)
Oertliella ducassae, new species; (M) Oertliella aculeata
(Bosquet, 1852); (N) O. reticulata (Kafka, 1886); (o)
Cythereis ornatissima Reuss, 1846. More precise locality information
is given in Figure 3 and in Table 3 in the Appendix.
For quick reference locality regions (designated by numbers)
are as follows: 1, Malpelo Rize, eastern Pacific; 2,
North continental slope, Gulf of Mexico; 3, Trinidad; 4,
Cuba; 5, DSDP cores, South Atlantic; 6, Caribbean Sea; 7,
Singular occurrence of an extreme form of Agrenocythere hazelae
in the Miocene of the South Atlantic; 8, Submarine
canyon outcrops in the continental shelf of eastern North
America; 9, Rockall Plateau, North Atlantic; 10, Central
Mediterranean (including the Ragusano, Sicily section); 11,
Central and western Europe; 12, northern Italy; 13, Sicily
and central Europe; 14, Mozambique Channel; 15, Western
Indian Ocean and Indonesia. The dotted lines are suggested
lines of descent.
NUMBER 12 25
26 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
cythere, but their preservation is poor.) The castrum
of the Ragusano specimen is not clearly defined, but
the dorsal bullar series is pronounced (suppressed in
A. pliocenica), the posterior is acuminate and small
(enlarged in A. pliocenica), and the reticulum is coarse
(more like A. hazelae).
The Miocene Agrenocythere species in the Mediterranean
is a very important link in the sequence of
history of this region. As I have stated elsewhere
(Benson, n.d.b.), the Pliocene psychrospheric ostracode
fauna occurs directly above the evaporite series
of the Messinian in the sea floor of the Tyrrhenian
Basin. It is assumed therefore, that the Messinian represents
a critical time in the evolution of Mediterranean
psychrospheric faunas (which actually became
extinct with the onset of the Pleistocene). From the
present evidence, yet very incomplete, it would seem
that open access to the Atlantic from the central Mediterranean
existed during the early and middle Miocene.
Whether or not the Agrenocythere survived the
Messinian evaporite "crisis'' in the Mediterranean, or
reinvaded, remains a mystery. Because of the lack of
evidence of gradual change from A. hazelae (known
from Miocene sediments in the South Atlantic) to A.
pliocenica it could be postulated that this considerable
morphologic difference resulted from the severe adjustment
required of the species to survive the Messinian
crisis. This conclusion, however, is speculative
until the psychrospheric fauna immediately below the
evaporite sequence can be examined and described.
Unfortunately, as yet, no specimens of Agrenocythere
have been found in sediments of Miocene or Pliocene
age from the North Atlantic to confirm or compare
the nature of this contemporary fauna with that in
the Mediterranean.
After having discovered that Cletocythereis has a
nearly V-shaped frontal muscle scar, and realizing
that its fossal pattern and that of A. pliocenica were
very similar, I became aware of the possibility that A.
pliocenica might be an extreme variant of the same
lineage as Cletocythereis haidingerii or even from
some unknown link with Oertliella. Enlarged and reticular
ly accentuated forms of Costa edwardsii (Roemer,
1838) and Chrysocythere are known from the
Mediterranean Neogene, and A. pliocenica could
simply be a freak form with indigenous roots and
without a connection with an Atlantic ancestry. My
defense against these alternate hypotheses depends
upon homologies in two features, the castral arx and
the dorsal bullar series. A. pliocenica has a welldefined,
though centrally confined, arx with elements
homologous with those of A. hazelae, and weak but
definite indications of a dorsal bullar series. These
features are absent in the other possible ancestral
forms. Also these species have posterodorsal crests or
massive ventral and dorsal ridges, which do not appear
in A. pliocenica.
Although I examined many samples from the Pleistocene
and several from the Pliocene of the central
and northern Atlantic, I found no representatives of
Agrenocythere. I do not consider this negative evidence
conclusive, but implicit in this lack of discovery
is the possibility that Agrenocythere may have
become extinct in this region at the time of which the
rate of fall in temperature was greatest. It may have
survived only as species caught in confined and
warmed basins, or in more open circulatory ocean
systems with shallow rises or warmer currents such as
the South Atlantic, Indian, and Pacific ocean areas.
Agrenocythere survives in a very narrow temperature
range (approximately 4° to 8° C).
The predecessors of Agrenocythere hazelae (probably
going back to A. antiquata, new species) had less
well-developed castral elements. The arx was more
confined to the region of the specula and the pore
conuli were pronounced (but not developed into parapecti
along the circular rampart muri). A form intermediate
between A. antiquata and A. hazelae of
Oligocene age from Rockall Plateau (northeastern
Atlantic) is shown in Figure 57. A. gosnoldia, new
species, from the middle Eocene of the Atlantic slope
of North America is small and massive with wide
marginal rims and carinae. It is known only from one
area and is quite distinct from A. antiquata, which
ranges from the Caribbean and western Antilles region
to the Mediterranean.
The castrum of Agrenocythere radula, so far known
only from the Neogene of the Indian Ocean (including
southern Indonesia), has the primitive aspect
found in the ancestors of the A. hazelae group. I
believe that it is a more primitive form and probably
descended from the same ancestral stock as A. semivera
(Hornibrook 1952, pi. 8: fig. 103; also see Plate 1:
figure 5 of this report), the Paleogene, New Zealand
species. A. semivera lived in shallow water and retained
its eye tubercules. A. ? cadoti, new species, has
many traits in common with A. semivera and may
also be related.
NUMBER 1 2 27
In probing backwards toward the ancestors of
Agrenocythere the characters that are used to define
the younger species are lost or diminished. Those of
other genera become paramount. Those of Oertliella
or of the Cretaceous Cletocythereis-like forms or Limburgina
become dominant. The patterns of the reticulation
are retained, but the relationships are not clear.
One of the characteristics of the younger forms is that
they are all blind, presumably having invaded the
darker waters of the deep sea and lost the need of
sight. Their ancestors were not necessarily blind. They
must have come from shallower waters, or at least
had shallow water relatives which later evolved into
forms to be quite different than the large ornate psychrospheric
forms. Such "near antecedants" may be
"Oertliella" ducassae, which I have described for the
first time in this report (Figures 63-66), and O.
aculeata also illustrated herein (Figures 61, 62).
Systematics
The following hierarchic classification is used in
this report:
Subclass OSTRACODA Latrielle, 1806
Order PODOCOPIDA Pokorny, 1953
Suborder PODOCOPINA Sars, 1866
Superfamily CYTHERACEA Baird, 1850
Family THAEROCYTHERIDAE Hazel, 1967
Family THAEROCYTHERIDAE Hazel, 1967
In 1967, Hazel proposed the subfamily Thaerocytherinae
to receive his new genus Thaerocythere (using T.
crenulata (Sars, 1866) as a type-species) and the genera
Jugosocythereis, Hermanites, Verrucocythereis,
Quadracythere, Puriana, Aquitaniella, and Bradleya.
All of these genera contain species with strong hinges,
four single adductor muscle scars (dorsomedian scar
sometimes divided), and two discrete frontal scars.
The first antennae have five podomeres, and the exopodites
of the second antennae are well developed.
He expressed the conviction that Bradleya together
with the other genera, when dissections would be
made, would anatomically be hemicytherid. In 1968,
Hazel removed Verrucocythereis and questioned the
inclusion of Aquitaniella, but he added Swain's genus
Cletocythereis (which I would place elsewhere), and
Hornibrookella Moos, 1965. To these latter genera I
would also add Procythereis Skogsberg, 1928. I have
seen no specimens of Martinicythere Bassiouni, 1969,
and can make no judgment about its inclusion.
I have elevated Hazel's taxon to have status equivalent
to that of the families Trachyleberididae and
Hemicytheridae in the belief that (1) the soft-parts
are only in part similar to those of the Hemicytheridae
(there are almost as many trachyleberid characters
present as hemicytherid), and (2) because of a
considerable number of genera with quite long geologic
ranges, whose separate evolution is obscured
under the old classification. Some groups within the
thaerocytherids need to be recognized for their special
attributes. One of these is given subfamily rank below.
This elevation in rank of the thaerocytherines does
not do special violence to Hazel's phylogenetic model;
it only allows more room for recognition of relationships
for which he had relatively few forms for comparison
at the time it was suggested. Another consideration
must also be mentioned. The phyletic lines of
development are inseparable in the ancestral stock,
which is early Paleogene and Cretaceous in age. This
group could in fact be recognized as a fourth family,
depending on the practical recognition of a horizontal
versus a vertical classification. In either case the lines
of descent seem sufficiently discrete to now warrant
equal hierarchic rank.
Many of the generic characteristics present in the
morphology of the carapace sculpture of deep-water
ostracodes are adaptively modified in shallow-water
marine species. This often obscures their phyletic and
therefore their family or subfamily relationships. An
example is found in the celation that is characteristic
of the species Bradleya arata (Brady, 1880) the typespecies
of Bradleya. It is so strongly celate that the
basic pattern, shown in the more murate relatives, is
barely visible. Other examples in which carapace
morphology is strongly and convergently modified are
found in the two very important species (not thaerocytherid),
Hemicythere villosa (Sars, 1866) and
Cythere lutea (Miiller, 1776). These species are both
very heavily calcified, smoothed, and simplified. Their
shells are highly adapted (strengthened and streamlined)
to agitated sedimentary regimens and consequently
their taxonomic relationships to other forms
are obscured by the heavy calcification.
I see no reason to believe that fusion between the
fourth and fifth antennal segments or the development
of secondary reinforcement at the thoracic leg
knee could not also be adaptive, like that of carapace
28 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
architecture. The increased cross-section of appendages
of shallow-water marine species is characteristic
of many shallow-water inhabitants. Some degree of
caution should be exercised in the use of appendage
morphology for family level taxonomic characters, especially
when these strength modifications are involved.
I cannot help but suspect that the use of so many
of Sars' or Brady's species as types of new genera and
higher taxa is done out of an undeserved respect of
the importance of soft-part morphology, or in the case
of Brady, for the precedence of his work. In either
case, there is not a sufficient appreciation for the
significance of function and the selective pressures
responsible for the special forms inherent in shallowwater
ostracodes (not to mention the uncertain status
of the carapace morphology of many of these species).
Because the work of both Brady and Sars encompasses
more than one hundred thaerocytherid species, the
priority of the names they gave must be honored, but
as will be shown in some of the subsequent discussion,
the longevity of the name is not an indication of validity
of the species concepts they label. The problems
developed by the selections of Cythere arata Brady
and Cythere rastromarginata Brady as type-species
are cases in point.
I have added Procythereis Skogsberg to the Thaerocytheridae
on the basis that species of this genus, i.e.,
P. torquata Skogsberg and P. igandersoni Skogsberg,
both from Tierra del Fuego, have two frontal scars,
reticulate to punctate carapaces, amphidont hinges
with smooth to lobed posterior teeth, fused podomeres
(iv and v) in the first antennae, and with complicate
epipodites. I believe that the subquadrate shape of the
carapace may in part result from adaptation to shallow
high-energy habitats and that the patterns of
their reticulate sculpture are also significant. I have
studied topotype material of this genus and hope to
report more fully on the description of this important
Southern Ocean shallow-water genus at a later time.
Subfamily BRADLEYINAE, new subfamily
TYPE-GENUS.—Bradleya Hornibrook, 1952: 38.
DESCRIPTION.—Thaerocytherid ostracodes with amphidont
hinges, four single adductor muscle scars,
perhaps with the uppermost divided, with two frontal
scars, appendage intermediate between those of the
Hemicytheridae and the Trachyleberididae, with
strong ventrolateral and dorsal carinae, a strong characteristic
reticulum or its traces, and a blunt, noncaudate
posterior. Cretaceous to Recent.
REMARKS.—At present this subfamily is intended
to include the genera Bradleya, Jugosocythereis,
Quadracythere, Poseidonamicus, new genus, and Limburgina
Deroo, 1966, and the new subgenus Quasibradleya.
The relationship of this subfamily to the rest
of the taxa of the Family Thaerocytheridae, especially
Hermanites, Hornibrookella (with divided dorsal adductor
scars) and possibly Curfsina (Deroo 1966), is
not certain at this time. However, I am reasonably
confident that the five genera above share characteristics
in common and their relationships warrant recognition.
Of the questionable genera, Hermanites, sensu
stricto, and Hornibrookella may be synonymous. The
muscle scars of the types of Hermanites reticulata
(Puri) are obscured by bad preservation. The frontal
scar is divided with a U-shaped lower part, but I am
less certain about division in the upper adductor scar.
The reticular pattern is similar to that of Hornibrookella.
I have shown Cletocythereis haidingerii (Reuss)
to demonstrate their close similarity with the typespecies
C. rastromarginata (Brady). Cletocythereis
would not, in my opinion, belong to this subfamily.
I would add to the Bradleyinae a new yet undescribed
genus, which would include "Bradleya" oertlii Ducasse
(1964) from the Eocene of France.
Genus Bradleya Hornibrook, 1952
Bradleya Hornibrook, 1952:38.—Keij 1957:97.—Benson
1959:63.—Reyment, in Moore 1961 :Q336.—Morkoven
1963:158.—Ruggieri 1962:21.—Benson and Maddocks
1964:35.—Hartmann 1964:103.—Hazel and Paulson 1964:
1057.—van den Bold 1968:67.—Russo 1968:23[19].
TYPE-SPECIES.—Cythere arata Brady, 1880: 101, pi.
24; fig. 2a-c. Originally described from the Tasman
FIGURE 13.—Three important previously described species of
Bradleya: (A) Bradleya arata (Brady, 1880), from Recent
near North Cape, New Zealand, USNM 174336; x l l 5 ; (B)
Bradleya dictyon Brady, 1880), from off northern Chile, see
Plate 8: figures 7, 8 xlOO; (c) Bradleya normani (Brady,
1865), from off Peru, Eltanin station 48, lat. 14° 11', long.
77°08'; 4000 meters; xll5. These species exhibit special
cases of development within the reticulum. B. arata is so
grossly celate that only small openings or pores to the underlying
fossae remain (also seen are foveolae). B. dictyon, generally
the largest species, has thin delicate muri. B. normani
with bold nonexcavate, caperate muri, has secondary, as well
as primary, reticulation. (Compare also with Figure 14.)
NUMBER 12 29
30 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
Sea, lat. 39°32'S, long. 171°48'E, depth 150 fathoms
{Challenger Station 167). Lectoholotype designated
herein, specimen (British Museum, 'BM 154:9.4.1) is
not figured in the present report (see discussion on
page 33).
DIAGNOSIS.—Carapace subrectangular to subquadrate
with broadly rounded anterior margin and
squared posterior margin without noticeable caudal
process; dorsal and ventrolateral carinae. Surface
smooth to grossly reticulate with celate overgrowth
(in the type-species) ; the reticular pattern is grid like
rather than radiate and consistent within species, with
variation due to increased coarseness of some muri
and loss of others. Most species have traces of a bridge
or box-girder construction (Figure 9) within the pattern
of the anterior field of the reticulum, extending
from the region of the suppressed muscle-scar node
(absent in smooth forms) to the ocular ridge, which
extends from the position of the eye tubercule (absent
in blind species) to join with the ventrolateral ridge.
In some species a median ridge, postjacent to musclescar
node, is formed from emphasis of one set of
longitudinal muri and may be joined with the dorsal
carina at the posterior to form a posterodorsal loop.
This feature becomes well developed as the lower
element of the bridge decreases in size. Several species
having this feature are considered together as the new
subgenus Quasibradleya. Hinge hemi- to holamphidont
commonly with a lobed posterior tooth; vestibule
absent, duplicate broad. Muscle-scar pattern thaerocytherid
with two frontal scars. First antennae with
five segments (rv and v fused), epipodite with five
"fingers," knee apparatus in thorassic legs, exopodite
large in second antennae (Figures 15 and 16).
AGE.—Paleocene? Eocene to Recent. This genus
was very important in the Neogene, especially in the
deep sea. Although it is known to be common in the
Paleogene fossil record of New Zealand, it is less common
in Europe and very rare in the Paleogene of the
western hemisphere. It has been reported in the past
as ranging from Cretaceous to Recent (originally in
Hornibrook 1952), but evidence of this older record
has not been cited. "Bradleya" semivera Hornibrook,
found commonly in the Paleogene of New Zealand, is
not Bradleya. It is assigned herein to Agrenocythere,
new genus, in a different family. The Paleogene species
identified as B. dictyon by Hornibrook (1952) is
not that species, but is given a new name Bradleya
{Quasibradleya) dictyonites, new species, in the present
report. Depending on the significance of the evolution
of the median ridge, several species related to
this taxon are identified. This group is considered as
the oldest known. The Eocene species called Bradleya
kaiata by Hornibrook (1952) seems questionable and
is excluded. Among those Paleogene species identified
by Keij (1957) only B. kaasschieteri may belong to
Bradleya. Van den Bold (1957) stated that B. dictyon
had a worldwide range from Oligocene to Recent, but
I can validate a range of Upper Oligocene (Chattian)
to Recent in the deep-sea cores [DSDP III 22
(4, 2)] examined to date. A possible Paleocene Bradleya
species (or possibly transitional between Bradleya
and Limburgina) from New Zealand (sent to me by
W. Briggs; Plate 1: figure 9) is given herein.
REMARKS.—As stated in the earlier sections devoted
to discussion of the "Bradleya problem" and to
the evolution of the concept of Bradleya, I prefer to
restrict the concept to the type-species and those other
species with characters traceable to the type (the alternative
being to use the growing concept of Bradleya
arising from usage). This includes Bradleya dictyon
(restricted in the present work from Brady's
broad inclusion of several species under one, and excluding
Hornibrook misidentification, which actually
includes several new species). Added to these two
species are at least twelve more which include variations
of carapace architecture that are derived from
the more common and perhaps basic form of Bradleya.
The type-species Bradleya arata (Brady) is, as
Brady suggested, unusual in surface ornament (Figure
13). Few ostracodes have the overgrowth of celate
muri so extremely developed as does this form. What
appeared to van Morkhoven as sieve-pore canals are
actually the remains of the fossae that are otherwise
closed by celation. In this form the patterns of the
reticulum are masked, but the positions of the muri
are still evident (as suggested in the drawings of Hornibrook).
The reticular pattern becomes more obvious
FIGURE 14.— (A) Bradleya nuda, new species, from the upper
Pliocene of Japan; (B) Bradleya japonica, new species, from
the Recent of Japan; and (c) Bradleya andamanae, new species
from the Recent of northeast Indian Ocean (see Plate 7:
figures 5, 3, 4, respectively, for locality and specimen data).
These three enlarged photographs show homologous fine
structures such as pore conuli that are traceable through a
series of increasingly rugose ornamentation occurring in ever
smaller specimens (magnifications xl 10, xl30, xl60).
NUMBER 12 31
32 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
in other species of Bradleya (Figures 13 and 14), and
is very conspicuous in some of the small coarsely reticulate
forms (Figure 14c). In others it diminishes as
these species become truly without a reticulum except
for a few mural traces. This is shown in the development
of Japanese and Philippine Neogene new species,
B. nuda and B. paranuda (Figure 14A; Plate 7:
figures 5, 7) or possibly in Hornibrook's species Bradleya
pro arata (a questionable species from the evidence
I have examined). In one species {B. japonica, new
species) the reticulum is diminished in the anterior
marginal region, while remaining robust, but confused,
in the central lateral region (Figure 14B).
Other variations of the reticulation are found in
deep-sea forms, which become larger and more delicate.
Some of these illustrated in Plates 7 and 8 are to
be compared with the reticular patterns of Figure 4,
especially the extremely small but robust form of B.
andamanae, new species (Figure 14c).
Through examination of the variation of the reticulum,
a range of expression becomes evident. This
same range of from smooth to finely reticulate, to
robust, celate, masked, and massive, is found in the
carapaces of several other ostracode species groups
besides Bradleya. For the present the decision of when
or at what point a particular expression of reticular
robustness becomes of generic value, is likely to be
controlled by the accident of sampling or the absence
of intermediate material for examination.
Hartmann (1964) included a new species, B. reticulata,
in Bradleya. His specimens had soft parts, and
his study served as a basis for the first attempt at
diagnosis of this aspect of Bradleya morphology. Unfortunately,
this species is not Bradleya, nor even
thaerocytherid, but it is probably a shallow reticulate
echinocytherid. A six-segment first antennae as well as
his descriptions of the mandible are not applicable to
Bradleya. The actual soft-parts of Bradleya are more
severely modified and closer to those more typical of
the hemicytherid end of the appendage morphotypic
series found in cytheraceans. The appendages of
Bradleya dictyon are described below (Figure 15 and
16).
Van Morkhoven (1963) doubted whether "Cythere"
dictyon Brady, 1880, should be included in Bradleya
because it displays a prominent third (median)
lateral ridge and a more pronounced subcentral tubercule
than is found in Bradleya arata, new species. I
can only guess that he had the form of Hornibrook
(1952) erroneously identified as B. dictyon in mind
(Plate 1: figure 8 or Plate 8: figure 4), and not those
described or illustrated by Brady (1880) in the Challenger
study. Only one of the Brady forms (similar to
Figure 14c) could be construed as having a third
ridge and this was questioned even by Brady, although
perhaps for other reasons. The form chosen as
the type for B. dictyon (lectoholotype designated
herein; Plate 11: figure 18), from among the several
options of Brady's included variations in form, is demonstrably
part of the Bradleya carapace morphologic
series.
COMPARISONS.—Of the presently described thaerocytherid
genera of Oligocene and younger age, Bradleya,
as now constituted, is most closely allied to Jugosocythereis.
As the series of photographs of specimens
in Plate 8 reveal, there are similarities in general
shape and ridge configuration, as well as muscle-scar
patterns. As suggested elsewhere, species such as
"Bradleya" oertlii Ducasse and "B." kaasschierti Kiej
(Tertiary of western Europe) may constitute yet undescribed
genera closely related to Bradleya. Limburgina
of Late Cretaceous (Maestrichtian) age has species
similar to some of the older Bradleya {Quasibradleya)
species.
The relationship of Bradleya to Quadracythere is
still vague to me, although the two genera have shape
and muscle-scar characteristics in common. I have not
studied the reticular patterns sufficiently well at this
time to make a judgment.
Bradleya is related (but how closely is not sure) to
the new genus Poseidonamicus, described for the first
time in the present study. Both groups are subrectangular
with rounded terminal margins and have carinae
along the dorsal margins and the ventrolateral
regions. Both are thaerocytherid with amphidont
hinges. The principal ridges of the reticular patterns
differ. The anterior region of the reticulum of Poseidonamicus
is uniformly^ punctate (muri widened to
the exclusion of the rounded fossae) without the
bridge structure or the ocular ridge of either Bradleya
or Jugosocythereis, and the fossae and muri of the
posterior of Poseidonamicus are aligned vertically
whereas those of Bradleya are more randomly, if not
longitudinally, arranged. The muri of any given species
of Poseidonamicus usually are uniform in height,
although its species can range from very coarse to
absolutely smooth (with only the ghosts of the pattern
showing) as in Bradleya. This same kind of variation
NUMBER 12 33
in the strength of the reticulum, which is thus far
notable in several genera, both emphasizes the need to
trace its basic patterns as well as to form genera on
the basis of coarseness or smoothness with utmost
caution.
The new subgenus Quasibradleya consists of those
species of Bradleya that have tended to replace the
bridge structure of the reticulum with a stronger
upper mural element (at the sacrifice of the lower)
and have developed the median ridge of the posterior.
This gives these forms a tricarinate appearance.
SPECIES NOT BRADLEYA.—These species have been
incorrectly classified as Bradleya and should be assigned
to other genera (not a complete listing).
"Bradleya" saitoi Ishizaki, 1963; possibly Thaerocythere.
Cythereis aurita Skogsberg, 1928; a species of Radimella.
Cythereis pennata Le Roy, 1943; Jugosocythereis?, probably
a new genus.
Cythereis diegoensis Le Roy, 1943; Ambostracon.
Bradleya sp. cf. B. schencki (Le Roy), in Benson, 1959;
genus unknown.
Bradleya kaiata Hornibrook, 1952; genus unknown.
Bradleya reticlava Hornibrook, 1952; possibly Agrenocythere,
new genus.
Bradleya semivera Hornibrook, 1952; Agrenocythere.
Cythereis hazelae van den Bold, 1946; Agrenocythere.
Cythereis pliocenica Seguenza, 1880; Agrenocythere.
Cythere approximata Bosquet, 1852; Hermanites.
Cythere bosquetiana Jones and Sherborn, 1889; genus
unknown.
Cythere cornueliana Bosquet, 1852; genus unknown.
"Bradleya" oertlii Ducasse, 1964; I have examined this
unusual form and suggest that it, with "Bradleya"
kaasschierti Keij, may be a new genus, possibly related
to Bradleya.
"Bradleya" kaasschierti Keij, 1957; see above species.
"Bradleya" crassicarinata Hazel and Paulson, 1964; genus
unknown, with U-shaped frontal scar, possibly ancestral;
Taylor Group, Campanian, Texas.
Cythereis plummeri Israelski, 1929; genus uncertain.
Cythereis hazardi Israelski, 1929; genus uncertain.
Cythereis rugosissima Alexander, 1929; genus uncertain.
PROBABLE OR QUESTIONABLE SPECIES OF BRADLEYA.—
Because I have not seen specimens of the
following species or found their characters to be different
than originally described, these assignments
could not be confirmed. In the case of B. proarata
I have found only immature forms to be nude. What
the adult form is like is still to be determined.
Bradleya sendaiensis Ishizaki, 1966; Miocene of Japan.
B. semiarata Hornibrook, 1952; Miocene of New Zealand.
B. proarata Hornibrook, 1952; Paleogene of New Zealand.
SPECIES INCLUDED IN BRADLEYA.—The following
species are considered to be properly assigned to the
genus Bradleya. These include three previously described
species, of which one is the type and another
whose type-specimen may be in doubt {B. normani
(Brady)), and nine new species (one of which was
previously described, but misidentified).
Bradleya arata (Brady, 1880); New Zealand and surrounding
seas; Pliocene to Recent.
B. dictyon (Brady, 1880); deep-sea, cosmopolitan; Miocene
to Recent.
B. normani (Brady, 1865); deep-sea of the Atlantic, southern
and east Pacific Oceans; Neogene to Recent.
B. albatrossia, new species; China Sea; Recent.
B. japonic a, new species; western Pacific, Japan; Recent.
B. andamanae, new species; eastern Indian Ocean; Recent.
B. nuda, new species; Japan; Neogene.
B. paranuda, new species; Philippines, western Pacific;
Recent.
B. mckenziei, new species; Australian sector, Southern
Ocean; Recent.
B.? telisaensis (Le Roy, 1939); Indonesia; Miocene.
B. (Quasibradleya) prodictyonites, new species; New Zealand;
lower Oligocene.
B. (Q.) dictyonites, new species (for B. dictyon of Hornibrook);
New Zealand; Oligocene.
B' (Q-) paradictyonites, new species; Tasmania; Oligocene-
Miocene.
B- CQ-) plicocarinata, new species; South Australia; Miocene?
to Recent.
DIAGNOSES OF BRADLEYA SPECIES.—For the present
report, a brief summary of distinguishing characteristics
is given for each of the species included in Bradleya
with comparisons. The distributions and analysis
of variation within the species are left for a future
study.
Bradleya arata (Brady, 1880)
FIGURE 13A
Cythere arata Brady, 1880:101, pi. 24: fig. 2a-c.
Bradleya arata (Brady) .—Hornibrook 1952:39, pi. 6: figs.
80, 83, 86.
TYPE-SPECIMEN.—Brady failed to designate typespecimens,
therefore a lectoholotype has been chosen
and is hereby designated from among the few valves
studied by Brady and one reposited with the British
Museum. This specimen, BM 154:9.4.1, was originally
separated from the rest of Brady's specimens in 1954
but was never established as the lectoholotype. In my
opinion it is conspecific with recent specimens identified
by Hornibrook from North Cape, New Zealand.
34 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
A specimen from Hornibrook's locality is illustrated
here (Figure 13A) for comparison with a photograph
of a lectoparatype (BM80.38.52) shown in this report
as Plate 11: figures 16, 17.
TYPE-LOCALITY.—The species was described from
only one locality by Brady, Challenger Station 167, in
the Tasman Sea; lat. 39°32'S and long. 171°48'E,
depth 150 fathoms.
AGE.—Pliocene (fide Hornibrook 1952) to Recent
of Tasman Sea, New Zealand.
DIAGNOSIS.—Distinguished from other species of
Bradleya by its strongly celate reticulum in which the
muri have extended their uppermost or distal limits
laterally to join and seal the fossae (except for multiple
openings that resemble normal pores). The primary
pattern of the reticulum remains evident, however.
Traces of its extent are visible as smooth lines in
between densely scattered foveolae that cover the
outer tegmental layer; with eye tubercules and living
on the outer shelf.
COMPARISONS.—Bradleya arata is unique among
Bradleya species, in the extent of merger of its celate
muri. On superficial inspection it could be mistaken
for Bradleya nuda, new species, B. paranuda, new
species, or B. proarata, species with almost smooth
surfaces. B. arata has a short longitudinal ridge over
the region of the muscle-scar node. This ridge is all
that remains of the upper element of the bridge. Hornibrook
described B. proarata and B. semiarata from
the Paleogene of New Zealand which he considered
as closely allied to B. arata. These are described as
smooth with numerous pores. They both have eye
tubercules as does B. arata. The Eocene specimens of
B. proarata I have for examination are immature
instars and not well preserved. It is not possible to
determine whether they are celate or simply smooth
with solid carapace walls like B. nuda. I believe this
distinction is important and the apparent smoothness
of B. arata is convergent with that formed by the
disappearance of muri as shown in B. japonica, new
species, and in B. nuda.
Bradleya dictyon (Brady, 1880)
FIGURE 13B, PLATE 9.
Cythere dictyon Brady, 1880:99, pi. 24: fig. lh-i, 1, o, p, s,
t, ii [not a-g, j , k, m, n, q, r, v-y].—Brady and Norman
1889:152, 244.
?Cythere dictyon Brady.—Chapman 1906:109; 1910:433;
FIGURE 15.—A series of four instars of Bradleya dictyon
(Brady, 1880) showing changes in emphasis of some of the
muri in the reticulum with maturity: (A-C). The larger
three stages including the adult stage; (D) The smallest is
judged to be about the fourth stage before maturity. Comparison
shows the disappearance of a posteromedian ridge
and posterodorsal loop (B and c) the perpetuation of parts
of the bridge structure, and the appearance of the ocular
ridge (B) to join the anterior of the ventrolateral ridge.
Specimens from the eastern Pacific near Panama, Albatross
station ALB 3376; USNM 174378.
NUMBER 1 2 35
FIGURE 16.—Bradleya dictyon (Brady, 1880), dissection of a male: (A) the second antenna with
a long exopodite (ex); (B) the first antenna with fused segments v and vi; (c) the
copulatory apparatus, and (D) the maxilla. Same specimen as Figure 17, USNM 174382,
174383. From Eltanin station 63 off the Chilean coast, lat. 25°44'S and long. 70°58'W; depth
about 1900 meters.
36 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
1914:34, pi. 7: figs. 12, 13; 1915:41; 1919:25.—van
den Bold 1957:241.—Tressler 1954:435.—Egger 1901:
442, pi. 6: figs. 41, 42.—Guppy 1921:128.
Not Cythere dictyon Brady.—Chapman 1926:101, pi. 21:
fig. 7.
Not Trachyleberis dictyon (Brady).—Keij 1954:222, pi. 4:
fig. 9.
Cythereis species.—Tressler 1941:101, pi. 19: figs. 18, 19.
Not Cythereis dictyon (Brady).—van den Bold 1946 [fide]:
90, pi. 10: fig. 13.—Kingma 1948:80, pi. 9: fig. 8.
Not Cythereis dictyon (Brady) pliocenica (Seguenza).—
Ruggieri 1953:78, pi. 2: figs. 10, 11.
Not Bradleya dictyon (Brady).—Hornibrook 1952:39, pi.
6: figs. 81, 82, 84, 85.—van Morkhoven 1963:160.
Not Bradleya dictyon (Brady) pliocenica (Seguenza).—
Ruggieri 1959:176; 1960:4, pi. 1: fig. 5.
Not Cythereis (Pterygocythereis?) telisaensis Le Roy 1939:
275, pi. 11: figs. 9-16.
TYPE-SPECIMEN.—A lectoholotype; an adult, left
valve, is selected and designated herein. Brady (1880)
chose no type-specimen, nor have subsequent workers.
The specimen in the British Museum Challenger material
(BM 1961.12.4.32a) is illustrated in this report
in Plate 11: figure 18.
TYPE-LOCALITY.—North Atlantic in the vicinity of
Challenger Station 78 (lat. 37°24'N and long.
25°13'W, 1000 fathoms).
AGE.—Lower Miocene to Recent; southern hemisphere
and central Atlantic.
DIAGNOSIS.—Distinguished from other species of
Bradleya by its large size and delicate to only moderately
robust, generally foveolate reticulum. The dorsal
carina is poorly developed; two prominent muri extend
from the region of the obscurred muscle-scar
node toward the ocular ridge forming a bridge. Often
with large celate solar sieve pore canals. Blind and
confined to the psychrosphere.
COMPARISON.—Often in the past this species has
been confused with others. As presently conceived,
Bradleya dictyon is a very common and widespread
deep-sea ostracode species. I have had few occasions
on which recognition of Neogene specimens was a
problem. It is larger, more delicate and more elongate
than B. normani. The bridge is well formed but not of
great relief. The longitudinal ridges or upper and
lower elements of this girder-like structure are almost
always apparent. It is more reticulate than B. arata,
B. nuda, new species, or B. paranuda, new species,
whose solar pore canals are obscured. It lacks the
median ridge characteristic of B. andamanae, new
species, or the subgeneric Quasibradleya group of new
species B. pro dictyonites, B. paradictyonites, B. dictyonites,
or B. pliocarinata. It retains the mural elements
of the basic reticular pattern which is simplified
in B. mckenziei, new species, B. japonica, new species,
or B. normani.
DIMENSIONS.—The smaller lower Miocene specimen
(Plate 8: figure 7) is length 1.02 mm; height
0.65 mm; the larger Recent specimen (Plate 8: figure
8) is length 1.41 mm; height 0.86 mm.
REMARKS.—Brady in the original study (1880) of
Cythere dictyon confused at least three species of two
genera in his identifications. Because he did not designate
types for any of the Challenger ostracode species,
there is no way to know which of these several forms
he considered paramount in importance for the formation
of his original species concept. Later authors
were unsure of Brady's intentions, and because his
illustrations are wanting in detail and specimens such
as he described have been rarely found since, misunderstanding
of the taxon increased. Now with the
acquisition of abundant samples of deep-sea species, it
becomes necessary to begin again to sort out the different
forms of his very diverse group.
As indicated in the synonomy I have accepted very
few of the many identifications of Bradleya dictyon
made by others. A case might have been made for
selecting a type to conform to a majority usage of the
term dictyon if in fact such a usage had existed, but it
has not. The major advantage of the present decision
of strict usage is (1) it agrees with an important one
of Brady's several possible forms, (2) it includes most
of the misidentified forms in the same genus, and (3)
it represents a very widespread and abundant deepsea
ostracode population.
If Chapman (1906-1941) correctly identified
Bradleya dictyon in his many reported finds (for
which few illustrations were given), there is no evidence
of this fact short of restudying his collections. I
have not done this as I did not believe that this data,
considering the accuracy of its collection, would add
significantly to my own about the knowledge of the
distribution of this species.
Kingma (1948) stated that his specimens, together
with those of van den Bold (1946) from the Oligocene
of Cuba and Seran and those of Le Roy (1939)
from the Tertiary of central Sumatra (called Cythereis
{Ptergocythereis?) telisaensis), are all identical. If
so, then his is not Bradleya dictyon. Le Roy's species,
valid in its own right, is discussed and illustrated
elsewhere in this report.
NUMBER 12 37
FIGURE 17.— (A) The thoracic legs showing the knee apparatus (ka), and (B) the mandible
showing the five-"fingered" epipodite (ep) of Bradleya dictyon. Same specimen as in Figure 16.
38 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
The subject of Ruggieri's (1953, 1962) concern,
Seguenza's species Cythereis pliocenica, which he
thought could be Bradleya dictyon, is shown elsewhere
to be of a different species of a different genus
and family. Similarly, Hornibrook's (1952) form is
shown to be representative of a species complex (constituted
as a subgenus of Bradleya, i.e., Quasibradleya)
characterized by a strong median ridge (now
called B. {Q.) dictyonites, new species) having a distinctive
tricarinate aspect.
I am less certain of the correct identification of van
den Bold's (1957) forms, but I suspect that the coarse
reticulate species he has considered dictyon is normani
or a Caribbean antecedant.
Tressler (1941 pi. 19: figs. 18, 19, same specimen;
USNM 153811) was one of the few workers to actually
find B. dictyon; however he classified this
North Atlantic specimen in open nomenclature as
Cythereis species.
Many of the specimens illustrated by Brady (1880)
as Cythere dictyon are actually more closely allied, if
not identical, with his own species of C. viminea. This
is the same form that Ruggieri (1962) thought was
most similar to Cythereis pliocenica Seguenza (at the
same time recognizing species differences). I have included
this group of Brady's specimens in a new genus
Poseidonamicus under two new species {C. viminea is
considered nomen dubium). I have referred Seguenza's
species to a third new genus, Agrenocythere.
It is of interest to note that confusion about the
identification of Bradleya dictyon in large part stems
from a misconception of morphologic change that
takes place during maturation. Brady assumed that
the dictyon carapace becomes more coarsely reticulate
with age, toward senility, as he called it. I have examined
the allometric changes taking place in a series of
instars of the true Bradleya dictyon. As can be seen in
Figure 15 the reticulation continues to develop toward
the margins with increasing maturity, but the
robustness remains much the same. It should also be
noted that the posterodorsal loop is present in the
earliest instars. This feature is characteristic of some
mature thaerocytherids, especially Jugosocythereis.
The relationship between Bradleya dictyon and
Bradleya arata has been mentioned in several contexts
earlier. I would reassert that the reticular patterns are
very similar (as shown in Figure 13A, B) and that the
major features are of the same basic form although of
different parts of the morphologic range of the genus.
Older adult specimens (Miocene) are usually
smaller (about 1.0 mm long) than Recent specimens
(about 1.4 mm long).
APPENDAGES.—The appendages of a male specimen
of Bradleya dictyon are illustrated in Figures 16 and
17. It is noted that segments v and vi of the first
antennae are fused, the epipodite of the mandible has
five "fingers," the exopodite of the second antenna is
well developed, and the knee of the thoracic appendages
have slightly developed reinforcement. These
characteristics are typically thaerocytherid.
Bradleya normani (Brady, 1865)
FIGURE 13C, PLATE 1: FIGURE 7, PLATE 7: FIGURE 8.
CytKere normani Brady, 1865:379, pi. 61: fig. 5a-d; 1880:
101, pi. 17: fig. 3a-d [not pi. 26: fig. 4a, b].
Not Cythere normani Brady.—Chapman 1916:50, 73, pi.
6: fig. 2 [ = Australicythere polylyca (Miiller, 1908)].
TYPE-SPECIMEN.—In the original description of
Cythere normani, Brady (1865) mentions that several
specimens were examined; however, none is indicated
in such a way as to be considered the type.
The specimens later identified by him (Brady
1880) as C. normani, from the Challenger collection
(BM 1961 12.4.27), include some that are questionable.
Until a lectoholotype can be designated (I have
not seen his original material), the concept of the
species and the present identifications will have to be
considered on the strength of his illustrations (Brady
1865, pi. 61: fig 5a-d). Although somewhat crude
they incorporate many of the attributes of the species
as described here.
TYPE-LOCALITY.—Described originally from Abrolhos
Bank, which lies off Caravelas, Baia, Brazil between
17° and 18° south latitude. Brady (1880) later
identified specimens from between Heard and Kerguelen
Islands in the Southern Ocean in 150 fathoms
and also from off the west coast of South America
(1825 fathoms). Specimens illustrated in the present
report are from near Kerguelen Island (Plate 1:
figure 7) in the vicinity of Brady's collecting locality,
from the west coast of South America (Figure 13c)
and from the Straits of Magellan (Plate 7: figure 8).
AGE.—Stratigraphic range uncertain. Known from
Pliocene to Recent deep-sea sediments, but older specimens
identified by van den Bold (1957, 1968b) as
Bradleya dictyon could possibly be this species.
NUMBER 12 39
DIAGNOSIS.—Carapace large, but foreshortened,
with coarse heavy muri (primary reticulation) together
with various stages of their loss as the fossae
become fused. The elimination of mural elements
leads to a more simplified reticular pattern. The fossae
in the posterolateral region are usually large and
evenly spaced compared to those more crowded in the
anterior. The ocular ridge is weak. A median ridge is
absent in the posterior. In its place is a box-like arrangement
of a line of reticular cells similar to the
bridge structure of the anterior (whose pattern is apparent,
but whose mass is reduced). The dorsal carina
is not as strong as the ventrolateral carina. Marginal
teeth are concentrated along the ventral portions of
the anterior and the posterior. Deep-sea (primarily a
slope species) and blind.
COMPARISONS.—Bradleya normani is the most robust
of the deep-sea Bradleya species. Yet it is much less
murate than the smaller shallow-water species, such as
B. andamanae, new species, which is also differentiated
by a pronounced longitudinal ridge (believed
to be of a different origin than that of the Quasibradleya
species). Its reticulum is characterized by the
development of a few heavy muri at the expense of
other muri, which become fainter with decreasing size
(and depth of water). However, B. mckenziei, new
species, which has notably strong carinae (also an
ocular ridge), also has primary reticulation with secondary
divisions (secondary reticulation, like foveolation,
does occur but is not the same as the suppression
of muri mentioned here). B. normani is not easily
confused with B. dictyon (although Brady did possibly
mix the two species), as there seems to be little gradation
between the robust, abrupt subquadrate form of
the former and the elongate, more delicate form of
the latter. Undoubtedly, there will be samples where
these two merge, but they are not yet known. B.
normani bears a close resemblance also to B. japonica,
new species, which is coarser with very high and even
peaked muri with only a few traces of diminishing
(relic) muri.
DISTRIBUTION.—Eastern Pacific, Atlantic, Southern
Ocean; generally in upper bathyal depths.
DIMENSIONS.—Adults range in length, 0.95 to 1.25
mm; in height, 0.65 to 0.71 mm.
REMARKS.—This species has been seldom identified
since the two original studies of Brady (1865, 1880).
Chapman (1916, see synonomy) misidentified Australicythere
polylyca (Miiller, 1908) from elevated
marine muds from the Ross Sea and the Ross Sea
itself as Cythere normani. Van den Bold (1968b: 67)
suggests that "a fair amount of the specimens attributed
to Bradleya? dictyon in the Western Hemisphere
belong in reality to Bradleya? normani (Brady)."
This is probable as B. normani is known by me to be
distributed around the whole of South America, except
for the Caribbean, where my data are comparatively
sparse (especially in the fossil record). It is also
equally likely that indigenous species ultimately will
be described from this area, which will parallel the
development of a coarse reticulum in a way similar to
those of the western Pacific. I would speculate that B.
normani has a transitory and intermediate architectural
form that would not remain stable in a tectonically
active region.
It is noteworthy that in Brady's (1865) own remarks,
he compares Cythere normani with Cythere
arachnoidea (Bosquet, 1852), which is probably more
closely related to the new genus Agrenocythere. One
striking difference in the surface ornament between
the two forms is the presence of conjunctive spines
(probably pore conuli) on the coarse reticulum of C.
arachnoidea, which are totally absent on the carapace
of Bradleya normani.
Bradleya albatrossia, new species
PLATE 7: FIGURES 1, 2
ETYMOLOGY.—Named for the United States Fisheries
Steamer Albatross, which worked in the western
Pacific in 1900 and again in 1908.
TYPE-SPECIMEN.—The holotype (USNM 174318)
is an adult female (?) left valve, from the Recent of
the China Sea (Plate 7: figure 1). Paratype, USNM
174319.
TYPE-LOCALITY.—China Sea off Hong Kong in the
vicinity of Albatross station 5301, lat. 20°37'N and
long. 115°43'E, 208 fathoms depth.
AGE.—Recent of western Pacific; no specimens
with soft parts found.
DIAGNOSIS.—Distinguished from other known species
of Bradleya by its bold, high, yet nonexcavate
muri; the lack of a conspicuous discrete bridge structure
or median ridge complex; its sharp, angled reticulum
in the region of the dorsal carina, which fails
to form a continuous ridge; the presence of relic
mural struts crossing enlarged fossae; and the absence
of a prominent ocular ridge or an eye tubercule.
40 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
COMPARISONS.—The reticulum of Bradleya albatrossia
has been formed into a bold, box-work frame
similar to that of B. andamanae, new species, yet it
lacks any of the major structural members, such as
the median ridge complex or the dorsal carina, found
in other species of Bradleya. This species maintains a
strong reticulum by forming high mural webs at right
angles to the main carapace wall whereas other species
may accomplish the same function through the
formation of massive muri, celate muri, reduction in
relative size, forming major reticular members of increasing
the thickness of the carapace wall.
Bradleya albatrossia is very similar in many respects
to the larger form B. japonica, new species, in the
development of high muri, at least in the central and
posterior regions. B. japonica, however, is devoid of
reticular development in the anterior and posterior
regions, and both the dorsal and ventrolateral carinae
are much more evident.
Bradleya normani is generally larger but also differs
from B. albatrossia in the degree of reticular
development. These two species may represent parts
of a morphological series of which B. japonica and B.
nuda, new species, could also be components. More
discussion of these relationships is given elsewhere.
This species was found in two localities including
the type-locality and in the North Fiji Basin (Alexa-
Penguin Bank, lat. 11°5'S, long. 175°ICE; 2560 meters).
It is probable that this species is widely distributed
over the western Pacific at the present time.
DIMENSIONS.—Length of holotype 0.82 mm; height
0.57 mm.
DISTRIBUTION.—Western Pacific, from China Sea
to Fiji Basin, 200 to 2500 meters.
Bradleya japonica, new species
PLATE 7: FIGURE 3
TYPE-SPECIMEN.—The holotype (USNM 174320)
is an adult left valve, from the Recent of the Pacific
side of Japan (Plate 7: figure 3).
TYPE-LOCALITY.—This species is known only from
the Recent of Japan in the vicinity of Albatross station
3708, off Honshu Island (bearing S. 55° W.
distance 2.25 miles off Ose Zaki) in 60-70 fathoms.
AGE.—Recent; no specimens with soft parts found.
DIAGNOSIS.—Distinguished from other species of
Bradleya by the incomplete development of the reticulum
in the anterior and posterior regions near the
margin, the confused pattern of the reticulum in the
anterior, its broad ventrolateral carina, and its foreshortened
and peaked dorsal carina.
COMPARISONS.—This species is the only one known
which is nude or smooth in the terminal regions on
the carapace, and in the same adult stage has coarse
reticular elements over the rest of the carapace. This
difference in development in the reticulum is known
in early instars of Poseidonamicus, new genus (whose
fossae are filled in), but not observed to such an
extreme degree before in Bradleya. The earlier instars
of Bradleya dictyon (Figure 15) have the reticulum
somewhat incompletely developed near the anterior
margin, suggesting that B. japonica, new species, may
be neotonous.
The pattern of the reticulum is irregular, especially
anterior to the muscle-scar region. The species appears
to be transitional in form between the boldly
reticular species Bradleya albatrossia, new species, and
the smooth B. nuda, new species. All three of these
species are common to the western Pacific. Attention
is called to a murus that extends downward and
slightly toward the anterior from the high peak of the
dorsal carina. This same murus, one of the more
prominent on the central carapace of B. japonica is
clearly identifiable on B. nuda. Both species also have
a posteriorly directed process on the posterior cardinal
angle, as also does B. paranuda, new species.
DIMENSIONS.—Length of holotype 1.07 mm; height
0.58 mm.
DISTRIBUTION.—So far found only at type-locality
off Japan.
Bradleya andamanae, new species
FIGURE 14c, PLATE 7: FIGURE 4
ETYMOLOGY.—Named for the Andaman Sea,
around whose waters this species was found.
TYPE-SPECIMEN.—The holotype (USNM 174322)
is the left valve of an adult, from the Andaman Sea
in the northeastern Indian Ocean; Figure 14c.
TYPE-LOCALITY.—The Andaman Sea in the vicinity
of Oceanographer station OSS-01,260G (lat.
06°39.4'N, long. 98°52.0'E; 78 meters). Also found
commonly in the Bay of Bengal.
AGE.—Recent; no specimens with soft parts found.
DIAGNOSIS.—Carapace small in size with very
coarse reticulation. Distinguished from other species
of Bradleya by its reduced size and deep fossae; howNUMBER
1 2 41
ever, the pattern of the major reticular elements includes
a median ridge extending end to end with only
a partial ventral element of the bridge present. An eye
tubercule is present.
COMPARISONS.—This species represents an end
member in a morphological series that includes a
form with a reduced size, reduced number of mural
elements of the reticulum, and yet maintains a structure
of considerable strength potential. Similar to the
much larger form Bradleya albatrossia, new species
(1.1 mm compared to 0.7 mm length) in coarseness,
it has more recognizable principal reticular structures
such as the dorsal carina (even though irregular) and
the median ridge. It is also similar to the much larger
(1.1 mm length) B. {Q.) dictyonites, new species, but
it can be easily distinguished from this species just on
the basis of relative proportions of the reticulum to
overall size. It also bears some resemblance to B.
mckenziei, new species, in the anterior region, but the
muri become excavate and the fossae angular in this
latter species whose dorsal carina and margin is
straight and even. The average length of this species
is about 40 percent of that of the modern deep-sea
species B. dictyon.
The origin of this species is uncertain. It has a
median ridge as does the several species of Quasibradleya.
The general pattern of the reticulum and its
high webbed muri, however, suggest that the median
ridge may be the product of simple alignment of the
muri in a longitudinal direction, and the median
ridge is only analogous to that of B. {Q.) dictyonites.
With the reduction of mural struts or reticular elements,
it seems inescapable that convergence in pattern
would result.
DIMENSIONS.—Length of holotype 0.68 mm; height
0.44 mm.
DISTRIBUTION.—Northeastern Indian Ocean, depth
range generally from 60-70 meters to 500 meters
(limits uncertain at present).
Bradleya nuda, new species
FIGURE 14A, PLATE 7: FIGURE 5
TYPE-SPECIMEN.—The holotype (USNM 174323)
is a left valve adult, from the Pliocene of Japan
(Plate 7: figure 5).
TYPE-LOCALITY.—Upper Pliocene section, near
Okuwa, Kaga Province, Japan (Ozawa locality
F25510).
Diagnosis.—Distinguished from other species of
Bradleya by its smooth, nonfoveolate carapace, devoid
of a reticulum except for faint traces in the posterocentral
region. A posteriorly directed process surmonts
the posterior cardinal angle, and a sharp ridge runs
from the posterior end of the bold and smooth ventrolateral
carina around to a major spine on the posteroventral
margin. No eye tubercule is visible.
COMPARISONS.—Most similar to Bradleya paranuda,
new species, a smooth, reticulum-free Recent species
from the Philippines, except for a more indrawn anterior
margin and different and more abundant traces
of the reticulum (compare Plate 7: figures 5 and 7)
in B. nuda. Also very close in appearance to B. proarata
Hornibrook, which is about the same size (from
the Paleogene of New Zealand). This older species,
however, is sighted (eye tubercules present). The two
forms are undoubtedly very similar, and the difference
of sight and also the cause of the smoothness of
the carapace are significant factors in suggesting their
taxonomic separation. It is not yet known (but inferred
by Hornibrook) if the smoothness of B. proarata
is caused by loss of muri of infilling of fossae by
celation (the only specimens of B. proarata I have
seen are immature instars and not celate). The resultant
appearance could be much the same. As mentioned
in the comparative statements of the description
of B. japonica, new species, these two species
have similar elements of the reticular pattern in common,
although there are far fewer in B. nuda. It is
noteworthy that the pores along the anterior portion
of the ventrolateral carina are in pairs rather than
singular, as in the case in the posterior portion. These
same paired pores can be found in B. japonica and
even in B. arata.
Bradleya arata is similar to B. nuda in outline and
in the tendency to become smooth. However, no signs
of celation can be observed in B. nuda. Either the
developmental process has continued to completely fill
in the reticulum of the ancestors of B. nuda, or, on
the other hand, the reticulum has simply been absorbed
into the development of a thicker shell as suggested
by the intermediate morphological series stage
represented by B. japonica. The existence of B. japonica
is very strong evidence to suggest that the
nudity of B. nuda is the result of mural loss, and not
the paving over of the outer surface by a secondary
tegmen as occurs in the process of celation. The tendency
toward the removal of the reticulum is success42
SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
fully compensated for by an increase in the mass or
the thickness (including celation) of the shell, as well
as by a flaring of the ventrolateral ridge to produce a
more triangular (and theoretically stronger) cross-section.
DIMENSIONS.—Length of holotype 1.12 mm;
height 0.62 mm.
DISTRIBUTION.—Known only from the type-locality
at present.
Bradleya paranuda, new species
PLATE 7: FIGURE 7
TYPE-SPECIMEN.—The holotype (USNM 174325)
is an adult left valve from the Recent of the Philippine
Islands (Plate 7: figure 7).
TYPE-LOCALITY.—The Gulf of Davao, in the Philippine
Islands in the vicinity of Albatross station
5250; lat. 7°05'07"N, long. 125°39'45"E; 23 fathoms
AGE.—Recent; no specimens with soft parts found.
DIAGNOSIS.—Like the smooth form Bradleya nuda,
new species, this species is almost devoid of any traces
of the reticulum. Except for B. nuda and possibly B.
proarata, it can be distinguished from all other species
of Bradleya by this characteristic. The anterior margin
is very well rounded and exceptionally produced.
Traces of the reticulum are confined to a murus joining
the posteriors of the dorsal and ventrolateral carinae.
No eye tubercule is visible and although the
species was found in shallow water (23 fathoms) ; it is
presumed to be blind.
COMPARISONS.—This species is like Bradleya nuda
except for its produced anterior margin (neither species
has a discrete rim) and different and fewer traces
of the reticulum. Reinforcing mural struts are visible
next to the ventrolateral carina. A single mural trace
connects the posterior of the ventrolateral ridge with
the dorsal carina. So far as can be determined the
pore systems of the two nude species are the same.
The species are smooth and are not foveolate or celate
as in B. arata, which also has a small horizontal ridge
in the region of the muscle-scar node. The ridge joining
the posteroventer with the posterior of the ventrolateral
ridge (described for B. nuda) is also present in
B. paranuda.
DIMENSIONS.—Length of holotype 0.98 mm; height
0.57 mm.
DISTRIBUTION.—Known at present only from the
type-locality.
Bradleya mckenziei, new species
PLATE 7: FIGURE 6
ETYMOLOGY.—Named for K. G. McKenzie who
kindly furnished the samples (February 1967) in
which this species was found.
TYPE-SPECIMEN.—The holotype (USNM 174324)
is an adult left valve from Recent sediments of Bass
Strait, between Australia and Tasmania.
TYPE-LOCALITY.—Bass Strait south of Australia between
Tasmania and Flinders Island in the vicinity of
McKenzie station M290; lat. 39°58.7'S, long.
147°02.9'E; depth uncertain, less than 100 fathoms.
DIAGNOSIS.—Distinguished from other species of
Bradleya by its overall box-like shape caused by the
unusually straight and even, dorsal and ventrolateral
carinae that are joined by fairly evenly spaced mural
elements (slightly celate muri) of the reticulum. The
fossae are angular and the muri excavate. The ocular
ridge is not well developed, although the eye tubercule
is well formed. No median ridge complex is present;
however, traces of the bridge can be seen in the
reticular pattern. The fossae are enlarged by resorbtion
or exculsion of some of the muri. A posterodorsal
spine is present at the margin.
COMPARISONS.—Somewhat similar to Bradleya
normani in lateral outline, but the carinae are much
more conspicuous. Many homologous aspects of the
reticular patterns are noticeable among B. mckenziei,
B. normani and B. andamanae, new species (compare
Plate 7: figures 4, 6, 8). Differs from B. albatrossia,
new species, in the lesser strength and regularity of
the muri, as well as the eveness of the carinae.
DIMENSIONS.—Length of holotype 0.96 mm; height
0.65 mm.
DISTRIBUTION.—On the southern continental shelf
of Australia.
Bradleya? telisaensis (Le Roy, 1939)
PLATE 2: FIGURE 9
Cythereis (Pterygocythereis?) telisaensis Le Roy, 1939:275,
pi. 11: figs. 9-16.
Cythereis dictyon (Brady) .—Kingma 1948: 80, pi. 9: fig. 8.
TYPE-SPECIMENS.—The, holotype described by Le
Roy is reposited in the Government Geological Museum
at Bandoeng, Java (P.S. 1096a), where it was
subsequently examined by Kingma (see synonymy)
who considered it synonymous with Brady's species
NUMBER 12 43
Cythere dictyon. Le Roy also reposited paratypes in
the U. S. National Museum and one of these (USNM
56147) is illustrated here (Plate 2: figure 9).
TYPE-LOCALITY.—Described originally from the
Telisa formation, Miocene in age, from the Rokan-
Tapanoeli area of Ce.ntral Sumatra (locality Ho-
1512; Tapoeng Kiri area near Aliantan).
AGE.—Miocene.
DESCRIPTION.—After Le Roy (1939: 275) "Carapace
rather strong and thick, subquadrate in side
view, roughly quadrangular in cross-section, highest
anteriorly, thickest posterior to the middle, left valve
slightly larger than the right, best shown near the
anterodorsal angle. Dorsal margin straight to slightly
curved, sometimes shown an upward curve near anterodorsal
angle. Ventral margin slightly convex
downward. Ventral margin rather broad and flat due
to presence of moderately extended lateral processes
at the ventrolateral edge of the two valves. In some
specimens a short heavy spine projects backward from
this edge. Anterior end broadly rounded, oblique,
slightly compressed around the marginal border,
somewhat denticulate near anteroventral angle. Posterior
end bluntly angled, somewhat truncate. Surface
coarsely and irregularly reticulate. Two rather
strongly developed longitudinal ridges are situated
along the median line and the other near the ventrolateral
edge. Connecting these are numerous ridges.
The areas between the ridges are very irregular in
shape and form. Hinge margins well developed and
are typical of the genus. Marginal radial pore canals
straight and numerous. Line of concrescence coincides
with the inner margin throughout. Muscle scar poorly
defined, appears to be represented by a single depressed
area approximately along the median line in
the anterior half. Dimensions of the holotype, length
0.70 mm; height 0.40 mm; thickness 0.40 mm."
DIMENSIONS.—Length of paratype (USNM
56147), 0.68 mm; height 0.41 mm.
DISTRIBUTION.—Miocene of Indonesia.
DISCUSSION.—From examination of paratypes
(Plate 2: figure 9) it is apparent that Le Roy's species
is not conspecific with Cythereis dictyon (Brady) as
Kingma (1948) stated. So far as I can determine, it
was correctly designated originally by Le Roy, and it
is hereby reinstated.
Its generic status is another problem. Le Roy
guessed that it might be a pterygocytherid, which is
incorrect, and assigned it to the genus Cythereis,
which is also improper as now defined. It appears to
me to be closely related to Bradleya (which is implied
by Kingma's identification), but I believe that this
may be extending the concept of Bradleya too far
without stronger phyletic evidence. Therefore I place
it in this genus with some doubt.
Bradleya? telisaenisis (Le Roy) has the following aspects
in common with other Bradleya species: It has a
rounded, noncaudate posterior, well-developed dorsal
and ventrolateral carina (however massive and
blunted), a median ridge complex with the suggestion
of a ventral bridge member similar to the subgenus
Quasibradleya species group. The ocular ridge is diminished
like several Bradleya species as is the high
anterodorsal marginal area.
It is unlike Bradleya in that the marginal rims are
blunted or even absent (a variation perhaps typical of
a very shallow water form). The reticulum is disorganized
with many "unexpected" muri present. It is
obvious that the existence of this form indicates there
is still much more to learn about this group and this
genus.
Subgenus Quasibradleya, new subgenus
TYPE-SPECIES.—Bradleya {Quasibradleya) dictyonites,
new species.
DIAGNOSIS.—A group of species of the genus Bradleya
characterized by the development of a median
ridge complex formed from the upper element of the
Bradleya bridge, which is emphasized at the sacrifice
of the lower one, and a longitudinal median ridge
postjacent to the muscle-scar node, sometimes joining
the dorsal carina in the posterior to form a loop. This
subgenus, which is comprised predominantly of shelfdwelling
species, is thought to be indigenous to the
Australia-New Zealand region.
COMPARISONS.—One can see indications of the
subgeneric characters expressed in the smaller Miocene
form of Bradleya {Bradleya) dictyon (Plate 8;
figure 7), or possibly in B. {B.) andamanae, new species.
I believe that this subgenus is part of a larger
continuum characteristic of the genus Bradleya and
can see no value in raising it to the rank of genus.
This would, in my opinion, obscure the concept of the
overall development of Bradleya of which we can only
see in detail the changes of form in a small part. For
this reason the enumeration of these species continues
44 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
from those of Bradleya, which have been unassigned
to other subgenera.
OTHER POSSIBLE SUBGENERA.—For the present I do
not consider that evidence warrants the erection of
other subgenera within Bradleya. In my opinion
adaptive change to increase the strength in the carapace
has been accomplished by several different paths.
Convergent solutions to increased strength (easily
classified as subgenera) could be misunderstood at
present. I see no reason to group the remaining species
at this time, before having the chance to explore
the developmental theory farther. To make further
subgeneric divisions without more phyletic evidence
would just obscure the actual relationships. A case in
point is the problem of the origin of smooth Bradleya
species. These could have formed independently by
celation and by fossal infilling or by simple removal of
muri. Until links can be found or relic structures
recognized in surface detail, the end results would
appear to be the same. Another possible subgenus
might include those species similar to B. normani,
which would have muri of strength and number intermediate
between Bradleya {B.) dictyon and B. {B.)
andamanae. Again, I believe that present evidence of
the correlation between depth changes and the reconstitution
of the reticular pattern is insufficient to rule
out the strong possibility that simplification and
strengthening of the pattern does not occur numerous
times in the fossil record.
Bradleya (Quasibradleya) dictyonites, new species
PLATE 8: FIGURE 4
Bradleya dictyon (Brady).—Hornibrook 1952 [part]: 39,
pi. 6: figs. 81, 82, 84.
TYPE-SPECIMEN.—The holotype (USNM 174328)
is an adult male(?) left valve from the upper Oligocene
of New Zealand (Plate 8; figure 4 ) .
TYPE-LOCALITY.—The holotype was chosen from
Hornibrook's sample locality F6487, the Old Rifle
Butts Section, at Oamaru S.D., New Zealand; upper
Oligocene (Awamoan). Sample supplied to me by Dr.
Hornibrook in 1960.
AGE.—Upper Oligocene.
DIAGNOSIS.—A coarsely reticulate species of Bradleya
with a conspicuous median ridge in the posterior,
which joins with the upper element of the anterior
bridge structure (the lower element is proportionally
diminished to become almost nonexistent in the anterior).
The upper structural member of the bridge is
securely connected to the ocular ridge and not joined
at the posterior end to median ridge. The median
ridge is separate from the dorsal carinae (joined in B.
{Q.) prodictyonites, new species). The overall aspect
of these ridges together with the well-developed dorsal
and ventrolateral carinae give the carapace a tricarinate
appearance more strongly produced in this species
than in any other known in Bradleya. The eye
tubercule is not strong but present. The flange forming
the posterior marginal rim is wide and produced
in the posterodorsal cardinal region. This species is
believed to be sighted and probably lived in the outer
shelf region.
COMPARISONS.—Bradleya {Quasibradleya) dictyonites
is the most tricarinate of all of the named
Bradleya species (or of the subgenus; another similar
and closely related unnamed Recent species is shown
on Plate 1: figure 8). It has sharp conspicuous ridges
dividing the carapace reticulum longitudinally into an
upper and lower section. This feature also is found in
&• (Q-) prodictyonites in which the median ridge
complex (including the upper member of the bridge)
is disjunct (joined in B. (Q.) plicocarinata, new species)
from the ocular ridge and joined posteriorly to
the dorsal carina to form a loop. The Tasmanian
species B. {Q.) paradictyonites, new species, of similar
mid-Cenozoic age is much coarser in appearance with
celate muri. It has a different reticular pattern resulting
from fusion of particular mural struts. B. dictyonites
is much more robust, and its tricarinate appearance
and eye tubercule easily distinguishes it from B.
dictyon with which it was identified earlier by Hornibrook
(1952).
DIMENSIONS.—Length of holotype 1.18 mm;
height 0.65 mm.
DISTRIBUTION.—New Zealand, Paleogene.
REMARKS.—This form, now designated as a species
(and the type-species of a new subgenus), was first
noticed by Hornibrook (1952) but misidentified as
Bradleya dictyon, presumably because of the vague
status of this species at that time. His illustration of a
left valve (Hornibrook 1952, pi. 6: fig. 81) is Recent
(off North Cape, Station 27) in age (see Plate 1:
figure 8 of this report), is almost identical to the
upper Oligocene specimen illustrated herein (Plate 8:
figure 4). This Recent form is different from the
NUMBER 12 45
older one, herein described as a new species, in the
boldness of its reticulation and a difference in the
pattern in the posterior field. Nevertheless the general
conservatism in form for a considerable portion of the
Cenozoic is exceptional for an ostracode with eye tubercules,
and living in a shallow (shelf 28 fathoms)
environment. The evolution of B. {Q.) dictyonites
from B. prodictyonites, to the Recent species (being
studied by W. M. Briggs, Jr., and tentatively named
Bradleya zealandica (now nomen nudum), should
prove to be an interesting sequence. Hornibrook
placed some emphasis on the importance of the marginal
spines. So far I can find little of species-level
significance about these features as taxonomic characters,
although further work may suggest otherwise.
Hornibrook (1952, pi. 6: fig. 85) illustrates an
Eocene form, which he also identified as B. dictyon. I
do not know what species this is, but it is not B.
dictyon. The age range of B. {Q.) dictyonites as considered
here is only a small part (Oligocene) of that
suggested for B. dictyon by Hornibrook (Eocene to
Recent).
Bradleya (Quasibradleya) prodictyonites,
new species
PLATE 8: FIGURE 2
TYPE-SPECIMEN.—The holotype (USNM 174327)
is an adult female (?) left valve from the lower Oligocene
of New Zealand (Plate 8: figure 2).
TYPE-LOCALITY.—The specimens considered in the
description of B. {Q.) prodictyonites were from Hornibrook's
(1952) sample locality F5052 (Duntroonian;
lower Oligocene) from near Chatton S.D.,
New Zealand. Sample supplied to me by Dr. Hornibrook
in 1960.
AGE.—Lower Oligocene.
DIAGNOSIS.—A robust species of Bradleya distinguished
by its conspicuous ocular ridge (with eye tubercule),
prominent dorsal and ventrolateral carinae,
and particularly a median ridge in the posterior central
region that curves upward to join the posterior
end of the dorsal carina (also seen in B. {Q.) plicocarinata,
new species). The bridge structure reaches
forward from the muscle-scar node region toward the
broad ocular ridge, but does not join it, nor does it
join the median ridge to the posterior. The lower
segment of the bridge is short but strong with a knotlike
protuberance over the muscle-scar region (less
well developed in B. dictyonites, new species). The
posterodorsal carina area is truncate. The species is
sighted.
COMPARISONS.—B. {Q.) prodictyonites is most
closely related to B. {Q.) dictyonites, but is more
quadrate. The ocular ridge of B. prodictyonites is disjunct
from the bridge, and the posterior median is
joined much more conspicuously with the dorsal carina.
Other comparisons are mentioned above.
Plate 8: figure 2 illustrates the holotype of Bradleya
prodictyonites and Plate 8: figure 1, a Recent species
of Jugosocythereis from the western Indian Ocean.
Notice the similarity in the posterodorsal loop, the
ocular ridges, and the bridge structures of Jugosocythereis
with those of B. {Q.) prodictyonites. The caudal
process of Jugosocythereis is obviously more produced
and I am not convinced that one can trace homologous
fossae from one form to the other. Nonetheless
the general structures of the reticulum are quite similar
suggesting strong analogical convergence in general
architecture.
REMARKS.—I had only a few valves of this species
available for study. It could be an ecophenotypic variant
of B. {Q.) dictyonites, but evidence other than
the morphologic difference noted here will be required
to support this theory.
DIMENSIONS.—Length of holotype 1.08 mm;
height 0.64 mm.
DISTRIBUTION.—Paleogene of New Zealand.
Bradleya (Quasibradleya) paradictyonites,
new species
PLATE 8: FIGURE 3
TYPE-SPECIMEN.—The holotype (USNM 174328)
is an adult male (?) left valve from the Oligo-Miocene
of northern Tasmania (Plate 8: figure 3).
TYPE-LOCALITY.—The sample from which this species
is described was collected by N. G. Lane in about
1957 from the Fossil Bluff locality (Oligo-Miocene)
near Wynyard Beach on the north coast of Tasmania.
AGE.—The precise age is unknown, but the Fossil
Bluff locality has been described as Oligo-Miocene. A
more accurate determination is required, but the
means to do this were not at my disposal.
DIAGNOSIS.—The massive reticulum of this species
of Bradleya has strongly excavate muri and many of
46 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
the fossae have merged by removal of the mural struts
separating the principal members. The dorsal carina
is well formed as are the ventrolateral carina and the
median ridge complex. As in B. {Q.) dictyonites, new
species, this latter feature is joined to the ocular ridge.
It is disjunct over the muscle-scar node region and
continues over the posterior region to merge with the
rest of the reticulum at about half way from the node
to the posterior margin. The lower element of the
bridge is almost absent except for a knot-like configuration
over the muscle-scar node proper. The marginal
rim in the anterodorsal cardinal region is wide
and is strongly accentuated in the posterodorsal region.
The eye tubercule is large and conspicuous indicating
that this species, like the others of the B. {Q.)
dictyonites group, is a shelf dweller.
COMPARISONS.—Bradleya {Q.) paradictyonites is
most similar to B. {Q.) dictyonites, a larger contemporary
species, from which it can be distinguished by
its more celate, excavate, and simplified massive reticulum.
Also, the median ridge complex does not procede
as far toward the'posterior as that of B. dictyonites.
None of the other species of Bradleya seems to be
very close in morphology to this species, which, while
not well understood as yet, in large part justifies its
taxonomic notice here.
DIMENSIONS.—Length of holotype 0.86 mm;
height 0.59 mm.
DISTRIBUTION.—Known only from the type-locality
in Tasmania. It is considered an inner shelf inhabitant
judged on the basis of its massive morphology and
somewhat smaller size. Other ostracode faunal elements
in the sample tend to confirm this observation.
Bradleya (Quasibradleya) plicocarinata, new species
FIGURES 18, 19'
TYPE-SPECIMENS.—The holotype (USNM 174334)
is an adult male left valve from the Recent of the
Great Australian Bight (Figure 18).
TYPE-LOCALITY.—The Great Australian Bight in
the vicinity of Oceanographer station OSS-01,60K
(lat. 33°10.0'S and long. 130°54.5,E; 100 meters).
AGE.—Miocene (?) to Recent.
DIAGNOSIS.—This species of Bradleya {Quasibradleya)
is distinguished by its moderate size, elongate
shape, and unique formation of tricarinate ridges,
with the median ridge joined with the dorsal carina
forming a posterodorsal loop. The median ridge extends
anteriorly to join a complex of muri over the
muscle-scar region, which is characterized by the
prominent development of the central longitudinal
member (Figure 19). The dorsal element of the
bridge, which unites with the bold ocular ridge, passes
over this complex to join the median ridge. The lower
bridge element is prominent only in the posterior portion.
In general, the muri are foveolate, nonexcavate
and noncelate. The posterior cardinal angle is not
produced; however, the posterior margin is generallyenlarged
toward the posteroventer. Species is sighted
with an eye tubercule.
COMPARISONS.—This species is similar to Bradleya
{Quasibradleya) dictyonites, new species, in that the
median ridge has continuity and reaches forward to
join the ocular ridge. B. {Q.) dictyonites has no loop
formed by the ridge and its more flared dorsal carina,
and the reticulum covers the muscle-scar node in a
more knotlike fashion, rather than the prominent
ridges of B. {Q.) plicocarinata. B. {Q.) prodictyonites,
new species, has the posterodorsal loop, but its
posterior margin is foreshortened as the whole lateral
appearance is considerably more quadrate. The much
bolder appearance and lack of a loop separates B.
{Q.) paradictyonites, new species, from the present
species.
I have noted yet another species, or a variant of the
present species which is very similar to B. {Q.) plicocarinata
from the Miocene Mannum formation on the
River Marne about 50 miles west of Adelaide, Australia.
Some years back Mary Wade sent this material
to me, but I do not trust my locality data sufficiently
to describe this new form. It is characterized by a very
elongate shape in the male with a very flared extension
in the ventrolateral ridge causing the posterior to
seem bent downward. This flaring of the posteroventer
in the male is common to a number of species in
quite separate genera. Examples are "Cythere" dunelmensis
Brady, Cletocythereis rastromarginata (Brady),
and Agrenocythere pliocenica (Seguenza).
DIMENSIONS.—Length of holotype 0.88 mm; height
0.46 mm.
DISTRIBUTION.—Mid-shelf south of Australia. Miocene(?)
to Recent.
Genus Poseidonamicus, new genus
ETYMOLOGY.—Latin and Greek combination,
friend of Poseidon, god of the sea.
NUMBER 1 2 47
FIGURE 18.—Bradleya (Quasibradleya) plicocarinata, new species, stereomicrographs of the
exterior of the holotype, an adult male, left valve, USNM 174334, from the Recent of the Great
Australian Bight, Oceanographer station, OSS—01, 60K (x90).
48 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
Z&L ""V1-.' m :
FIGURE 19.—The region of the muscle-scar node in Bradleya (Quasibradleya) plicocarinata, new
species (same specimen as in Figure 18), showing the juncture of the partly formed bridge with
the median ridge and the muscle scars (x200).
TYPE-SPECIES.—Poseidonamicus major, new species.
DIAGNOSIS.—Distinguished from other reticulate,
holamphidont thaerocytherid genera, principally by its
suppressed but wide dorsal carina, the lack of an
ocular ridge, the regular, vertically aligned fossae and
muri (in reticulate species, or indicated in the pattern
of fine structure within the carapace wall of nude
forms) of the posteromedian portion of the reticulum,
the semipunctate to reticulate aspect of its anterior
region, and a characteristic, vertically oriented central
mural loop that occurs between these two regions in
the area of the muscle-scar pattern. Often there is a
conspicuous vertical ridge that joins the posterior of
the dorsal carina with the posterior of the ventrolateral
carina. Muri and solae are usually featureless
except for celate pores, both sieve and murate; few
spines other than marginal spines are present. Smooth
or nude forms with underlying reticular "ghosts."
AGE.—Cretaceous?, Paleocene to Recent of the
deep-sea.
OUTER CARAPACE MORPHOLOGY.—The carapace of
Poseidonamicus as viewed externally from the side
(Figures 10, 19) is bounded by moderately wellformed
rims and has a conspicuous ventrolateral ridge
and a less obvious or suppressed dorsal carina. These
latter features are usually joined at their posterior
ends by a third ridge, which is one of the emphasized
vertically oriented muri of the reticulum. The anterior
field of the reticulum, which can be defined as
that region in front of the muscle-scar node above the
large fossae of the ventrolateral ridge and anteroventral
of the well-formed angular fossae of the central
field, is composed of rounded almost puncta-size fossae.
No ocular ridge is present as in Bradleya and
there are no relief features such as the "levatum" as is
present in Abyssocythere (Benson, 1971). The fossae
of the anterior reticular field are almost never angularly
shaped as in Bradleya and are without secondary
conuli or spines giving this region a smooth and massive
aspect.
The posteromedian or "central" field of the reticulum,
which extends from the anterior field to the
three main ridges, is composed of open, well-formed
fossae with primary muri running vertically and with
smaller secondary mural struts crossing laterally.
These give the appearance of the net ladders formed
of the main shrouds in old sailing ships. This pattern
is very strongly emphasized in the more robust species
and becomes lost in the nude species. One segment of
this pattern, the one over the region of the muscle
NUMBER 1 2 49
scars (there is no pronounced node), is composed of a
centered or axial muri (over the adductor scars; the
"forum" region of Agrenocythere, new genus) that
extends secondary mural struts to join a vertical loop,
formed by the bordering muri of the anterior field
and the one in the central field (the one passing
through the position of conulus Leo; see p. 58).
The posterior field (from the vertical muri to the
posterior marginal rim) is less regular and undistinguished
as now understood.
At least one species {Poseidonamicus nudus, new
species), whose distribution is disjunct between two
geographically distant regions, is devoid of muri;
however, the pattern of the reticulum is still apparent
if the carapace is viewed in transmitted light (Plate
11: figures 1-11). Although the pattern of vertical
continuity of the principal muri of the central field is
not as well ordered as in coarsely reticulate forms, the
basic elements are nevertheless apparent.
The pore patterns of Poseidonamicus are not yet
well understood. There are, however, some pores that
seem homologous with those of other genera such as
Bradleya or even Agrenocythere. By close inspection
of Figure 20 it can be judged that pores (without the
conuli) Leo, Charon, Scorpio, Capricornus, Alpha,
Beta, Taurus, and Chi are present (see p. 58 for
terminology). The absence of conuli and the presence
of celate solar pores that may be absorbed into the
widening of muri may cause difficulty in identifying
some of these principal pores.
In many of the carapaces of the early instars, the
anterior field is completely filled in as though snow
were obscuring the basic reticulum topography. It was
noticed also that pore conuli were present in some
areas at this stage in development. This observation
suggests that morphological similarities among higher
taxa may exist in the instars and become obscured in
FIGURE 20.—Poseidonamicus major, new species, a micrograph of the exterior of the holotype, a
left valve, USNM 174335, from the Mozambique Channel, Indian Ocean, IIOE Station 368C
(xl50), showing the pattern of the reticulum and pore systems for comparison with those of
Bradleya and Agrenocythere, new genus.
50 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
the adults. The form is blind and without an eye
tubercule.
INTERIOR CARAPACE MORPHOLOGY.—The following
features are noted.
Hinge: Holamphidont with only slight indications
of location in the underside of the posterior tooth.
The anterior tooth of the right valve is often massive
and stepped. Otherwise the hinge is undistinguished.
Duplicature: Without a vestibule. The simple radialpore
canals with slight intermediate swelling number
between 14 and 16 in the anterior and a few less
in the posterior.
Muscle-scar Pattern: Consists of four undivided adductors
and two frontal scars.
APPENDAGE MORPHOLOGY.—This diagnosis of the
soft part anatomy of Poseidonamicus is based on the
dissection of a female specimen of an undescribed
form of Poseidonamicus (Figure 21) from Mozambique
Channel (IIOE 416A, dissection 124; USNM
174379-80). This specimen unquestionably is Poseidonamicus;
however it is not P. major. Live specimens
with soft parts are rare and this one was the
best available at this time.
The first antennae are divided into five segments
with podomeres v and vi (following scheme of Miiller
1894) fused. The second antennae are moderately
robust with a long well-formed exopodite. The mandible
has a "two-fingered" epipodite and only one
major brushlike setae was observed. The thoracic appendages
have poorly developed knee apparatus and a
very small proximal carrot-like bristle was seen.
The appendages seem typical of several outer-shelf
hemicytherid species that I have examined, yet the
carapace characteristics suggest that these aspects are
not by themselves reliable for taxonomic determination
on the family or generic levels. The antennae are
very similar to those of Bradleya as are the thoracic
legs and maxillae. The epipodite of the mandible is
simpler however, with only two "fingers" observed in
that of Poseidonamicus compared to five in Bradleya.
The significance of this difference is not fully understood,
but it was also noticed that the carrot-like setae
of the basal podomere of the legs and the mandible is
also smaller. In general the differences in appendage
anatomy that exist between the two genera are minor
as compared with those of Agrenocythere, new genus,
described on pages 60-62.
COMPARISONS WITH OTHER GENERA.—For the present
no other genus seems closely related to Poseidonamicus.
It is a deep inhabitant of the psychrosphere
and seems to have changed little since the early Cenozoic
(Paleocene). The older forms have been found
only in deep-sea cores (DSDP III) and then only a
few specimens. In the present report only the younger
species are described.
Poseidonamicus is believed to be related to Bradleya
on the basis of similarity in lateral outline in
which both forms are broadly rounded anteriorly and
have very blunt caudal extensions. The patterns of the
reticulum are also similar, although the formation of
prominent ridges from the muri between the dorsal
and ventrolateral carinae is different. The anterior of
Bradleya has a bridge structure, as does Jugosocythereis,
and a median ridge in the posterior area is often
present; whereas the anterior of Poseidonamicus is
devoid of ridges of any kind and seems to maintain
strength through a general increase of mass within the
reticular field. The pattern of the reticulum in the
posterior of Poseidonamicus is dominantly vertical,
whereas that of Bradleya is either horizontal, uniform,
or irregular. This genus is thought to have been confined
to the deep-sea during the Cenozoic. Comparisons
with older fossil forms known from shallow water
are not obvious to me at present.
INCLUDED SPECIES.—For the purposes of this report
I have not made a detailed study of all of the possible
species of Poseidonamicus that I believe may be represented
in the Recent and fossil record of the psychrosphere.
Five possible species are discussed here, of
which four are included as valid and diagnosed, and
the fifth is included, but its usability as an identifiable
taxon is questioned. The stratigraphic ranges cited
below are tentative. Those given as Recent probably
are much longer lived than now known.
Poseidonamicus major, new species, deep Indian, South Atlantic
and Southern Oceans; Oligocene?, Miocene to Recent;
designated as type-species.
P. minor, new species, eastern Pacific; Pleistocene to Recent.
P. nudus, new species, western Indian Ocean and southeastern
Pacific; Recent.
P. pintoi, new species, continental slope, western South Atlantic
Ocean; Recent.
P. viminea (Brady), 1880: 94, pi. 18: fig. 3a-c.
Brady, in the Challenger report, described a single
specimen now in the British Museum (BM 81.5.33;
holotype by virtue of monotypy) from station 146,
Southern Ocean between Prince Edward and Crozet
Islands (lat. 46°46,S and long. 45°31'E; 1375 fathoms)
as Cythere viminea. From this specimen, its
NUMBER 12 51
FIGURE 21.—The appendages of a female specimen Poseidonamicus species from Mozambique
Channel (locality IIOE 416, see Table 2; dissection 124, USNM 174379, 174380), the same
specimen (USNM 174381) whose carapace is shown in Plate 11: figure 13. (A) The second
antennae has a long exopodite (ex); (B) the first antennae has segments v and vi fused; (c,
E) the knees of the thoracic legs have some additional reinforcement; (D) maxilla; and ( F ) a
two-"fingered" epipodite (ep) in the mandible.
52 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
surface worn and now broken (see Plate 11: figure
15), he deduced the following reticulum description,
which he must have considered diagnostic. "Shell
sculptured with closely set polygonal fossae and produced
round the margins so as to form a stout encircling
flange" His illustration and the type-specimen
show this "flange" to be the anterior and posterior
marginal rim, which unfortunately is a feature common
to many ostracode species and genera. Further
evidence of Brady's lack of understanding of this
taxon is the fact that he identified and illustrated
(Brady 1880, pi. 24: fig. le-g) another specimen of
this form as Cythere dictyon which he suggested was
a male of C. dictyon. Apparently the artist failed to
see the features in common between these specimens,
as the vertical muri on the type-specimen of C. viminea
that are characteristic of Poseidonamicus are not
shown in his drawing. This species was only identified
once (Chapman 1910: 433) since Brady's original
description almost one hundred years ago. Because of
the condition of the type-specimen (the only specimen
considered by Brady in this species), the confusion
of identification of this taxon by Brady, and the
failure to define adequate criteria for its identification
(both in description and illustration), I suggest that
the species is not identifiable (except to generic assignment)
and therefore the trivial name viminea be
considered nomen dubium.
Although four of several possible species are first
described here, the purpose of this report is not to
analyze the whole morphological range of Poseidonamicus
(a very common, diverse and widely distributed
psychrospheric genus), but to show some of the
morphological trends that resemble those of Bradleya.
This relationship was confused by Brady in his original
description of Cythere dictyon (now Bradleya dictyon)
and his failure to consistently identify C. viminea.
Unlike Agrenocythere, new genus, which has also
been previously identified as Bradleya, and which I
have described in detail on pages 58-62, species that I
would class with Poseidonamicus have never been recorded
to my knowledge under any name during previous
studies of living or fossil deep-water marine
ostracodes. Considering its abundance in deep-sea
samples and the very wide distribution of this particular
ostracode, this lack of discovery is somewhat of a
mystery. Brief diagnoses of the new species follow.
Poseidonamicus major, new species
FIGURES 20, 22; PLATE 8: FIGURE 5; PLATE 10: FIGURES 1-6
FIGURE 22.—Drawings of the carapace Poseidonamicus
major, new species, from Mozambique Channel (IIOE
363B) showing (A) the general aspect of the surface sculpture,
(B) the fused duplicature and thaerocytherid musclescar
pattern, (c) the holamphidont hinge elements, and (D)
a dorsal view of a whole specimen. Scale = 100 microns.
NUMBER 12 53
HOLOTYPE.—Left valve, adult female from the Recent
of Mozambique Channel; Figure 20 (USNM
174335); paratypes (USNM 174354).
TYPE-LOCALITY.—Indian Ocean, Mozambique
Channel southwest of Europa Island in the vicinity of
IIOE station 368c; lat. 23°00'S and long. 38°37'E;
2995 meters depth; bottom temp. 1.6° C.
AGE.—Oligocene?, Miocene to Recent, on the basis
of present data. Live specimens found.
DIAGNOSIS.—A moderately reticulate species of the
genus Poseidonamicus (see pp. 46-52) with strong
principal muri in the central field and broad punta
in the anterior field. The shape in lateral view is
elongate subrectangular. Species is blind.
COMPARISON.—Among the various forms of Poseidonamicus
observed, P. major is somewhere near the
mean of the distribution of robustness within the possible
development of the reticulum. A nude form (Poseidonamicus
nudus, new species), one with only
traces of reticulation, is described here along with P
minor, new species, a very strongly reticulate form (in
which the secondary horizontal muri in the central
field tend to disappear). Poseidonamicus pintoi, new
species, is higher, relative to length, with a less conspicuous
ocular region and anterodorsal flange.
DIMENSIONS.—Length of holotype 1.09 mm,
height 0.67 mm; length of lower Miocene specimen
(USNM 174329) 0.85 mm, height 0.52 mm.
DISTRIBUTION.—Neogene of the southern Atlantic
and Indian Oceans. Oligocene in the northern Atlantic
(DSDP XII, 117).
Poseidonamicus minor, new species
PLATE 10: FIGURES 13, 14, 16, 17
HOLOTYPE.—Left valve, adult female (?), Plate 10:
figure 13 (USNM 174357); paratypes USNM 174358,
174359.
TYPE-LOCALITY.—Southeastern Pacific near (south
of) the Chile Rise in the vicinity of Downwind Expedition
station DWBG 74; lat. 28°43,S and long.
107°36'W, 3137 meters depth; bottom temperature
uncertain.
AGE.—Pleistocene to Recent; no specimens with
appendages were found.
DIAGNOSIS.—A coarsely reticulate species of Poseidonamicus
with excavate muri in which the massive
development of the reticulum, in particular the muri
running vertically over the carapace in the central
reticular field and the anterior (usually punctate)
field, has become preeminent to the exclusion of many
of the weaker longitudinal muri seen in other species.
The dorsal ridge is strong and a vertical ridge, not
seen in other species, is formed postjacent to the vertical
ridge joining the posterior ends of the dorsal and
ventrolateral ridges. Species is blind.
COMPARISON.—This species is the most robust of
those of Poseidonamicus known. The increase in the
development of some muri apparently relieves the
need of a reticulum with more mural strut members
(mural accommodation) as is characteristic of P.
major, new species, a slightly larger form. This species
is analogous in architecture to Bradleya andamanae,
new species, although not so small relative to others of
its genus and paradoxically (at least for the moment)
not typical of shallower water. It is premature to
define the range of morphology of this species. I am
not convinced that the simple factor of increased robustness
is sufficient to define P. minor. I have observed
a robust older form in cores from the South
Atlantic, but whose increase in mass within the muri
is arranged differently. Further study of these differences
in reticular pattern should yield profitable results.
DIMENSIONS.—Length of holotype 0.98 mm,
height 0.60 mm.
DISTRIBUTION.—Southeastern Pacific, deep ocean
floor (depth range not yet determined).
Poseidonamicus pintoi, new species
FIGURE 23, PLATE 10: FIGURES 7-12
ETYMOLOGY.—Named in honor of Professor Iraja
D. Pinto of the University of Rio Grande do Sul in
Brazil.
HOLOTYPE.—Left valve of adult male, Plate 10:
figure 11 (USNM 174355); paratypes USNM 174356.
TYPE-LOCALITY.—Continental slope off Brazil near
Rio de Janeiro in the vicinity of Albatross station
2763; lat. 24°17'S and long. 42°48'30"W, 671 fathoms
depth; bottom temperature 37.9° F.
AGE.—Recent of the central Atlantic.
DIAGNOSIS.—Distinguished from other species of
Poseidonamicus by its more quadrate outline; a nar54
SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
FIGURE 23.—Poseidonamicus pintoi, new species, adult female
(?): (A) exterior of the left valve (USNM 174355)
showing the pattern of the reticulum; (B) interior of the
same valve showing the hinge end and the duplicature; (c)
the hinge of the right valve; (D, F ) dorsal views of both
valves; and (E) the muscle-scar pattern. Scale •=• 100 microns.
rower anterior and posterior marginal flange, especially
in the ocular region; an even distribution of the
reticulation without specific differences in the emphasis
of certain muri (such as the vertical muri in the
posterior), but still with the generic pattern.
COMPARISON.—This species is as heavily reticulate,
but relatively shorter than Poseidonamicus major,
new species. It lacks the emphasis of vertical muri in
the central field of that species. It is near the shape of
P. minor, new species, but with many more reticular
elements. Those present are much less massive and
excavate.
DIMENSIONS.—Length of holotype 0.82 mm,
height 0.56 mm.
DISTRIBUTION.—Central Atlantic Ocean, continental
slope regions.
Poseidonamicus nudus, new species
FIGURE 24, PLATE 11: FIGURES 1-11
HOLOTYPE.—Left valve, adult; Plate 11: figure 5
(USNM 174351); paratypes, Plate 11: figures 1, 4
(USNM 174352).
TYPE-LOCALITY.—Mozambique Channel, western
Indian Ocean, in the vicinity of IIOE station 367G,
lat. 22°42,S and 39° 1 9% 3140 meters depth; bottom
temperature 1.85° C.
AGE.—Pleistocene to Recent; no specimens with
soft parts were found.
DIAGNOSIS.—A species of the genus Poseidonamicus
with only faint mural traces. The pattern of the reticulum
can be seen within the carapace wall by light
transmitted through the shell from below. The ventrolateral
carinae is present, though not pronounced.
The dorsal carinae is only faintly suggested by a
small-angled ridge in the posterodorsal region. Species
is blind.
COMPARISON.—This species is easily distinguished
because of its lack of expressed reticulation; however,
the late instars of samples found in the eastern Pacific
did have a subdued yet positive reticulum formed. It
is quite possible that the formation of a smooth carapace
may represent convergence. For the present,
however, all nude forms are considered as the same
species. The form is slightly smaller than P. major,
new species, and more elongate than P minor, new
species, or P. pintoi, new species. The wall structure
NUMBER 1 2 55
FIGURE 24.—Poseidonamicus nudus, new species; adult male
(?) : (A) exterior of the left valve with the pattern of the
reticulum, as seen in transmitted light, reconstructed on its
surface; (B) interior view of the right valve showing the amphidont
hinge, the thaerocytherid muscle-scar pattern and
the wide duplicative; (c) hinge of the left valve; dorsal
views of both valves. Scale = 1 0 0 microns.
of the valves has not yet been studied to determine
the cause of the loss of the reticulum.
DIMENSIONS.—Length of holotype 1.03 mm,
height 0.60 mm.
DISTRIBUTION.—Identified from the Indian Ocean
(type-locality) and the southeastern Pacific (near
Easter Island).
Family TRACHYLEBERIDIDAE Sylvester-
Bradley, 1948
Subfamily TRACHYLEBERIDINAE Sylvester-
Bradley, 1948
In 1967, Hazel proposed a division between the families
Trachyleberididae and Hemicytheridae on the
bases of differences in soft part anatomy and musclescar
morphology. He disagreed with Pokorny
(1964b), who considered the divided frontal musclescar
to have doubtful reliability as a taxonomic indicator.
Hazel (1967: 7) suggested instead that "the
great majority of hemicytherids have two or more
frontal (muscle) scars, whereas most of the Trachyleberididae
have a single frontal scar." He recognized
divisions within the Hemicytheridae (Hemicytherinae,
Thaerocytherinae, and Campylocytherinae) containing
various stages of frontal and adductor scar division.
In the Trachyleberididae he included the pterygocytherines,
the butoniines, and the cytherettines. All of
these forms have four undivided adductor scars and a
V-shaped frontal scar. He also included the Mauritsininae
and the Brachycytherinae with divided adductor
scars. The echinocytherines, which have a trachyleberid
anatomy (except for the so-called knee-joint
apparatus) and thaerocytherine (sometimes single)
frontal scars, were included as a new subfamily in
Trachyleberididae. These latter forms were considered
to have characteristics convergent with the hemicytherids
rather than being transitional.
Hazel cites 24 genera to be assigned to the nominal
subfamily of Trachyleberidinae suggesting some hesitation
to recognize as many subfamilies in this taxon
as he had in the Hemicytheridae. This reflects his
earlier assertion that the divisions among the Hemicytheridae
appear to be more "natural" than those of
the Trachyleberidae. One can also see this imbalance
reflected in the number of genera of the various
branches of his phylogenetic tree (five paired
branches have 2, 3, 5, 6, and 8, respectively) two
individual branches have 9 and 10, respectively) as
56 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
compared with the trachyleberine trunk (which has
24 genera).
Hazel's work is reviewed here to demonstrate an
important point—the absence, in the past, of appropriate
criteria to discriminate among subgroups
within the very large group of ornate trachyleberine
genera. The 24 genera, mentioned by Hazel, in fact
contain a proportionally large group of poorly understood
species, whose generic assignments are at best
insecure. Liebau's (1969) attempt to recognize species
groups on the basis of fossal patterns and pore conuli
is an important step in defining some of the necessary
criteria. Some of my observations (which include
study of about 50 patterns) agree with those of Liebau.
They were made independently of his study.
Therefore, our results do not necessarily agree.
The reticulate patterns are generally consistent
within the Trachyleberinae (where they can be observed
). I was skeptical that the same pattern would
be found within the Thaerocytheridae. I believe that
Cletocythereis rastromarginata (Brady) and C. haidingerii
(Reuss) (which have divided V-shaped frontal
scars) actually are only slightly modified trachyleberids.
The Cretaceous genus Limburgina Deroo,
which has a divided frontal scar (the lower part Ushaped),
has a reticulum that is trachyleberine and
yet has mural ridges like that of the bradleyines. This
group may represent, or be closely related to, the
ancestral stock of both families.
The individual pore conuli can be identified in
many nonreticulate trachyleberids (such as smooth
forms of Veenia). The pore conulus of Pokorny ("porenkegal"
of Triebel 1940) is only one of these. Although
the conulus itself may not always be evident,
many of the associated pores, which are distinct from
other normal and sieve pores in their positions and
relationship to the muri, are also recognizable in nontrachyleberids
Poseidonamicus (less so in Bradleya)
and Jugosocythereis (thaerocytherid), and Patagonacythere
(hemicytherid).
The positions of (and patterns formed by) the pore
conuli are subject to minor changes, but on the whole
they change less than do the patterns of the reticulum
and less than aspects of general shape or carapace
robustness. Those distal to the central region appear
to change in position or presence (among different
species) more than those closer to the central lateral
region of the carapace. These differences are thought
to reflect allometric change (change in proportion
due to ontogeny, dimorphism, adaptive modification)
in the general shape of the carapace. Comparisons
between the allometric changes, as reflected in pore
conuli pattern differences, and those of modifications
of the reticulum emphasize the role of mural compensation
(accommodation) in the general architecture
of the various forms.
Within the individual fossae often can be seen finer
muri (mural struts as well as secondary reticulation),
which can be observed to increase in intensity or add
fossae within a species. Liebau (1969) suggested that
the primary fossae can be recognized as homologous
sets containing the secondary reticulate subsets. It is
also true that some fossae seem to be excluded or new
ones appear between sets (perhaps depending on
what is defined as a set).
As the muri become thicker and consequently the
carapace becomes more robust, the number of muri
and fossae decreases. This is usually correlated with a
decrease in overall carapace size or changes in shape
in a particular sector of the carapace.
The median ridge ("mitte rippe" of Triebel 1940),
associated spines or tubercules, and other such major
topographic features of the carapace seem to arise
independently of either the pattern of the reticulum
or the pore conuli. Often the pore conuli are displaced
to the side of the median ridge, rather than
remaining on the crest. The reticulum seems to respond
to the form of these features, giving them
strength.
The muscle scars appear to "interfere" with the
continuity of the pattern of the reticulum. Muri can
be observed either to stop (forum) or bridge (ponticulus)
the region of the muscle-scar pattern, often in
quite different ways in different species or genera.
Those secondary architectural features must arise
from the original reticular pattern and are thereby
limited in the kinds of such structures that can form.
As the reticulum passes over the muscle scar node
the muri change in mass and structural form to accommodate
for the stress requirements imposed by
differences in shape and the "load" of this special
region of the carapace. In the Bradleyinae this accommodation
is often expressed as a bridge. In Agrenocythere,
new genus, and related forms it is expressed
as a radial structure called the castrum. The stresses
are transferred from the location of the scars to the
reticular fields by means of a truss system (the
bridge) or a reinforced radial grid (the castrum and
NUMBER 12
FIGURE 25.—Variation within the castrum among species of Agrenocythere, new genus. These
include (1) A. hazelae (van den Bold, 1946), Recent, Caribbean; (2) A. americana, new species,
Recent, Gulf of Mexico; (3) A. hazelae (van den Bold, 1946), Miocene, Trinidad; (4) A.
gosnoldia, new species; (5) A. pliocenica (Seguenza, 1880), with morphological terms, Pliocene,
Italy; (6) A. hazelae (van den Bold, 1946), Recent, eastern Pacific; (7) A. radula (Brady,
1880), Recent, Indian Ocean; (8) A. spinosa, new species, Recent, Indian Ocean; (9) A. hazelae
(van den Bold, 1946), Miocene, South Atlantic. Note the consistency in the basic pattern of
the muri, yet how the arx becomes strongly developed, especially in the variations of A. hazelae
in different regions in different ages.
58 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
arx). From a utilitarian standpoint, it is fortunate
that because the carapace usually breaks around this
structure (responding to its increased strength), fragments
containing the castrum can be used for species
identification (with difference in castral architecture).
Since specimens are rare in deep-sea samples, this
aspect of Agrenocythere morphology proves to be especially
advantageous.
A bold enlargement of the muri over the musclescar
node at the center of the castrum is often the
most conspicuous feature of the castrum, sometimes
extending from its central part in the region of a large
spine (specula) to its outer mural ring (rampart) and
in one case (Miocene, South Atlantic A. hazelae)
even to the mural series beyond this ring. The architecture
of the castrum does not always include a parapectus
(raised outer murus; see pages 58, 59). Often
pore conuli surmount the castral rampart without an
enlargement. In Figure 25 nine variations of castral
architecture are shown that occur among some of the
various species of Agrenocythere. The descriptions
and significance of these changes will be given in
more detail in the discussion in the next section.
Genus Agrenocythere, new genus
ETYMOLOGY.—Greek agrenon, net.
TYPE-SPECIES.—Agrenocythere spinosa, new species.
DIAGNOSIS.—Distinguished from other reticulate,
holamphidont trachyleberine genera by its large size,
its usually produced and upturned posterior, the absence
of an eye tubercule and the development of a
circular and radial complex (castrum) in the design
of the reticulum over the muscle-scar node reinforced
by mural thickening near the center (the arx) or
around its outmost ring (the parapectus). The posterodorsal
region is marked by a dorsal bullar series,
which distinguishes this genus from those with long
dorsal carinae. The system of intramural pore conuli
includes one emphasized in the posteromedian region
(Charon), another in the position of the "porenkegal"
(Leo) and a third on the posterior margin (Terminus)
. The appendages are attenuate.
GENERAL OUTER CARAPACE MORPHOLOGY.—The reticulum
can be divided (Figure 8) into character
complexes and reticular fields. The character complexes
include (1) the marginal rims, (2) the ventrolateral
carina, (3) the dorsal bullar series, and (4) the
castrum. Between these complexes lie the reticular
fields, which are simply designated by location or region
of the carapace. Agrenocythere and several other
genera are characterized by that part of the reticulum
that surrounds and surmounts the muscle-scar node,
the radial structure called the castrum.
The castrum (Latin, fort) consists primarily of an
outer mural ring (rampart) that defines the outer
boundaries of twelve fossae (numbered clockwise, one
through twelve) of the ballium. Often portions of
the rampart murus are enlarged or raised to form a
parapectus, which usually includes one of the principal
pore conuli. There may be several parapecti. If
the muri of the inner castrum (inside the ballium) are
raised, they form a conspicuous, often H-shaped structure
called the arx (inner or principle fort). The arx
is usually surmounted by a prominent spine (the
specula; watchtower), approximately at the center of
the castrum. The arx may be confined to the center
of the castrum and surrounded by a relatively open
mural ballium and rampart system. There may be
parapecti, or some of the parapecti (usually in the
region of ballial fossae 9-12) may be joined to the
arx enlarging its extent (thereby being considered an
integral part of it). Within the center of the arx is a
fossa termed the fossa arcis, containing a characteristic
sieve pore, the porus castri. Just dorsal to the
fossa arcis is another fossa, the pervial fossa, which
is often open and exposed to the dorsal reticular field.
To the posterior of the arx and just beneath the
specula lies the forum, which is a smooth region
formed by interference of the adductor muscle scars
(the crystal prisms are frequently visible from the
exterior) with the reticulate pattern of the castrum.
The terms delineating these important features were
chosen because of the similarity in form of the overall
structure to an ancient fortification (especially impressive
in stereo-SEM view), and to make them easy to
remember. This terminology also seems appropriate
as this structural system seems to lend strength to the
central lateral part of the carapace.
The remainder of the reticulum, or the reticular
field, extending from the rampart of the castrum outward
toward the margins of the valve is intermittently
punctuated with pore conuli. These features are
formed by a series of normal, usually conjunctive,
intramural pores. Each individual egress of a pore
from the carapace is marked by a raised rim forming
a volcano-like pore conulus. In the absence of a conulus,
the murus is notably raised and widened to acNUMBER
12 59
commodate the pore, which is almost always there if
preservation of the carapace is adequate. Of the few
specimens examined that still had setae attached to
the carapace, none were observed by me to have these
emerging from the pore conuli. I cannot state with
assurance that they had none when the animals were
alive. It is noteworthy that the pore conuli are located
on the muri between fossae. Many of the fossa contain
solar sieve pores. These may indicate a relationship of
the fossa to cells deeper within the soft tissue, dermal
layers underlying the carapace. There may be a direct
correlation between the pattern of the carapace secreting
the sensory epithelium, and the pattern of the
reticulum and distribution of solar sieve pores. As
noted by Liebau (1969), the locations of the pore
conuli appear to be constant within a yet unknown
but significant range of different genera and species
(Plates 3 and 4).
I do not find the numerical system of fossal or pore
conulus identification suggested by Liebau to be as
useful as I would like. These descriptors are not sufficiently
neutral. Although the terms are serial, their
placement is not. There is a lack of consistency of the
serial alignment between some species. Perhaps at a
later time a system of enumeration, consistent with
development can be devised, but until that time I find
proper names or zone coding (color or nomenclatural)
easier to use and remember.
The terminological scheme for the pore conuli I
have used here is based on reference of the position of
the individual conulus relative to the castrum (on the
left valve). The ballium is usually divided into 12
parts of fossae and can be consistently enumerated in a
clockwise direction or in the manner of a circular
calendar. The pore conuli closest to the ballium can
be identified relative to its closest ballial fossa (Figures
8, 25). I have indicated them by use of signs of the
zodiac, which are at least known en passant by most.
Farther away from the castrum short names of Greek
origin (proper names of letters or mythological characters)
are used and chosen to suggest relationship to
the anterior and posterior margin. These terms will be
used in the following discussion. They are open in the
sense that more can be added or some subtracted
without prejudicing the rest.
The marginal rim is best developed on the broadly
rounded anterior and the caudate posterior of the
carapace. It is present along the ventral margin but
less conspicuous. It is best developed in Agrenocythere
gosnoldia, new species, and least developed in the
Caribbean forms of A. antiquata, new species. The
emphasis with which it is expressed is also reflected in
the massiveness of the ventrolateral ridge, and the
dorsal bullar series. The massiveness of these features
influence the general outline of the animal. They are
relatively narrow or confined in Agrenocythere radula,
become broader and sharpened in A. hazelae, to
blunted and somewhat massive in A. americana, new
species, narrow in A. pliocenica, and exaggerated
(broad) in A. gosnoldia.
The dorsal bullar series, which consists of two or
three dorsally produced portions of the reticulum,
may be a series of nodes as in A. americana, or tuberculate
complexes as in A. hazelae, or form a punctuated,
crested ridge as in A. gosnoldia, or be diminished
as in A. radula.
The ventrolateral ridge is a very prominent feature
in all species of Agrenocythere. It is often ponticulate
with fenestra joining the ventral and lateral regions of
the carapace. There are pores at the junctions of the
ridge and their supporting struts, and often there are
also conjunctive spines and a large terminal spine.
The extension of this ridge as a skidlike support is
reflected in the increase in mass of the muri that join
this feature to the rest of the reticulum.
Both the mass and the spinosity of the reticulum
differs among species. Whereas none of the forms
described could be considered delicate, the muri of
Agrenocythere radula and A. pliocenica are not as
massive or not as high in relief relative to the solar
width in contrast to the considerable relief of A. hazelae.
The regularity of pattern of the reticulum varies
also, perhaps related to the massiveness of the rest of
the carapace (Plates 5 and 6). The junctions of the
muri forming the reticulum of some Agrenocythere
species are surmounted with small spines (conjunctive
spines), however only a few of these are pore conuli.
Spines, some with pores, line the marginal rims and
ventrolateral ridge with some variation in number
and size among species. Celate spines are seen in some
specimens of A. radula and A. gosnoldia, especially in
the anterior (in the B fossal series). Celation of the
muri in the anterior may be related to the development
of the formation of additional intrasolar muri
within the anterior fossae of forms such as A. radula
and A. pliocenica.
INTERIOR CARAPACE MORPHOLOGY.—In general the
60 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
FIGURE 26.—Agrenocythere spinosa, new species; the designated
type-species; adult, female (USNM 174366): (A) exterior
of the left valve with the order of the fossae in the
ballium and the locations of the pore conuli indicated; ( B )
the exterior of the right valve; (c) the interior of the right
valve showing the terminal tooth elements of the holamphidont
hinge, the features of the duplicature, and the trachyleberid
muscle-scar pattern; (D) the interior of the left valve.
Scale = 1 0 0 microns.
interior of the carapace is typical of others found in
trachyleberine genera (Figure 26).
Hinge: Holamphidont (Figures 8c, 26c, D ) .
Muscle-scar Pattern: Four undivided adductor
scars, simple mandibular scar, V-shaped frontal scar,
prominent dorsal scar (Figure 8D) .
Duplicature: Wide, "welded," no vestibule.
Radial-pore Canals: Simple, approximately 20 in
the anterior, 10 in the posterior.
APPENDAGE MORPHOLOGY.—The following description
of the soft part anatomy of Agrenocythere is
based on the dissection of a female specimen of A.
radula (Brady), USNM 174384-5; from Mozambique
Channel (IIOE 407A, dissection 382, Figure 27).
The first antennae are divided into six segments
with podomeres v and vi (following the scheme of
Miiller 1894) being unfused. The second antennae are
long and narrow with an abbreviated exopodite. The
mandible has a "five-fingered" epipodite (trachyleberid
characteristic) and two brushlike major setae.
The thoracic appendages are serially similar without
modification of the first legs. They are long and reinforced
("knee apparatus"; considered a hemicytherid
characteristic) at the knee; a basal proximal carrotlike
bristle is present on the anterior two prodopodites.
The appendages of Agrenocythere like many other
deep-sea ostracodes have attenuated and cirrose aspects.
To what extent these are primarily phyletic or
adaptive is not yet understood (see pages 30-31). It is
possible, however, that primitive divisions of appendages
are perpetuated in a low mechanical energy
environment. The stronger adaptive forms of shallower
water (greater cross-sections relative to length,
fewer segmental divisions) is a recent specialized development
peculiar to more agitated waters, coarse
and unstable bottoms.
COMPARISONS WITH OTHER GENERA.—Of the reticulate
trachyleberine genera thus far described Oertliella
and Cletocythereis are most similar to Agrenocythere.
Comparison between the type-species of Oertliella
{O. reticulata; Plate 5: figures 5, 6) and Oertliella
aculeata (Figure 6D) can be made with the
species of Agrenocythere. given here (Figures 6, 7;
figures on Plate 6). The patterns of the reticulum
and of the pore conuli are substantially the same.
The castral regions of Oertliella (see examples at the
end of this report) are without an arx even though a
specula and adjacent spine are present. Oertliella has
NUMBER 12 61
FIGURE 27.—Appendages of female specimen (USNM 174384, 174385) of Agrenocythere radula
(Brady, 1880) from Mozambique Channel (IIOE 407A; dissection 382) : (A) the first antennae;
(B) the second antennae; (c) the thoracic appendages; and (D) the mandible. Scale = 100
microns; roman numerals refer to the segmentation system of Miiller, 1894, ka = knee apparatus,
ex = exopodite, ep = epipodite.
62 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
a prominent eye tubercule which Agrenocythere does
not. The specimens of Oertliella ducassae that I have
described from the Bartonian of the Biarritz section
have a long, accentuated, dorsal crest similar to the
male (?) of O. reticulata. The distinction between the
two groups may lie in the adaptive differences in
morphology that became stabilized during the Paleogene
with Oertliella remaining smaller and robust
with eye tubercules and a long dorsal ridge, while
Agrenocythere became larger, more embellished with
detail along the dorsum and in the castral region, and
blind. Oertliella aculeata represents a problem in this
classification as it has characteristics of both Oertliella
and Agrenocythere. It is compressed in size with exaggerated
pore conuli, dorsal bullae, and ventrolateral
ridge, compared to O. horridula or any of the Agrenocythere
species. It has no castral arx and has an eye
tubercule.
Trachyleberidea and Hazellina also have aspects of
general resemblance to Agrenocythere although they
are much smaller, often more attenuated (especially
toward the posterior) and have developed more massive
posterodorsal ridges or partial median ridges.
Their castral regions are not well developed and although
the reticular pattern remains the same, there
is no arx or other such features. The reticulum of
these genera is frequently celate, which rarely is seen
in Agrenocythere. Many of the pore conuli are present
in all three genera, but more study is required to
examine how stable this latter system is in Trachyleberidea.
Liebau (1969) has illustrated similarities in fossal
patterns between Oertliella aculeata, Cythereis longaeva
longaeva, and Limburgina ornata. He identified
O. aculeata as the subspecies horridula including
Bosquet's species in aculeata. I believe this is an error,
and that horridula is not only a separate species but
much closer to O. ducassae and therefore a truer
Oertliella. He refers to the more or less primitive type
of "limburginotypes ornament" in which he would
include the type of Oertiella {O. reticulata (Kafka)),
O. gr. horridula aculeata (Maestrichtian-Paleogene)
and several other species. I am sure he would have
included Agrenocythere species also, had they been
available. In my opinion this grouping has merit in
that it does recognize the similarities in fossal pattern,
but I believe that it also overlooks important differences
in the pattern of the reticulum itself. As discussed
elsewhere Limburgina also has a strong resemblance
to older Bradleya species. The divided
frontal scar, which may simply be a breakup of the
V-shaped scar, shows the morphological instability of
this complex of forms near the Mesozoic-Cenozoic
boundary.
Many features of the reticular pattern of Agrenocythere
can be traced to reticulate variants of Cythereis
ornatissima Reuss. Comparison of the similarity in
pattern can be made by inspection of figures 1 to 8 of
Plates 3-6, especially figures 2 of Plates 3 and 5.
Cythereis ornatissima is quite variable even within a
given population; however, the major differences between
this form and that of most Agrenocythere species
is the proximal compression and distal distention
of the pattern of the reticulum and spinose marginal
features of the former. The median ridge ("mitte
rippe") often considered typical of Cythereis and
Cytherew-like forms (Triebel 1940) is not always present
within a single Cythereis species population.
There is often a retention of only the pore conulus
Charon as is also characteristic of some species of
Agrenocythere.
It is still premature to offer comparisons between
other reticulate trachyleberine genera such as Costa,
Reticulocythereis, or Chrysocythere as these genera,
especially the former as it is known in the western
hemisphere, are in a confused state.
Cletocythereis also has reticular and pore conuli
patterns like Agrenocythere. Its castrum is relatively
unadorned with reticular structures, such as a specula
or arx. The ventrolateral and dorsal carina are massive
and elongate. The caudal process may become
exaggerated in the male as in some species of Agrenocythere.
The frontal muscle scar is V-shaped; however,
it is becoming divided. This division is sometimes
complete and apparently is a parallel trend to
that division occurring in the Thaerocytheridae.
INCLUDED SPECIES
Agrenocythere spinosa, new species; Mozambique Channel,
Recent, designated type-species.
A. radula (Brady, 1880) ; Indian Ocean; Pliocene to Recent.
A. hazelae (van den Bold, 1946) ; Caribbean, Atlantic, and
Mediterranean; Oligocene to Recent.
A. americana, new species; Gulf of Mexico; Recent.
A. pliocenica (Seguenza, 1880) ; Mediterranean, Pliocene-
Early Pleistocene.
A. gosnoldia, new species; western North Atlantic; Eocene.
A.? cadoti, new species; Southern Ocean off Australia.
A. antiquata, new species; Europe, Caribbean; Paleogene.
NUMBER 12 63
FIGURE 28.—Stereophotomicrographs of the holotype (USNM 174339) of Agrenocythere spinosa,
new species, the type-species, from the Recent of Mozambique Channel (IIOE 407D) as
seen from left lateral, and left anteroventral oblique views (x50). Also see Figure 26 for drawings
of other views.
64 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
FIGURE 29.—Stereophotomicrographs of the castrum of the holotype of Agrenocythere spinosa,
new species (x200).
Agrenocythere spinosa, new species
FIGURES 26, 28, 29; PLATE 3: FIGURE 7;
7; PLATE 12; PLATE 14: FIGURE 5.
PLATE 5: FIGURE
HOLOTYPE.—Left valve, adult female; Figures 28,
29 USNM 174339; paratypes USNM 174336, 174365,
174366.
TYPE-LOCALITY.—Indian Ocean, Mozambique
Channel off western Madagascar in the vicinity of
IIOE Station 407D; lat. 17°32'S, long. 43°15'E, 1360
meters depth; bottom temperature 4.5° C.
AGE.—Recent; no specimens containing appendages
were found.
DIAGNOSIS.—Distinguished from other species of
Agrenocythere, new genus, by a prevalence of elongate
and often complicate conjunctive and marginal
spines, a narrow and ponticulate ventrolateral ridge,
conspicuous rimmed solar sieve pore canals and simple
and delicate muri. The arx of the castrum is well
defined toward the dorsal rampart only, with the fossa
arcis remaining open toward the pore conulus Leo.
The pore conuli Capricornus, Scorpio, and Leo surmount
the castral rampart without extension of a
parapectus. The second bulla (b) of the dorsal bullar
series is attenuated by a large hollow spine.
COMPARISONS.—Some remarks of comparison of
the type-species with others of the genus is also given
in the general section on comparative morphology of
the genus. The castral arx is not massive and confined
to the central part of the castrum, being weak in the
ventral part compared to that of A. hazelae. It lacks
the connecting muri to parapectal elements on the
rampart. It lacks the uniformity of reticular pattern
in the posterior characteristic of A. radula. Its spinosity
is greater than any of the other species.
DIMENSIONS.—Length of the holotype 1.32 mm,
height 0.77 mm.
DISTRIBUTION.—Western Indian Ocean. The stations
where both Agrenocythere spinosa and A. radula
were found are shown in Figure 30. It is notable that
A. spinosa is consistently found closer to shore and in
shallower water than A. radula. Of the 24 stations
from which specimens were obtained, the 11 with A.
spinosa were predominantly from waters from 400 to
1600 meters and 13 with A. radula were predominantly
from 1000 to more than 3000 meters depth.
Both species seem to be concentrated in greatest number
of specimens at depths of from 1200 to 1600
meters.
Agrenocythere hazelae (van den Bold, 1946)
FIGURES 31-38
Cythereis hazeli van den Bold, 1946:92, pi. 10: fig. 4a-c.
Trachyleberis? hazelae (van den Bold).—van den Bold
1957:241, pi. 1: fig. 11; 1960:165.
NUMBER 12 65
0°
O A. radula
• A. spinosa
-10°
- 5°
-15°
h20°
-25°
-30°
FIGURE 30.—Localities in the region of the Mozambique Channel (separating Madagascar and
mainland Africa) in which Agrenocythere radula (Brady, 1880) (circles) and A. spinosa, new
species, (dots), were found. A. radula was generally found to occur in the deeper regions away
from the slope areas frequented by A. spinosa (see p. 64).
66 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
FIGURE 31.—Stereophotomicrographs of * hypotype (USNM 174345), an adult, female left
valve, of Agrenocythere hazelae (van den Bold, 1946), from the Recent of the eastern Caribbean
Sea (ALB 2751), as seen from left lateral, and left anteroventral oblique views (x 50).
NUMBER 12 67
FIGURE 32.—Stereophotomicrographs of the castrum of a hypotype of Agrenocythere hazelae
(van den Bold, 1946) (same specimen as Figure 31, x200).
Hermanites(?) hazelae (van den Bold).—Ruggieri 1960:3,
pi. 1: fig. 8.
"Bradleya" hazelae (van den Bold).—van den Bold 1968b:
66, pi. 3: fig. 6.
Not Bradleya hazelae (van den Bold).—Ascoli 1969:54.
?Trachyleberis reticulospinosa (van den Bold).—van den
Bold 1957:241, pi. 1: fig. 10 [instar?].
Not Trachyleberis reticulo spinosa (van den Bold).—van den
Bold 1946:100, pi. 6: fig. 18.
ETYMOLOGY.—Named for Hazel van den Bold {hazelae),
but gender originally in error {hazeli in van
den Bold 1946).
HOLOTYPE.—A right valve from the lower Miocene
of Cuba (Tchopp locality 1479 in van den Bold 1946;
table 1) ; reposited in the Mineralogist-Geologish Instituut
of the State University of Utrecht (Cat. No.
SI3015) ; originally described and illustrated in 1946
(van den Bold, page 92: pi. 10: fig. 4), later designated
by van den Bold (1968: 66) as holotype.
Length of holotype 1.15 mm, height 0.61 mm (van
den Bold 1946: 92).
TYPE-LOCALITY.—Lower Miocene of Cuba, East
Oriente Province, Tchopp locality 1479; age originally
given as Oligocene now considered lower Miocene
by van den Bold (personal communication).
DIAGNOSIS.—Agrenocythere hazelae (van den
Bold) is distinguished from other species of the genus
by its more rugose appearance, which includes the
accentuation of the castrum to form a strong arx that
extends to include the parapectus of the 9 through 12
ballial fossae; the ventrolateral ridge is prominent, the
dorsal bullae are accentuated and robust, and the
fossae in the posterior median region are not as well
ordered as they are in other species. The species is
blind.
COMPARISONS.—Agrenocythere hazelae has more
subdued marginal rims and is generally larger (geologically
younger populations) than A. gosnoldia, new
species. Its reticulum is considerably less ordered than
A. radula whose muri may also be celate with spines,
whereas A. hazelae has only been observed to be celate
with flanges (forming strongly excavate muri).
The marginal and conjunctive mural spines of A.
hazelae are absent, diminished, or knobby compared
to the more complicate spines of A. spinosa, new
species. A. americana, new species, is much more massive
with greater reticular regularity by comparison.
A. pliocenica is often larger with finer, simpler muri
and lacks the rugose aspect. A. hazelae is larger and
its reticulum more developed (muri better defined
and higher) than A. antiquata, from which it may
have evolved. It also developed the castral arx which
is blunted in A. antiquata, new species.
68 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
FIGURE 33.—Castral region of right valve (same specimen as
shown in Figure 34) of Agrenocythere hazelae (van den
Bold, 1946) from the eastern Pacific (xl50).
DISCUSSION.—The generic assignment of Cythereis
hazelae (nee hazeli) has been troublesome from the
beginning of its description, as is reflected in the
above synonymy. The assignment of this species to a
new genus was first proposed by Ruggieri in 1960,
and later by van den Bold in 1968(b). It was for a
different reason, however, that the present new genus
Agrenocythere was first considered. The concurrence
of morphologic similarity between newly discovered
specimens of the Recent species Cythere radula Brady
and the new species A. spinosa with "Bradleya" pliocenica
Seguenza prompted a search for Atlantic relatives
which led to examination of "Cythereis" hazelae.
Fortunately, the discrimination between Bradleya dictyon
(Brady, 1880) and Agrenocythere radula (Brady,
1880) is pronounced in deep-sea forms and this problem
which concerned previous authors, was avoided.
The problem not avoided unfortunately, as discussed
by Ruggieri (1960), is the relationship of the "hazelae
form groups" with other genera in the Trachyleberididae.
This subject is discussed elsewhere.
Specimens of Agrenocythere antiquata, new species,
from the lower and middle Eocene of Europe and
America, are typically of medium size (often slightly
more than 1000-1100 microns in length) with suppressed
detailed features but enlarged feature complexes.
One notes these aspects in the two specimens
of similar but not identical age (middle and late
Eocene) from Trinidad (Figure 55) and Italy (Figure
54). In both forms the castral, bullar, and ventrolateral
ridge regions are produced as is the pore conulus
Charon. The rest of the muri are subdued and the
carapace is in general spineless. The arx later becomes
developed in the anterodorsal sector of the castrum
and is typical of the younger descendant species A.
hazelae, but the specular region of A. antiquata is
most prominent and projects as a massive bosslike
tubercule.
During the Oligocene and early Miocene, the size of
the carapace of Agrenocythere antiquata-hazelae species
complex increases slightly and the reticulum begins
to be more robust throughout the extent of the
muri. Details of the castrum become sharper and in
some cases by middle Miocene may become exaggerated
(Figures 35 and 36) while in others (Figure 25)
may simply become enlarged. The dorsal bullae are
produced and no longer butte-like. Conjunctive and
marginal spines are developed in younger forms.
Comparison between Recent forms (Figures 31,
32) of A. hazelae from the Caribbean with the Recent
forms from the Pacific (Figures 33, 34, Plate 13;
figures 7-11) shows much less change has occurred
between these forms than in the Atlantic alone. It is
not known when the Pacific form emigrated from the
Caribbean region, but it does not share the distally
enlarged arx as a common feature with the eastern
forms, especially those of the South Atlantic. It is
similar in almost every other respect, however, and is
less extreme in morphologic departure from the stock
forms than are some of those which had geographic
and chronistic continuity. The one aspect in which it
does differ is in size with the Pacific specimens being
25 percent longer (1.4 mm versus 1.1 mm) than the
Caribbean and Atlantic specimens. With the few specimens
available it seems inadvisable to erect a new
species on such minor morphological grounds even
though genetic continuity may have been broken some
time ago.
The evolutionary change that may have taken
place in Europe between Miocene remnants of
Agrenocythere hazelae and the developing A. pliocenica
is still a matter of conjecture. Ruggieri (1960)
reported Sicilian Miocene representatives of A. hazelae,
and I have Miocene specimens collected near
Ancona, Italy, and sent to me by Ascoli. Also, I have
post-Mcssinian specimens of A. pliocenica. Yet the
NUMBER 12 69
FIGURE 34.—Stereophotomicrographs of an eastern Pacific hypotype (USNM 174347), an adult,
female right valve, of Agrenocythere hazelae (van den Bold, 1946), from the Recent of the eastern
Pacific (Malpelo Rise; ALB 3375) as seen from left lateral, and left anteroventral oblique
views (x50). For other illustrations of other specimens see Figure 33, Plate 13: figures 7-11, and
Plate 14: figures 7-9.
70 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
gIBf' w^ • *$-
FIGURE 35.—Stereophotomicrographs of a hypotype (USNM 174337), an adult, female left
valve of Agrenocythere hazelae (van den Bold, 1946) from the Cipero formation (middle Miocene)
of Trinidad (RM 15715) as seen from the left lateral, and left anteroventral oblique views
(x70).
NUMBER 12 71
FIGURE 36.—Stereophotomicrographs of the castrum of a Miocene hypotype from Trinidad
(same specimen as in Figure 5) of Agrenocythere hazelae (van den Bold, 1946) (x200).
FIGURE 37.—Stereophotomicrographs of the castrum of a Miocene hypotype (same specimen as
in Figure 38) of Agrenocythere hazelae (van den Bold, 1946) (x200).
72 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
FIGURE 38.—Stereophotomicrographs of a. hypotype (USNM 174344), an adult, female left
valve, of Agrenocythere hazelae (van den Bold, 1946) from the Miocene of the South Atlantic
(DSDP III 14, core la, section 3) as seen from the left lateral, and left anteroventral oblique
views (x75) ; showing the anterior development of the castrum into the anterior field.
NUMBER 12 73
nature of the transition between the species, if indeed
one existed, is not clear. More material of late Miocene
age is required before the solution of this problem
is reached. Further discussion of this problem is
given in the section on A. pliocenica and has been
mentioned in the introductory section on evolution of
this group.
DISTRIBUTION.—Agrenocythere hazelae is the most
widely distributed, stratigraphically long ranging, and
the most variable of the known Agrenocythere species.
It is probably the central stock from which most, if
not all, Neogene species in the Atlantic and Mediterranean
have been derived. First described by van den
Bold in 1946 from the lower Miocene (first considered
Oligocene) of Cuba, it has been widely reported
by him from other regions in the Caribbean (although
his identifications of Paleogene specimens
would have included the new species now called A.
antiquata). It was reported from Europe by Ruggieri
in 1960 from the Miocene (Ragusano section) of Sicily
(reported later erroneously by Ascoli (1969) from
the Eocene of northeastern Italy). It is now reported
from the south Atlantic near the Tristan da Cuhna
Islands, and from the middle and late Tertiary from
the Caribbean region. No Pleistocene or younger specimens
have been reported from the open Atlantic;
however, it has been found in Recent sediments in the
Caribbean and in the eastern Pacific. Its presence in
the eastern Pacific poses a problem in the explanation
of how it got there. As a typically deep-water form it
is supposed that a deep-water passage across or
around the Isthmus of Panama region was required.
Its comparative lack of similarity with South Atlantic
species suggests that it did not immigrate into the
Pacific from this area.
Agrenocythere americana, new species
FIGURES 39-41; PLATE 14: FIGURES 6, 10-15; PLATE 4:
FIGURE 7; PLATE 6: FIGURE 7
HOLOTYPE.—Left valve, adult male, Figures 40, 41;
USNM 174348.
TYPE-LOCALITY.—Gulf of Mexico, southeast of the
Mississippi River Delta in the vicinity of U.S. Fisheries
R /V Albatross station 2383; lat. 28°32'N and
long. 88°06'W; depth 2160 meters; bottom temperature
4.3° C.
AGE.—Recent; no living specimens were found.
DIAGNOSIS.—Distingiushed from other species of
FIGURE 39.—Agrenocythere americana, new species, adult,
female (USNM 168381) : (A) exterior of left valve with the
order of the fossae in the ballium and the locations of the
pore conuli indicated; (B) the interior of the right valve
showing the muscle-scar pattern and the holamphidont hinge
elements; (c) the hinge elements of the left valve; (D, E) the
right and left valves as seen from dorsal view. Scale = 100
microns.
74 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
FIGURE 40.—The castral region of the holotype of Agrenocythere
americana, new species (same specimen as shown in
Figure 41; xl50).
Agrenocythere, new genus; by the general absence of
marginal and reticular spines, a massive ventrolateral
ridge, simple massive (often distally enlarged) muri
and a rounded to tapered posterior. The arx of the
castrum has been noted to be divided into an Hshaped
upper portion lying between the pervial fossa
and the fossa arcis (containing the specula) and a
lower part underlying the fossa arcis and extending to
form a parapectus between pore conuli Scorpio and
Capricornus. The rampart extending from pore conulus
Leo may be developed into a parapectus but as the
muri in this area are generally massive, definition of
this particular feature is difficult. The second bulla
(b) and third bulla (c) of the dorsal bullar series are
both massive and butte-like as is the ocular node.
COMPARISONS.—The general aspect of Agrenocythere
americana is one of greater massiveness in the
reticulum than with the other species. It is closest to
A. antiquata, new species, in this respect; however,
this latter species has prominent character complexes,
whereas they are more subdued into a generally regular,
even slightly celate (in the anterior) reticulum of
A. americana. The ventrolateral carina is ponticulate
with the suspended segments rounded to blade-like,
somewhere between the angled blade of A. hazelae
and the columns of A. spinosa, new species. The dorsal
bullar series is massive but not prominent. The
posterior marginal rim is more bluntly rounded than
the other species which may be produced to attenuated.
The castral arx bipillar is in the form of an
"H" rather than radiate. It is simple like the more
conservative forms of A. hazelae or like A. pliocenica.
There is a general overall similarity with some specimens
of A. pliocenica (especially from the Trubi formation
of Sicily) except in the posterior, which is
more tapered in A. americana due to the absence of
the posterodorsal angle of A. pliocenica.
DIMENSIONS.—Length of holotype, male, 1.32
mm, height 0.73 mm; length of paratype, female, 1.25
mm, height 0.73 mm.
DISTRIBUTION.—Recent of Gulf of Mexico.
Agrenocythere radula (Brady, 1880)
FIGURES 42, 43; PLATE 13: FIGURES 1-6; PLATE 14:
FIGURES 1-4, 16-18
Cythere radula Brady, 1880: 102, pi. 19: fig. 4a, b.
LECTOHOLOTYPE.—Designated herein, British Museum
specimen (BM 81.5.28), collected from Challenger
station 191A (Plate 14; figures 16-18).
TYPE-LOCALITY.—Vicinity of Ki Islands, southern
Indonesia; lat. 5°26'S, long. 133°19'E; 580 fathoms
depth; bottom temperature 4.9° C.
AGE.—Pliocene to Recent.
DIAGNOSIS.—Brady (1880) originally was struck by
the sculptural pattern of Cythere radula which he
compared to that of C. arachnoidea Bosquet [now
Oertliella aculeata (Bosquet)]. We find now that in
fact Agrenocythere radula (Brady) has a very regular
reticular pattern (more so than O. aculeata although
admittedly very similar), which distinguishes it from
all of the other Agrenocythere species. The muri in
the posterior region are aligned into opposed crossed
systems. The intersections of the muri are often
marked with conjunctive spines or conspicuous pore
conuli. The muri are often celate. The ventrolateral
ridge is not conspicuous except for the serially arranged
spines. The dorsal bullar series is subdued except
for a prominent posterior spine (c). The castrum
is open and regular with a prominent specula. The
FIGURE 41.—Stereophotomicrographs of the holotype
(USNM 174348), an adult, male left valve, of Agrenocythere
americana, new species, from the Recent of the Gulf of
Mexico (ALB 2383), as seen from left lateral, and left anteroventral
oblique views (x50). For light photographs of other
specimens see Plate 14: figures 6, 10-15.

76 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
FIGURE 42.—Stereophotomicrographs of a hypotype (USNM 174362) of Agrenocythere radula
(Brady, 1880), from the Recent of Mozambique Channel (IIOE 407D) as seen from the left
lateral, and left anteroventral oblique views (x50).
NUMBER I 2 77
FIGURE 43.—Stereophotomicrographs of the castrum of Agrenocythere radula (Brady, 1880)
(x200), same specimen as in Figure 42).
arx is subdued and one must look hard to imagine
parts of it to be present at all. Because Brady's species
was founded on one specimen, a late instar, this
represents the first diagnosis that includes consideration
of variation and also comparison with related
forms.
COMPARISONS.—This is one of the more extreme
member species of the genus. The regularity of the
reticular and fossal patterns is pronounced in the alignment
of its elements, in columns in the posterior and
radially in the anterior. The castrum is also radiate
from the specula with the arx (characteristic of the
Atlantic derived forms) diminished to almost absent.
The dorsal bullar series is produced as spines, rather
than strong bullae, and bulla B is enlarged or attenuated,
often oriented toward the posterior. This same
feature (the "cocked" B dorsal bulla) is also found in
A. spinosa and in some variants of A. hazelae (which
may also have A bulla "cocked"). The ventrolateral
carina is composed of short small support mural struts
and thin connecting columns or ridges fused against
the main carapace wall. It is not generally fenestrate.
For illustrations of appendages see Figure 27.
DIMENSIONS.—Length of hypotypes 1.39 mm and
1.42 mm; height 0.77 mm and 0.79 mm.
DISTRIBUTION.—Indian Ocean and Indonesia; Pliocene
to Recent.
Agrenocythere pliocenica (Seguenza, 1880)
FIGURES 44-50; PLATE 3:
3, 4
FIGURES 3, 4; PLATE 5: FIGURES
Cythereis pliocenica Segeunza, 1880:192.
Cythereis dictyon pliocenica Seguenza.—Ruggieri 1953:78,
pi. 2: figs. 10-10d, 11.
Bradleya dictyon pliocenica (Seguenza).—Ruggieri 1959:
186; 1960: 4, pi. 1: fig. 5.
Bradleya pliocenica (Seguenza).—Ruggieri 1962:21, pi. 1:
fig. 22.—Colalongo 1965:91, pi. 11: fig. 1.
AGE.—Pliocene to early Pleistocene; Italy.
DIAGNOSIS.—Distinguished from other species of
Agrenocythere, new genus, by the absence of reticular
spines, a broad blade-like ponticulate ventrolateral
ridge, a tendency toward subdivsion of the fossae in
the anterior reticulum, simple yet conspicuous muri, a
somewhat more elongate overall shape and a consequent
enlargement of the fossae in the postmedial
region. The arx of the castrum encompasses the fossae
arcis yet remains discrete from the rampart, which is
generally featureless except for a bold parapectus extending
several ballial fossae from pore conulus Leo.
The pervial fossa may be semi-enclosed. The second
78 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
bulla (b) of the dorsal bullar series is often blade-like
and prominent.
COMPARISONS.—The reticulum of Agrenocythere
pliocenica is generally spineless (or very subdued
spines) and without prominent pore conuli as in A.
spinosa, new species, or many of the variants of A.
hazelae. Dimorphism is very strong (Plate 3: figures
3, 4; Plate 5; figures 3, 4; Figures 44-50) due to the
enlargement of the posteroventer in the male, a characteristic
not unlike that in Cletocythereis rastromarginata
(Brady). This feature was not noted to be as
strong in other species of Agrenocythere, but dimorphism
in these other species is quite apparent.
The castral arx of A. pliocenica as described in the diagnosis
is confined primarily to the central castrum. It
is similar to the other H-like constructions of the more
conservative forms of A. hazelae and A. americana,
new species. Its similarity with these species strongly
suggests phylogenetic ties with the stock of these forms
rather than those of more radiate {A. radula) or
promontory types {A. antiquata, new species). The
ventrolateral carina is fused and blade-like with few
fenestra noted (the muri may be strongly excavate,
however). The dorsal bullar series are simple dorsal
projections of the reticulum, less pronounced than A.
hazelae; however, they may be attenuated into bladelike
protuberances.
DIMENSIONS.—Length of hypotype male 1.49 mm,
height 0.61 mm; length of hypotype female 1.40 mm,
height 0.73 mm.
DISTRIBUTION.—Neogene (Pliocene and early Pleistocene)
of Italy from near Bologna (San Ruffilo) in
northern Italy to Sicily (Trubi formation) and Calabria
(La Castella section, Pliocene and late Pleistocene)
; also in DSDP XIII 132 in the Tyrrhenian
Sea floor.
Agrenocythere gosnoldia, new species
FIGURES 51-53
FIGURE 44.—Agrenocythere pliocenica (Seguenza, 1880) ;
adult, male (USNM 174697) : (A) exterior of left valve with
the order of the fossae in the ballium and the locations of
pore conuli indicated; (B) the interior of the right valve
showing the narrow and delicate holamphidont hinge elements;
(c) the right and left valves as seen in dorsal view.
Specimen 1625 microns in length.
ETYMOLOGY.—Named for the R/V Gosnold of the
Woods Hole Oceanographic Institute, which collected
the material in which the specimen was found.
HOLOTYPE.—Left valve, adult male (?); Figures
52, 53; USNM 168375A; paratype USNM 174365B.
TYPE-LOCALITY.—Middle Eocene outcrop in Block
Submarine Cayon at lat. 39°49'N and 7l°12'W at a
NUMBER 12 79
FIGURE 45.—Stereophotomicrographs of a hypotype (USNM 174350), an adult, female left
valve of Agrenocythere pliocenica (Seguenza, 1880), from the Pliocene of San Ruffilo, Italy
(ARL 4513) as seen from left lateral, and left anteroventral oblique views (x 55).
80 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
FIGURE 46.—Stereophotomicrographs of the castrum of a female hypotype (same specimen as
Figure 45) of Agrenocythere pliocenica (Seguenza, 1880) (xl60).
FIGURE 47.—Stereophotomicrographs of the castrum of a male hypotype (same specimen as
Figure 48) of Agrenocythere pliocenica (Seguenza, 1880) (xl60).
NUMBER 12 81
FIGURE 48.—Stereophotomicrographs of a hypotype (USNM 174349), an adult, male left valve
of Agrenocythere pliocenica (Seguenza, 1880), from the Pliocene of San Ruffilo, Italy (ARL
4513) as seen from left lateral, and left anteroventral oblique views (x50).
FIGURE 49.—Stereophotomicrographs of a hypotype (USNM 169376), an adult, female left valve of Agrenocythere pliocenica
(Seguenza, 1880), from the Pliocene Trubi formation of Sicily near Licata (ARL 4468), seen from left lateral, and left anteroventral
oblique views (x60).
NUMBER 12 83
FIGURE 50.—Stereophotomicrographs of the castrum of a female hypotype (same specimen as in
Figure 49) of Agrenocythere pliocenica (Seguenza, 1880). (xl80)
depth of 1070 meters; yellow calcareous clay. Hazel
sample 2621C (Gibson, Hazel, and Mellow 1968).
DIAGNOSIS.—This species can be distinguished from
others of the genus by its high anterior, its massive
muri, especially periferal to the margin as they form
the blade-like bullar series, wide anterior and posterior
marginal rims. Wide muri also join to support the
ventrolateral ridge and arcis region. The castrum is
massive yet simple with its many parts being subsumed
under its generally bold architecture. Pore conulus
Leo remains distinct as do many of the others,
especially Charon. The ocular ridge is wide but not
prominent as a tubercule.
COMPARISONS.—Although the basic patterns of the
reticulum and the principal character complexes are
those of Agrenocythere, new genus, the muri of the
reticulum are exaggerated into wide blade-like or
flange-like features in the castral region and especially
around the periferal margins. Within the reticular
fields the muri are not strongly excavate nor celate.
There are many small conjunctive spines, in addition
to the well-developed but short pore conuli. The posterior
caudal extension is well formed and very trachyleberid.
The ocular ridge is probably the widest of
the Agrenocythere species. The castral arx is similar
both to A. antiquata, new species (which also has a
specular promontory) and A. hazelae (whose arx extends
over the ballial rampart in the anterodorsal
sector) in that it is massive in relief (becoming highest
between the specula and the anterodorsal ballial
rampart) and tends to extend beyond the central castral
region toward the posterodorsum. An inflation of
the rampart near conulus Leo is also suggestive of the
development of a local parapectus.
The ventrolateral carina is strongly excavate and
flange-like. I have noted a large blunt perforate tubercule
on the posteroventer between the terminal
spine of the ventrolateral carina and the inner ventral
margin. Such a large feature has also been noted in
Oertliella aculeata and smaller homologous developments
in other species as well. Its function is not
guessed here, but its presence is conspicuous.
DIMENSIONS.—Length of holotype 1.14 mm;
height 0.62 mm.
DISTRIBUTION.—One locality (Block Canyon) but
many specimens from the middle Eocene of the canyons
along the Atlantic shelf of North America.
84 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
FIGURE 51.—Agrenocythere gosnoldia, new species, adult
male ( ? ) : (A) exterior of the left valve (USNM 168375A)
with the order of the fossae in the ballium and the locations
of the pore conuli indicated; (B) the interior of a broken
right valve (USNM 174365B) showing the muscle-scar pattern;
(c) the hinge elements of the left valve; (D, E) the
right and left valves as seen from dorsal views. Scale =: 100
microns.
Agrenocythere antiquata, new species
FIGURES 54-58; PLATE 4: FIGURES 5, 6; PLATE 6: FIGURES
5, 6
Bradleya hazelae (van den Bold).—Ascoli 1969:54.
Trachyleberis? hazelae (van den Bold).—van den Bold 1960:
165.
ETYMOLOGY.—Antiquata, Latin; the old one.
TYPE-SPECIMEN.—Holotype, whole adult specimen;
Figure 55, USNM 174343.
TYPE-LOCALITY.—Trinidad; lower Eocene, Hospital
Hill formation, van den Bold locality RHC 1054.
AGE.—Paleogene of Caribbean and Italy.
DIAGNOSIS.—Distingiushed from other species of
Agrenocythere, new genus, by its slightly smaller to
moderate size (1.17 mm length), exaggerated and
massive dorsal bullar series, central castrum, and
prominent pore conuli Leo and Charon (which is
developed into an elongate promontory). The anterior
marginal rim is narrow; the posterior is caudate,
flattened, and extended; the ventrolateral ridge is
narrow and high. There are few spines and the muri
are well formed but not prominent, often obscured by
infilling of fine marly matrix. The specula is very
prominent forming a Matterhorn-like projection with
a long slope extending toward the murus between
numbers nine and ten ballial fossae. The arx is best
developed in the central region; however, in some
middle to late Eocene specimens the arx may extend
to the outer rampart in the anterodorsal sector. The
rampart is poorly formed in the posterior sectors and
there is no parapectus. The eye tubercule is poorly
formed and the species is considered blind; however,
there is a conspicuous short ocular ridge extending
ventrally.
COMPARISONS.—This species is only slightly smaller
among the Caribbean forms, but in Italy it is notably
smaller than Agrenocythere pliocenica. Its castrum is
most like that of the middle Eocene species A. gosnoldia,
new species, but has its central part (including
the specular region) much more accentuated and its
arx sharper over the ballial region. The specimens are
not usually well preserved. The arx is massive and the
two muri that extend dorsally forming the H configuration,
mentioned in other species descriptions around
the fossa arcis and pervial fossa, is poorly developed
to well formed. The distal components of the H are
usually subdued compared to the high ridge that is
comparable to the cross-bar of the H. Examination of
NUMBER 12 85
FIGURE 52.—Stereophotomicrographs of the holotype (USNM 168375) of an adult male (?),
left valve of Agrenocythere gosnoldia, new species, from the middle Eocene of the continental
slope of northeastern North America (H2621C), as seen from left lateral, and left anteroventral
oblique views (x50).
86 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
FIGURE 53.—Stereophotomicrographs of the castrum of the holotype of Agrenocythere gosnoldia,
new species (xl60).
van den Bold's Hospital Hill specimens (upper middle
Eocene of Trinidad, RHC 1042 and Renz 75) shows
an arx with the ballial segment well formed as in A.
hazelae, yet smooth, narrow, and nonexcavate. The
short ridge found in the posteromedian region (near
pore conuli Charon) is prominent, unlike A. hazelae.
The dorsal bullar series is also pronounced. The
similarity between the Italian specimens, first identified
from the "scaglia rossa" of the Possagno section
(lower Eocene; possibly upper Paleocene, Figure 54)
by Ascoli (1969) is remarkable. From my examinations
of the specimens of this region and those of
Trinidad (Figure 56), I would agree with van den
Bold (quoted in Ascoli's report) that they are the
same form, but I would disagree that they are A.
hazelae and I am making them a separate species. As
discussed elsewhere, I believe that this species is obviously
the best candidate for the ancestral form of A.
hazelae and other Atlantic Agrenocythere species. I
have included illustrations of an Eocene specimen
from Cuba (Figure 55) and one from the Oligocene
or Rockall Plateau in the northeastern Atlantic,
which seems transitional in form between A. antiquata
and A. hazelae.
DIMENSIONS.—Length of holotype 1.17 mm;
height 0.69 mm.
DISTRIBUTION.—Caribbean and Atlantic Paleogene
(see Table 3) and Mediterranean lower Eocene.
Agrenocythere? cadoti, new species
FIGURES 59, 60
HOLOTYPE.—Left valve, adult male; Figures 59, 60;
University and Kansas collections, KU mip 1007900.
TYPE-LOCALITY.—Southern Ocean, south of Australia
; Tasman Plateau vicinity of RV Eltanin station
32, Cruise 39, Grab 10; lat. 48°26.4'S and long.
148°17.2'E; 960 meters depth; bottom temperature
unknown. Twenty specimens examined. Ten paratypes
have been reposited in the University of Kansas
collections.
AGE.—Recent; no living specimens found.
DIAGNOSIS.—Carapace elongate, rectangular with
evenly rounded ends; reticulum with massive nodose
muri; dorsal bullar series absent or very suppressed;
NUMBER 12 87
pression of feature complexes is not typical of Agrenocythere,
yet it is not typical of related genera either. It
is possible that this is an extreme derivative of A.
radula, but this is conjecture. There are general similarities
in the muslce-scar pattern with some species of
Cletocythereis (broken V-shape). There are also similarities
to specimens others have identified as A. semivera
Hornibrook. Perhaps the publication of this
species will bring these problems more to fore. It may
be even more closely related to A. semivera. The
specimens I have available of this species are not
conclusive (their identity with the illustration of Hornibrook
is in doubt).
FIGURE 54.—Agrenocythere antiquata, new species, adult,
female (?), from the Eocene of the Possagno section of
northern Italy as seen from lateral (A) and dorsal (B) views
(length of specimen 1100 microns, USNM 174685).
the castrum is evenly though irregularly murose with
indistinct subdivisions, no arx; no eye tubercule; the
antennal muscle scar may be divided although the
V-shape is at least residually present.
DISCUSSION.—This species, which is just now becoming
known, may very well not belong to Agrenocythere,
new genus. The similarity of the reticular
pattern with species of Agrenocythere is striking, but
as other genera also have this pattern this congruence
may be misleading. The overall shape and even ex-
FIGURE 55.—Agrenocythere antiquata, new species, adult
male, right valve (USNM 174361), from the upper Eocene
of Habafia Province, Cuba (Cantera Kohly, Bosquet de Habafia,
Bank of Rio Almendares) as seen in (A) lateral, (B)
interior, and (c) dorsal views (length of specimen 1230 microns)
.
SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
FIGURE 56.—Stereophotomicrographs of a holotype (USNM 174343) of an adult specimen of
Agrenocythere antiquata, new species, from the Eocene of Trinidad (RHC 1054), as seen from
the left lateral, and left anteroventral oblique views (x50).
NUMBER 12 89
FIGURE 57.—Stereophotomicrographs of an adult, female left valve (USNM 174346) of Agrenocythere
species from the Oligocene of the North Atlantic (Rockall Plateau, DSDP 117A, core 2,
section 6) as seen from the left lateral, and left anteroventral oblique views (x50). This form
appears to be transitional between A. antiquata, new species, and A. hazelae.
DIMENSIONS.—Length of holotype 0.99 mm,
height 0.52 mm.
DISTRIBUTION.—Known only from one sample (the
type-locality described above) south of Australia in
960 meters of water near the extreme southeastern
limits of the known geographic range of Agrenocythere
(in conjunction with the possible member species
A. semivera Hornibrook).
Genus Oertliella Pokorny, 1964
Oertliella Pokorny, 1964:283.
TYPE-SPECIES.—Cythere reticulata Kafka, 1886,
from the Turonian of Bohemia, Czechoslovakia.
90 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
FIGURE 58.—Stereophotomicrographs of the castrum of an
Oligocene specimen (same specimen as shown in Figure 57)
of Agrenocythere species (xlOO).
EMENDED DIAGNOSIS.—Summarized and corrected
from Pokorny (1964a). Carapace surface strongly reticulate
with the reticulum bearing no castral structures
(such as an arx or parapectus) except the pore
conuli typical of the several related reticulate trachyleberid
genera. Anterior marginal ridge narrow without
ocular ridge. Dorsal ridge (carina) originating
through the strengthening of several muri of the reticulum,
low, reduced to spines (not protuberances
such as a bullar series), or with an elongate crest
formed by the fusion of the spines or extension of the
carinae. Likewise the ventrolateral ridge (carina)
may be weak or strong and it may be wide, and
crest-like in certain species whose marginal carinae
are well developed. Median ridge absent and the posterior
reticular field is unadorned except with five or
six pore conuli. The same is true of the anterior reticular
field. With marginal rim around the ventral
commissure. An eye tubercule is present.
Hinge hemi-holamphidont. Frontal muscle scar Vshaped,
adductors undivided. Duplicature narrow to
median in width. Radial pore canals numerous. Sexual
dimorphism may be strong with the posteroventer
of the male extended.
AGE.—Upper Cretaceous and Paleogene of Europe.
REMARKS.—Emended to include a greater range of
species development than considered by Pokorny, and
to be set in terms comparable to those used to describe
Agrenocythere, new genus, and other related genera.
The original description by Pokorny (1964) was very
abbreviated. He credits Oertli (1963)—which statement
I cannot find—with recognition of the independent
status of the genus. Pokorny's paper included two
illustrations of O. reticulata (Kafka) whose silhouettes
are given in this report (Plate 3: figures 5, 6; Plate 5:
figures 5, 6). It is noted that in the specimen considered
the male (Pokorny 1964a, pi. 1: fig. 3) a long
dorsal ridge is present (as compared to the supposedly
more spinose female). More highly calcified species of
this same generic form (especially those with celate
muri) would not necessarily have such a sparse ornament
as exhibited by O. reticulata. An example is the
new species described here, O. ducassae, which is characterized
by flange-like carinae, but in most other respects
is like the type-species. Another extreme variation
is O. aculeata (Bosquet) shown in Figures 61 and
62, which is very tuberculate due to enlargement of
the pore conuli. O. horridula (Bosquet), the Maestrichtian
predecessor of O. aculeata is similarly enlarged in
this manner. Some latitude in the description of the
genus must be allowed.
Another important addition to the diagnosis is the
presence of eye tubercules. There is some room for
doubt about the appropriateness of this character as
being generically important, because any species could
conceivably become blind as it invades deeper water.
It also might become heavier and more massive as its
species invade the surf zone. Agrenocythere, however,
of which several species are described in the present
report, is believed to have evolved from Oertliella or
an Oertliella-like form. Agrenocythere is blind (assuming
that it in turn evolved as a deep-sea genus)
and began to develop several new characteristics (a
castral complex, for example), as well as loss of the
eye tubercule. Whereas some species of Oertliella may
have become blind, it is not typical of this shallow
marine genus.
Pokorny (1964a) made comparisons of Oertliella
with Hermanites Puri, which has been a very confused
genus. At that time the muscle scars of Hermania
reticulata Puri, the type-species of Hermanites,
were not known. The frontal scar is divided, with a
U-shaped scar below and a single simple scar overlyFIGURE
59. Stereophotomicrographs of the holotype, a male (?) of Agrenocythere? cadoti, new
species, from the Recent of the Tasman Plateau (ELT 39-32(10); lat. 48°26.4'S; long.
148°17.2'E- 960 meters; KUIMP 1007900; x80), as seen from the left lateral and left anteroventral
oblique views.
92 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
FIGURE 60.—Stereophotomicrographs of the central part of the castrum of the holotype (Figure
59) of Agrenocythere? cadoti, new species (x200).
FIGURE 61.—Stereophotomicrographs of the castrum of the specimen in Figure 62, Oertliella
aculeata (Bosquet, 1852) (xl80).
NUMBER 12 93
FIGURE 62.—Stereophotomicrographs of a hypotype (USNM 174340), an adult female (?) left
valve, of Oertliella aculeata (Bosquet, 1852), from the upper Eocene (Calcare de Blaye) of
southwestern France (ASA, 1'Octroi Commune, Blaye) as seen from the left lateral and left anteroventral
views (x60).
94 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
FIGURE 63.—Stereomicrographs of the holotype (USNM 174386) of a right valve of Oertliella
ducassae, new species, from the Eocene (Bartonian) of the C6te de Basque section, Biarritz,
France (Cheetham 22 VIII 68, No. 7; x90).
NUMBER 12 95
ing one side of the U (similar to Hornibrookella). It
is not a V-shaped scar typical of many trachyleberids
or even as well developed as some divided V-shaped
scars of Cletocythereis species. I do not consider it
possible to establish a close comparison between Oertliella
and Hermanites, sensu stricto, unless one allows
for considerable adaptive change in both the reticulum
and the frontal muscle-scar pattern. At present
the consensus is that these two forms are of different
genera and probably represent different families.
Oertliella ducassae, new species
FIGURES 63-66
ETYMOLOGY.—Named in honor of Mile. Odette
Ducasse, whose ostracode work in southwestern
France is becoming well known.
TYPE-SPECIMEN.—Holotype an adult right valve
(USNM 174386) from the Eocene of southwestern
France on the Cote de Basque (Figures 63, 64).
TYPE-LOCALITY.—Section on the Cote de Basque to
the west of Biarritz, France, near the road and sea
wall, Cheetham locality 22 VIII 68, No. 7.
AGE.—Bartonian, Eocene.
DIAGNOSIS.—A celate species of Oertliella with
wide flared dorsal and ventrolateral carina (spines
present but integrated into the carina) and fossae
partly closed by spines directed inward from the outermost
flanged portions of the muri (extensions of the
tegmen). Pore conuli present but comparatively subdued.
COMPARISONS.—Celate muri and wide crest-like
carina distinguish this species from either the typespecies
or O. aculeata, which is tuberculate (with
extensions of the pore conuli) by comparison. A slight
variation in form in this species is seen in specimens
collected from the Paleocene of Rockall Plateau
(DSDP XII 117A, Core 7, Section 1). This form
abundantly in these samples (Figures 65, 66). The
dorsal carina is not so crest-like, but the celation is
present and the posterior is acuminate.
DIMENSIONS.—Length of holotype 1.0 mm, height
0.5 mm. Specimens from Rockall Plateau slightly larger
(1.11 mm x 0.57 mm).
DISTRIBUTION.—Upper bathyal to outer shelf of
western Europe and the northeastern Atlantic during
the Paleogene.
FIGURE 64.—The castral region of the holotype of Oertliella ducassae, new species (same specimen
as in Figure 63; x200).
96 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
FIGURE 65.—Stereophotomicrographs of an adult female whole specimen (paratype, USNM
174338) of Oertliella ducassae, new species, showing eye tubercules and celate muri, from the
Paleocene of Rockall Plateau (DSDP XII, Hole 117, core 8, section 1) as seen from lateral
and anteroventral oblique views (x75).
97
FIGURE 66.—Stereophotomicrographs of the castrum of a specimen (same as in Figure 65) of
Oertliella ducassae, new species (x200).
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1966. Cytheracea (Ostracodes du Maestrichtien de Maestricht
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Gibson, T. G., J. E. Hazel, and J. F. Mello
1968. Fossiferous Rocks from Submarine Canyons off the
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Guppy, J. L.
1921. Microzoa of the Tertiary and other Rocks of Trinidad
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Hanai, Tetsuro
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Harding, J. P., and P. C. Sylvester-Bradley
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1964. Zur Kenntnis der Ostracoden des Roten Meeres.
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Hazel, J. E.
1967. Classification and Distribution of the Recent Hemicytheridae
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1952. Tertiary and Recent Marine Ostracoda of New
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Ishizaki, K.
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Jones, T. R.
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1948. Contributions to the Knowledge of the Young-Caenozoic
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1939. Some Small Foraminifera, Ostracoda and Otoliths
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1963. Faunes d'Ostracodes du Mesozoique de France. 57
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1954. Contributions to the Study of the Miocene of the
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100 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
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Appendix: Distribution Data
Within the Appendix are included primary reference data regarding the distribution
of the material studied for the description of the taxa in the text. Figure 67 is a
bivariant plot of the length/height ratios of the Agrenocythere species showing the
differences in size among the adult or late instars examined. This is followed by
Tables 1-4 with locality information referred to previously in the text and maps
(Figures 1, 2, 3, and 30) unless included in their captions.
* * *
O
All measu rements x 100 in p)
T
1 3
L e n g th
FIGURE 67.—Variation in maximum size among the different species of Agrenocythere, new
genus. A bivariant plot of length-height ratios of eight species. The lower ends of the ranges
(indicated by lines) are subject to considerable error for the respective instars, because of sample
inadequacies; however, the upper ends of the observed ranges (the adult stages) are considered
to be more faithful to the real size differences.
101
102
Map
Designation *
SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
TABLE 1.—Distribution of Bradleya species, new genus
Station
Number
Depth
(meters) Latitude
Location
Longitude
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
ELT. 21-21
CHAL. 302
ELT. 21-10
CHAL. 300
DWBG99
DWHG 74
DWBG 121
DWHG 79
CHAL. 280
ALB. 4723
ALB. 4728
SWP 766C
SWP 770C
ALB. 2808
ALB. 2817
V20-27
ALB. 3375
ALB. 3376
ALB. 3363
VI9-19
VI9-20
VI9-21
VI2-122
A179-4
ALB. 2751
V3-72
V3-74
ALB. 2379
ALB. 2381
ALB. 2382
ALB. 2383
ALB. 2385
ALB. 2392
V3-41
ALB. 2659
ALB. 2679
All118A
All 119
TR. 13
CHAL. 78
V9-29
AH 156
All 159
All169A
ALB. 2763
RC8-91
VI2-54
RC8-41
VI6-66
VI9-222
IIOE 380A
IIOE 380C
2610
3137
2475
3220
3030
3320
3440
3492
3475
1930
1860
960
1144
496
4076
2197
1132
1789
3760
3539
3168
2756
2965
1257
3746
3733
2683
2433
2295
2160
1335
1324
832
931
1430
1135-1153
2095-2223
1955
1800
4675
Lower Miocene
3459
834-939
587
1227
2723
4082
2897
2995
2005
Cretaceous-Miocene
935
950
53°01'S
42°43'S
36°41'S
33°42'S
20°33'S
28°29'S
27°09'S
23°35.5'S
18°40'S
10°14'S
13°47.5'S
4°21'S
3°16'S
0°36.5'S
0°48'S
6°28'N
2°34'N
3°9'N
5°43'N
13°14'N
12°31'N
10°36'N
17°2'N
16°36'N
16°54'N
23°26.5'N
22°49'N
28°15'N
28°05'N
28°19'45"N
28°32'N
28°51'N
28°47.5'N
29°12.5'N
28°32'N
32°40'N
32°19'N
32°16'N
49°38'N
37°26'N
3°47.5'N
0°46'S
7°58'S
8°2'S
24°17'S
33°25'S
41°14.4'S
43°38'S
42°39'S
33°22'S
32°58'S
32°58'S
75°43'W
82°11'W
93°37'W
78°18'W
81°51'W
106°30'W
109°50'W
118°13.5'W
149°52'W
107°45'W
114°22'W
81°27.8'W
81°9.3'W
89°19'W
89°8.9'W
111°45'W
82°29'W
82°8'W
85°50'W
78°22'W
78°18'W
79°21'W
74°23.9'W
74°48'W
63°12'W
94°3.5'W
92°21 'W
87°42'W
87°56'W
88°1.5'W
88°06'W
88°18'W
87°27'W
87°02'W
78°42'W
76°40.3'W
64°34'W
64°32'W
13°28'W
25°13'W
34°37'W
29°26'W
34°22'W
34°24'W
42°48.5'W
41°54'W
6°7'W
51°16'E
45°40'E
34°24'E
43°37'E
43°41'E
NUMBER 1 2 103
TABLE 1.—Distribution of Bradleya species, new genus—Continued
Map
Designation *
Station
Number
Depth
(meters)
Location
Latitude Longitude
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
'See Figure 1.
IIOE 360B
IIOE 374C
IIOE 397D
IIOE 361G
IIOE 369D
IIOE 369G
IIOE 369J
IIOE 370B
IIOE 399
IIOE 400B
IIOE 363B
IIOE 363G
IIOE 363J
IIOE 363K
IIOE 367C
IIOE 367G
IIOE 407D
IIOE 409A
IIOE 413A
IIOE 418B
IIOE 418F
MSN-20D
RC9-148
RC9-150
NZOI B303
O-170L
NZOI A293
ALEX BANK 2
CAP 6 HG
RC11-158
RC10-164
RC10-163
ELT. 47-5056
ELT. 47-5057
ELT. 47-5064
ELT. 47-5061
ELT. 47-5068
ELT. 47-5072
DSDP II 11
0,4)
DSDP III 16
(2,6)
DSDP III 15
(7, 3; 8, 3)
OZAWA F
25510
ALB. 3708
ALB. 5301
ALB. 5218
Briggs 1
DSDP III 21
(4,4)
1360
1335
665
2750
1720
1140
910
925
1530
1530
2980
1350
1280
1190
3250
3140
1360
?
3530
3050
1550
1390
2056
2703
2888
2781
2689
2560
3363
3177
3766
3550
613
613
1728
1408
2308
3584
3571
Plio-Pleistocene
3527
U. Pliocene
3927
L. Miocene
Outcrop
U. Pliocene
130
400
38
75
2102
U. Cretaceous
27°39'S
27°09'S
26°14'S
25°50'S
24°04'S
24°12'S
24°25'S
22°33'S
21°12'S
21°12'S
23°45'S
23°38'S
23°36'S
23°43'S
22°37'S
22°42'S
17°32'S
16°12'S
12°32'S
8°5'S
4°14'S
9°23'S
29°41.3'S
31°17'S
45°7.8'S
30°43.2'S
28°59.3'S
11°5'S
4°15.5'S
20°55'N
31°43.5'N
32°43'N
50°13.67'S
49°43.53'S
51°09.54'S
51°05.48'S
51°08.88'S
51°33.40'S
29°56.58'N
33°23'E
34°09'E
34°04'E
37°21'E
36°16'E
36°01'E
35°47'E
36°10'E
36°24'E
36°24'E
43°10'E
43°24'E
43°24'E
43°25'E
41°22'E
39°19'E
43°05'E
43°41'E
45°50'E
41°37'E
40°59'E
109°16'E
113°42.4'E
114°33.1'E
177°55'E
156°24.39'E
172°28'E
175°10'E
171°55.5'E
149°54.5'E
157°30'E
157°30'E
74°36.27'E
71°02.16'E
75°46.27'E
76°35.34'E
76°03.82'E
78°56.19'E
44°44.80'W
30°20.15'S 15°42.79'W
30°53.38'S 17°58.99'W
Kaga Prov. Japan
Off Ose Zaki, Honshu, Japan
20°37'N 115°43'E
13°ll'15ffN 123o02'45ffE
OffN. Cape, N. Z.
28°35.10'N 30°35.85'W
104 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
TABLE 2.—Distribution of Poseidonamicus species, new genus
Map
Designation *
Station
Number
Depth
(meters) Latitude
Location
Longitude
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
DWBG 68
DWBG 70
DWBG 71
DWHG 48
DWBG 77
DWBG 76
DWBG 73
DWBG 74
DWBG 75
ELT. 21-10
CHAL. 300
DWBG 120
DWBG 121
DWHG 74
ALB. 4693
CAP 41 HG
DWBG 137
SDSE 58
ALB. 4611
V7-16
Al 67-43
A156-1
AH 120
A180-9
A180-15
R5-34
KMI-36
SP8-12
VI7-165
V22-230
V10-90
VI6-205
V9-29
VI6-200
ALB. 2763
V9-11
All 155
All 156
Al80-76
Al 80-73
V12-81
VI9-297
V9-19
VI6-39
RC8-91
VI2-53
VI2-60
V12-54
VI6-66
VI9-222
2820
2580
2790
4240
3820
3840
3080
3220
3650
3137
2475
3060
3320
3030
2089
3394
2770
4440
3292
2635
2605
1005
5018-5023
4060
4610
3750
4300
3252
3924
5048
4030
4045
4675
Lower Miocene
4095
1227
4120
3730-3783
3459
3510
3750
3671
4120
3730
4510
2723
3797
3115
4082
2995
2005
Cretaceous-Miocene
48°27'S
48°28'S
46°35.5'S
42°00'S
44°09'S
43°45'S
43°48'S
43°43'S
43°33'S
36°41'S
33°42'S
27°56'S
27°9'S
28°29'S
26°30'S
15°55.5'S
9°53'S
6°44'N
10°32'N
25°20'N
25°27'N
28°35.5'N
34°42'N
39°37'N
39°16'N
42°23'N
30°28'N
32°37.4'N
32°45'N
32°39'N
23°02'N
15°24'N
3°47.5'N
1°58'N
24°17'S
3°13.4'S
0°3'S
0°46'S
0°46'S
0°10'N
0°18.6'N
2°37'N
11°23'S
24°43'S
33°25'S
40°53.4'S
30°20.2'S
14°14.4'S
42°39'S
33°22'S
114°18'W
113°17'W
113°34'W
102°00'W
101°34.5'W
104°28'W
108°9'W
107°36'W
108°18'W
93°37'W
78°18'W
106°55'W
109°50'W
106°30'W
105°45'W
117°13.8'W
110°41'W
129°28'W
88°25'W
77°36'W
77°03'W
77°10'W
66°34'W
45°57'W
36°42'W
21°58'W
28°38'W
36°46'W
41°54'W
52°11.8'W
47°03'W
43°24'W
34°37'W
37°04'W
42°48.5'W
32°12.9'W
27°48'W
32°38.5'W
26°02'W
23°00'W
18°25.8'W
12°00'W
14°15'W
4°45'W
41°54'W
20°22.9'S
14°10.4'E
6°7'W
45°40'E
34°24'E
NUMBER 12 105
TABLE 2.—Distribution of Poseidonamicus species, new genus—Continued
Map
Designation *
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
Station
Number
IIOE 360B
IIOE 361B
IIOE 361G
IIOE 369D
IIOE 369G
IIOE 374C
IIOE 363B
IIOE 363E
IIOE 363K
IIOE 366A
IIOE 366C
IIOE 362D
IIOE 367C
IIOE 367D
IIOE 367G
IIOE 368C
IIOE 369A
IIOE 409A
IIOE 410A
IIOE 416A
DODO 117P
0-121G
RC9-147
RC9-148
RC9-150
RC9-143
VI8-222
O-170L
NZOI D593
NZOI A293
CAP 8 BG
ALEX BANK 1
RC10-161
RC10-163
RC10-164
ELT 47-5062
ELT 47-5064
ELT 47-5068
ELT 47-5072
ELT 47-5110
DSDP II 11
(1,1)
(1,4)
DSDP II 12c
0,3)
(4,2)
DSDP III 14
(2,3)
(8,3)
DSDP III 15
(1,3)
(2,1)
(2,5)
(3,5)
(7, 3; 8, 3)
Depth
(meters) Latitude
Location
Longitude
1360
1829
2750
1720
1205
1335
2980
1860
1190
2300
2710
3950
3250
2200
3140
2995
2270
?
3100
3850
3398
3994
2479
2056
2703
4396
1904
2781
3020-3100
2689
2560
2560
3587
3550
3766
1400
1728
2308
3584
2900
3571
Quaternary
Plio-Pleistocene
4457
Quaternary
? Pliocene
4343
U. Oligocene
L. Oligocene
3927
Pleistocene
L. Pleistocene
U. Pliocene
L. Pliocene
L. Miocene
27°39'S
26°34'S
25°50'S
24°04'S
24°12'S
27°9'S
23°45'S
23°40'S
23°43'S
23°9'S
23°9'S
24°18'S
22°37'S
22°15'S
22°42'S
23°0'S
23°48'S
16°12'S
15°7'S
8°45'S
18°21'S
5°39.1'N
29°19.6'S
29°41.3'S
31°17'S
41°21.8'S
38°9'S
30°43.2'S
41°00'S
28°59.3'S
13°39'S
11°5'S
35°5'N
32°43'N
31°43.5'N
51°05.48'S
51°09.54'S
51°08.88'S
51°33.40'S
53°21.27'S
29°56.58'N
19°41.73'N
28°19.89'S
30°53.38'S
33°23'E
35°59'E
37°21'E
36°16'E
36°02'E
34°9'E
43°10'E
43°21'E
43°25'E
43°9'E
43°7'E
41°26'E
41°22'E
40°21'E
39°19'E
38°31'E
37°47'E
43°41'E
44°21'E
43°39'E
62°4'E
82°13.4'E
113°22.2'E
113°42.4'E
114°33.1'E
114°08'E
140°37'E
156°24.39'E
178°25'E
172°28'E
174°58'E
175°10'E
158°0'E
157°30'E
157°30'E
76°35.34'E
75°46.27'E
76°03.82'E
78°56.19'E
70°58.47'E
44°44.80'W
26°00.03'W
20°56.46'W
17°58.99'W
106 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
TABLE 2.—Distribution of Poseidonamicus species, new genus—Continued
Map
Designation'
Station
Number
Depth Location
(meters) Latitude Longitude
63
64
DSDP III 16
(1,2)
(2,2)
(2, 6; 3, 3)
(4,3)
(5,3; 7, 3; 10, 3; 11, 3)
DSDP III 17
0 , 2 )
(2,3)
(3,2)
DSDP III 21A
(1,5)
?(3, 4)
3527
Pleistocene
L. Pleistocene
U. Pliocene
L. Pliocene
U. Miocene
4265
Pleistocene
L. Pliocene
L. Miocene
2113
L. Pliocene
U. Paleocene
30°20.15'S 15°42.79'W
28°02.74'S
28°35.10'S
06°36.15'W
30°35.85'W
•See Figure 2.
NUMBER 12 107
TABLE 3.—Distribution of Agrenocythere species, new genus
Map
Designation
"
1
2
3
4
5
6
7
8
9
10
11
12
13
13a
14
15
16
Station
Number
ALB 3376
ALB 3375
ALB 2383
ALB 2352
ALB 2140
ALB 2751
ALB 2754
GF 7871
K R 18192
D M 154
EL 1145b
R M 15715
Bo 202
Br 229
CH 4148
R H C 1042
R H C 1047
R H C 1049
R H C 1054
R H C 1065
Renz 75
Ky 7
Location
Latitude
03°09'N
02°34'N
28°32'N
22°35'N
17°36'N
16°54'N
11°40'N
Rio Almendares
A 156-1
H 2 6 2 1C
Stet. 12-36
DSDP I I I 19
(4; 6)
DSDP I I I 22
(4; 4)
DSDP I I I 14
( l a ; 3)
DSDP I I I 16
(6; 3)
DSDP I I I 17a
( i ; 3 )
(H
Tr
Tr
Tr
Tr
Tr
Tr
Tr
Tr
Tr
Tr
Tr
Tr
Tr
Tr
Tr
C
aba
28°35.5'N
39°49'N
39°45'N
28°32'S
30°01'S
28°20'S
30°53'S
28°03'S
Longitude
82°08'W
82°29'W
88°06'W
84°23'W
76°46'W
63°12'W
58°33'W
nidad
nidad
nidad
nidad
nidad
nidad
nidad
inidad
in id ad
inidad
nidad
nidad
nidad
nidad
nidad
,uba
na Prov.)
77°10'W
71°21'W
70°58'W
23°40.6'W
35°15'W
20°57'W
17°59'W
06°36'W
Depth
(meters)
2080
2197
2160
833
1738
3250
1645
outcrop
outcrop
outcrop
outcrop
outcrop
outcrop
outcrop
outcrop
outcrop
outcrop
outcrop
outcrop
outcrop
outcrop
outcrop
outcrop
1005
1070
880
4677
2134
4343
3526
4277
Temp.
(C°)
2 .6
2 .4
4 .3
7 .2
4 .3
-
3 .3
-
-
-
-
-
-
-
---
-
-
-
-
-
-
-
-
-
-
-
—
—
Core Level
(cm)
Beam Trawl
Beam Trawl
Beam Trawl
Beam Trawl
Beam Trawl
Beam Trawl
Beam Trawl
Lengua fm.
Lengua fm.
Lengua fm.
Cipero fm.
Cipero fm.
Cipero fm.
Cipero fm.
Cipero fm.
Hospital Hill
Hospital Hill
Hospital Hill
Hospital Hill
Hospital Hill
Hospital Hill
Hospital Hill
van den Bold
location
200, 280
Barrel Dredge
Core
F r am Ooze
Globigerina
ampliapertura
zone
Endeavor Ooze
Blake Ooze
Albatross Ooze
Agrenocythere
Species
A. malpeloensis
A. malpeloensis
A. americana
A. hazelae
A. hazelae
A. hazelae
A. hazelae
A. hazelae
A. hazelae
A. hazelae
A. hazelae
A. hazelae
A. hazelae
A. hazelae
A. hazelae
A. antiquata
A. antiquata
A. anitquata
A. antiquata
A. antiquata
A. antiquata
A. antiquata
A. antiquata
?
A. gosnoldi
A. antiquata
A. hazelae
A. hazelae
A. hazelae
A. hazelae
A. hazelae
Specimens
1
3
48
1
11
46
2
1
1
1
1
1
1
1
1
1
1
1
3
1
2
11
9
1
1
2
1
1
Age
Recent
Recent
Recent
Recent
Recent
Recent
Recent
L. Miocene
L. Miocene
L. Miocene
M. Miocene
M. Miocene
Miocene
E. Miocene
E. Miocene
L. Eocene
L. Eocene
L. Eocene
L. Eocene
L. Eocene
L. Eocene
L. Eocene
L. Eocene
Pleistocene
M. Eocene
M. Eocene
Rupelian
Chattian
Aquitanian
Messinian
Pleistocene
108 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
TABLE 3.—Distribution of Agrenocythere species, new genus—Continued
Map
Designation
*
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Station
Number
DSDP I I I 17a
(4; 3)
DSDP X I I 117
(6)
DSDP X II
117a (7; 8)
C22 V I I I 68
(7)
Ascoli (1969)
Ascoli
(Ancona loc.)
ARL 4513
ARL 4468
ARL 4473
Ascoli (3)
DSDP X I II
132 (11)
DSDP X I II
132 (18)
Pokorny
Kostice Loc.
Pokorny
Kostice Loc.
Oertli Sample
A2A 1'Octroi
DODO 117P
VI9-222
MSN 20D
Chal 191A
Elt 39-10 (32)
Location
Latitude Longitude
28°03'S 06°36'W
57°19.5'S 15°23'W
57°19.5'S 15°23'W
Cote de Basque,
Biarritz, France
Possagno section,
Treviso Prov., Italy
Near Ancona Italy
Near San Ruffilo,
Bologna, Italy
North of Licata,
Sicily
Near Agrigento,
Sicily; Greek Temple
Loc.
Crotone, Calabria
Le Castella Section
40°15.70'N 11°26.47'E
40°15.70'N 11°26.47'E
Near Louny,
Czechoslovakia
Near Louny,
Czechoslovakia
Near Martiques
(Bouches du Rhone),
France
Commune Blaye,
France
18°21'S 62°04'E
33°22'S 34°24'E
09°23'S 109°16'E
05°26'S 133°19'E
48°26.4'S 148°17.2'E
Depth
(meters)
4277
1048
1048
outcrop
outcrop
outcrop
outcrop
outcrop
outcrop
outcrop
2813
2813
outcrop
outcrop
outcrop
outcrop
3398
-
1390
1061
960
Temp.
(C°)
—
-
-
-
-
—
—
-
-
-
~
-
---
4.9°C
Core Level
(cm)
F r am Ooze
—
-
-
-
—
Trubi fm.
Trubi fm.
Trubi fm.
Trubi fm.
Trubi fm.
—
-
Lima ovata
zone
Calcaire
de Blaye
108-110
505
-
Dredge
Dredge
Agrenocythere
Species
A. haxelae (?)
Oertliella
atlantica
Oertliella
atlantica * *
Oertliella
atlantica * *
A. antiquata
A. antiquata (?)
A. pliocenica
A. pliocenica
Cythereis
ornatissima
A. pliocenica
A. pliocenica
A. pliocenica
Oertliella
reticulata
Cythereis
kosticensis
Oertliella
horridula
"Oertliella"
aculeata
A. spinosa
A. radula
A. radula
A. radula
A. cadoti
Specimens
1
18
19
5
5
3
164
65
84
5
4
2
—
-
-
1
2
1
1
22
Age
Bormidian
Oligocene
Paleocene
Bartonian
E. Eocene
E. Miocene
Pliocene
Pliocene
Conacian
Late
Pliocene
Pliocene
Pliocene
Turonian
Turonian
Santonian
L. Eocene
Recent
Pliocene
Recent
Recent
Recent
*See Figure 3.
**Eye tubercules.
NUMBER 1 2 109
TABLE 4.—Distribution of Agrenocythere species in Mozambique Channel
Map
Designation
*
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Station
Number
IIOE 360B
IIOE 374D
IIOE 361B
IIOE 370B
IIOE 368C
IIOE 367D
IIOE 363B
IIOE 363D
IIOE 363G
IIOE 363G
IIOE 363J
IIOE 363J
IIOE 363K
IIOE 363K
IIOE 365B
IIOE 365D
IIOE 399A
IIOE 400A
IIOE 400A
IIOE 407D
IIOE 409A
IIOE 410A
IIOE 413A
IIOE 416A
IIOE 418A
Locat
Latitude
27°39'S
27°09'S
26°34'S
24°25'S
23°00'S
22°15'S
23°45'S
23°45'S
23°38'S
23°38'S
23°36'S
23°36'S
23°43'S
23°43'S
23°19'S
23°20'S
22°33'S
21°12'S
21°12'S
17°32'S
16°12'S
15°07'S
12°32'S
08°45'S
05°11'S
ton
Longitude
33°23'E
34°09'E
35°59'E
35°47'E
38°31'E
40°21'E
43°10'E
43°11'E
43°24'E
43°24'E
43°24'E
43°24'E
43°25'E
43°25'E
43°33'E
43°32'E
36°10'E
36°24'E
36°24'E
43°05'E
43°41'E
44°21'E
45°50'E
43°39'E
41°38'E
Depth
(meters)
1360
1335
1829
910
2995
2200
2980
1605
1350
1350
1280
1280
1190
1190
420
475-695
925
1530
1530
1360
400
3100
3530
3850
3050
Temp.
(C°)
-
2.5
5.6
1 .6
2.5
2.1
3.8
4.2
4.2
4.7
4.7
4.9
4.9
12.0
-
5.5
3.5
3.5
4.5
-
2.2
1.5
1 .3
—
Core Level
(cm)
Grab
Grab
Grab
Grab
Grab
Grab
Grab
Trawl
Grab
Grab
Trawl
Trawl
Trawl
Trawl
Grab
Trawl
Trawl
Trawl
Trawl
Trawl
Dredge
Trawl
Trawl
Trawl
Trawl
Agrenocythere
Species
A. spinosa
A. spinosa
A. radula
A. spinosa
A. radula
A. radula
A. radula
A. radula
A. radula
A. spinosa
A. spinosa
A. radula
A. radula
A. spinosa
A. spinosa
A. spinosa
A. spinosa
A. spinosa
A. radula
A. spinosa
A. radula
A. radula
A. spinosa
A. radula
A. radula
Specimens
11
28
2
1
1
1
5
24
3
10
16
1
1
9
1
18
4
119
6
142
37
17
5
2
4
Age
Recent
Recent
Recent
Recent
Recent
Recent
Recent
Recent
Recent
Recent
Recent
Recent
Recent
Recent
Recent
Recent
Recent
Recent
Recent
Recent
Recent
Recent
Recent
Recent
Recent
"See Figure 30.

PLATES
112 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
PLATE 1
1-4. Cletocythereis rastromarginata. (Brady), the lectoholotype (designated herein, British Museum
specimen BM 80.38.105). The left valve (of a whole specimen, separated for study) from
Brady's Challenger locality "off reefs at Honolulu, 40 fathoms." Photographs (vegetable coloring
stain) taken in incident and transmitted light showing (1) reticular pattern with castrum, (2)
exterior morphology of the carapace, (3) holamphidont hinge, and (4) V-shaped frontal scar
(with posterodorsal part slightly severed). Designated as the type-species of Cletocythereis by
Swain in 1963 (approximately x80 and x225).
5. Agrenocythere? semivera? (Hornibrook, 1952), a left valve, female (USNM 174678) from
the upper Eocene of South Island, New Zealand (Totara Limestone; locality of W. M. Briggs,
Jr., SI-25, N.2. Sheet Fossil No. S136/f 1199). The identification of this specimen is not certain.
Hornibrook's drawing (1952, pi. 8: fig. 103) is stylized (x55).
6. Limburgina quadrazea (Hornibrook, 1952), a left male valve (USNM 174679), from the
upper Paleocene Tioriori Limestone (Mangaorapan), Chattam Islands, New Zealand (New Zealand
Geol. Survey loc. F5080; Courtesy W. M. Briggs, Jr.). This species contains several of the
characteristics common to the ancestral group of several of the genera discussed in the text
(x70).
7. Bradleya species, left valve (USNM 174680) of a yet unnamed species of Bradleya from the
Recent of New Zealand (NZOI E258, lat. 34°39'S; long. 172°10'E, 380 meters depth; courtesy
W. M. Briggs, Jr.) showing strong box-work mural structure in the posterior, a diminished
bridge (see p. 35) and the remainder of a median ridge (x50).
8. Bradleya (Quasibradleya) species, left valve (USNM 174681) of a yet unnamed species from
the Recent of New Zealand (locality same as Bradleya species of Plate 1: figure 7). This Recent
form is very similar to and descendant from B. (Q.) dictyonites of Oligocene age. They differ
primarily in the reticular pattern of the posterior (x50).
9. Bradleya species, a whole female specimen (USNM 174682) from the upper Paleocene, Tioriori
Limestone, from Chattam Islands, New Zealand (locality same as for specimen in Plate 1:
figure 6) transitional in form between Bradleya and Limburgina (x70).
10. Hermanites reticulata (Puri, 1954) ; one of the two right valves reposited by Puri as paratypes
(USNM P3286) of the type-species of Hermanites. From the Miocene, Alum Bluff stage,
Chipola formation; Washington Co., Florida (x85).
11-12. Hermanites cf. H. fungosa Butler, 1963, (1) left and (2) ri^ht valves from the Oligocene
(USNM 174683-4), Chickasawhey formation, Taylor Mill Creek (Hazel locality), just below
the Chione Limestone. This species is the closest, well-preserved specimen available to the type
illustrated as Plate 1: figure 10 and is probably immediately antecedant (x85).
NUMBER 12 113
.
*• I
m
- s.
fe
>#
- *
# ~ ^ v % ft ^
•" * * « * £ < *
• ^
;.^^ikfis
114 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
PLATE 2
1. Jugosocythereis pannosa (Brady, 1869), left valve (USNM 174686) from the south shelf (Recent)
of Puerto Rico (sample PA-2) (x75).
2. Jugosocythereis vicksburgensis (Howe and Law, 1936), left valve (USNM 174687) from the
Byram Marl (Oligocene), a road cut east of Engineers Warf, Vicksburg, Mississippi (x70).
3. Thaerocythere crenulata (Sars, 1865), left valve (USNM 174688) from the Atlantic shelf
(Recent) off of Maine, United States (Hazel, 1970, Sample 90, lat. 42°41'N and long.
67°22'W; 203 meters depth) (x80). The type-species of the type-genus.
4. Bradleya species, left valve (USNM 174689) of an undescribed species from about 800 meters
off Brazil (ALB 2756; lat. 3°22'S and long. 37°49'W) (x70).
5. Cletocythereis haidingerii (Reuss, 1846), left valve (USNM 174690) from the "Amphistegina"
Marl (Tortonian-Miocene) of Nussdorf in the Vienna Basin (Reuss, 1846, locality, sample
courtesy of P. A. Sandberg) (x70).
6. Cletocythereis species, left valve (USNM 174693) from Wynyard Beach (Recent) of Northern
Tasmania, more massive and shorter than the type-species (x85).
7. Bradleya normani (Brady, 1865), left valve (USNM 174694) from near Kerguelen Island
(Recent; Eltanin station 47-5064, lat. 51°09.54'S and long. 75°46.54'E; depth 1728 meters),
just north and west of the station (Challenger 150) from which Brady (1880) identified this
species (x70).
8. Poseidonamicus major?, new species, left valve (USNM 174695) of a coarse variant of this
species (possibly female) of Miocene age (Messinian) from the South Atlantic (DSDP III 16,
core 8, section 3) (x65).
9. Bradleya? telisaensis (Le Roy, 1939), a paratype from the "Miocene" of Sumatra (Loc.
HO-1512; Tapoeng Kiri area near Aliatan, Telisa; USNM 56147b) (xlOO).
10. Bradleya (Quasibradleya) species, a left valve (USNM 174696) from the Philippine Islands
(Recent; ALB 5218, lat. 13°11'15"N and long. 123°02'45"E; depth 20 fathoms) (x70).
NUMBER 12 115
m .
-
«v
116 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
PLATE 3
(Page 118)
Reticular silhouettes of eight forms including Agrenocythere, new genus, and two other genera
with positions of pore conuli (dots) indicated. [All illustrations reduced approximately to common
size.] This series (and that of Plates 5 and 6) shows the degrees of similarity of major
features among the forms listed below and basic changes in allometry.
1. Argenocythere gosnoldia, new species, middle Eocene of eastern North America.
2. Cythereis ornatissima, Reuss, 1846, Coniacian of Sicily.
3-4. A. pliocenica (Seguenza, 1880), (3) female and (4) male, San Raffilo, Italy, Pliocene.
5-6. Oertliella reticulata (Kafka, 1886), (5) female and (6) male, Turonian, Bohemian, Czechoslovakia.
7. A. spinosa, new species, Recent, Mozambique Channel.
8. A. radula (Brady, 1880), Recent, Mozambique Channel.
PLATE 4
(Page 119)
Reticular silhouettes of eight variations of Agrenocythere, new genus, with positions of pore conuli
(dots) indicated. [All illustrations reduced approximately to common size.] This series (and
that of Plates 3 and 4) shows the degrees of similarity of major features among the forms listed
below and the basic changes in allometry. See page 4 for discussion of method.
1—4. Agrenocythere hazelae (van den Bold, 1946), (1) Recent of eastern Pacific (right valve,
reversed), (2) Miocene of South Atlantic, (3) Miocene of Trinidad, and (4) Recent of Caribbean.
5-6. Agrenocythere antiquata, new species, Eocene; (5) Possagno, Italy (male); and (6)
Eocene of Trinidad (female).
7. Agrenocythere americana, new species, Recent, Gulf of Mexico.
8. Agrenocythere pliocenica (Seguenza, 1880), Pliocene, Sicily.
NUMBER 1 2 117
PLATE 5
(Page 120)
Reticular silhouettes of eight forms of Agrenocythere, new genus, and two other genera with
positions of pore conuli (dots; Plate 3), fossal pattern and constellar framework (Plate 5) indicated.
[All illustrations reduced approximately to common size.] This series (and that of Plates
5 and 6) shows the degrees of similarity of major features among the forms listed below and
basic changes in allometry.
1. Agrenocythere gosnoldia, new species, middle Eocene of eastern North America.
2. Cythereis ornatissima, Reuss, 1846, Coniacian of Sicily.
3-4. A. pliocenica (Seguenza, 1880), (3) female and (4) male, San Raffilo, Italy, Pliocene.
5-6. Oertliella reticulata (Kafka, 1886), female and male, Turonian, Bohemian, Czechoslovakia.
7. A. spinosa, new species, Recent, Mozambique Channel.
8. A. radula (Brady, 1880), Recent, Mozambique Channel.
PLATE 6
(Page 121)
Reticular silhouettes of eight variations of Agrenocythere, new genus, with positions of pore conuli
(dots; Plate 4) fossal pattern and constellar framework (Plate 6) indicated. [All illustrations
reduced approximately to common size.] This series (and that of Plates 3 and 4) shows the
degrees of similarity of major features among the forms listed below and the basic changes in
allometry. See page 4 for discussion of method.
1-4. Agrenocythere hazelae (van den Bold, 1946), (1) Recent of eastern Pacific (right valve,
reversed), (2) Miocene of South Atlantic, (3) Miocene of Trinidad, and (4) Recent of Caribbean.
5—6. Agrenocythere antiquata, new species, Eocene; Possagno, Italy (male) ; and Eocene of Trinidad
(female).
7. Agrenocythere americana, new species, Recent, Gulf of Mexico.
8. Agrenocythere pliocenica (Seguenza, 1880), Pliocene, Sicily.
118 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
NUMBER 12 119
120 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
NUMBER 1 2 121
122 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
PLATE 7
1. Bradleya albatrossia, new species; left valve adult; note boldness of muri, yet no median ridge
or anterior bridge; Recent, China Sea off Hong Kong; Albatross station 5301, lat. 20°37'N,
long. 115°43'E, 208 fathoms; holotype USNM 174318 (x70).
2. Bradleya albatrossia, new species; right valve of the same species as Plate 7: figure 1, but with
slightly bolder muri and still no longitudinal ridges except for the ventrolateral carinae; Recent,
Sample Alex No. 2, Alexa-Penguin Bank, lat. 11°5'S, long. 175°10'E, North Fiji Basin, 2560
meters; paratype USNM 174319 (x70).
3. Bradleya japonica, new species; left valve adult with nude anterior marginal region, broad
ventrolateral carina, and irregular murate development; Recent, Albatross station 3708 off Honshu
Island, Japan, 60-70 fathoms; holotype USNM 174320 (x50).
4. Bradleya andamanae, new species; left valve adult showing a very coarse reticulum forming a
median ridge traversing the entire length of the side, a posterior ventral segment of the bridge,
and an eye tubercule; Recent, Oceanographer station OSS-01, 260G in the Andaman Sea, lat.
06°39.4'N, long. 98°52.0'E, 78 meters; holotype USNM 174322 (x85).
5. Bradleya nuda, new species; left valve of adult showing absence of muri except for faint traces
of parts of the reticular pattern similar to that of the specimen in Plate 7: figure 3; upper Pliocene,
Okuwa, Kaga Province, Japan; Ozawa locality F25510; holotype USNM 174323 (x50).
6. Bradleya mackenziei, new species; left valve adult, a small form with prominent and sharp
ocular, dorsal and ventrolateral carinae and remnants of the bridge, fossae quite angular to "ragged",
eye tubercule; Recent from Australia, Bass Strait, McKenzie sample M290; holotype
USNM 174324 (x65).
7. Bradleya paranuda, new species; left valve adult showing produced anterior, smooth surface
except for the remaining traces of reticular pattern extending from the dorsal and ventral carinae
and two near the posterior; Recent, Albatross station ALB 5250, Gulf of Davao, Philippine
Islands, lat. 7°05'07"N, long. 125°39'45"E; 23 fathoms; holotype USN M174325 (x70).
8. Bradleya normani (Brady, 1865) left valve of adult showing a geographic variation of reticulum
development (secondary reticulation) and with a slight indication of the bridge structure
and a poorly developed ocular ridge; Recent, Straits of Magellan, R-V Hero station 57 (Cruise
69-5), 117 fathoms; USNM 174326 (x60).
NUMBER 1 2 123
124 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
PLATE 8
1. Jugosocythereis species; left valve of adult showing a well-developed bridge developed from
the muscle-scar node region forward, the posterodorsal loop formed by dominant muri, and the
similarity of the reticular pattern with those of Bradleya; Recent, Indian Ocean, Grand Comoro
Island, 40 feet; USNM 174333 (x65).
2. Bradleya (Quasibradleya) prodictyonites, new species, left valve of adult showing variation in
the strong ocular, dorsal and ventrolateral carinae, a disjunct bridge and median ridge continuing
toward posterodorsum to form loop; lower Oligocene, New Zealand, Hornibrook sample
F5052; holotype USNM 174327 (x55).
3. Bradleya (Quasibradleya) paradictyonites, new species; left valve adult showing massive muri,
eye tubercule, "eared" posterodorsum and median ridge with diminished ventral portion of the
bridge, Oligo-Miocene Fossil Bluff locality near Wynyard Beach, northern Tasmania; holotype
USNM 174328 (x65).
4. Bradleya (Quasibradleya) dictyonites, new species (for B. dictyon of Hornibrook); left
valve adult with strong ocular-ventrolateral and dorsal carinae, "eared" posterodorsum, eye tubercule,
disjunct median ridge and remnants of lower portion of bridge; upper Oligocene (Awamoah),
New Zealand, Old Rifle Butts section, Hornibrook locality F6487; USNM 174328
(x55).
5. Poseidonamicus major, new species; an adult left valve with coarse vertical muri and enlarged
bullate muscle-scar node; lower Miocene, South Atlantic, DSDP III, Hole 15, core 8, section 3
(see Table 2), holotype USNM 174329 (x65).
6. Bradleya normani (Brady, 1865) ; a small adult left valve showing increased mass in the muri
and decreased secondary reticulation (see Figure 4 and Plate 7: figure 8); Recent, Galapagos
Islands, Albatross station, ALB 2817, 271 fathoms; USNM 174330 (x40).
7—8. Bradleya dictyon (Brady, 1880) ; two variations in form of this cosmopolitan species (7)
USNM 174331 (x65) from lower Miocene of the South Atlantic (DSDP III, Hole 15, core 8,
section 3) showing traces of the median ridge and (8) USNM 174382 (x45) from the continental
slope of northern Chile (ELT 63; lat. 25°44'S; long. 70°58'W; 1863 meters) showing a
typical expression of the muri. This specimen is the one from which the soft parts were removed
to be drawn for Figures 16 and 17.
NUMBER 12 125
126 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
PLATE 9
1-12. Bradleya dictyon (Brady, 1880). Scanning Electron Micrographs of the left valve of a
female specimen from Mozambique Channel (1) showing a full lateral view (box is view of
Plate 9: figure 7); (2) posterior and (3) anterior views; (4) a conjunctive pore conulus
(arrowed in Plate 9: figure 5) on a foveolate junction of the ventrolateral ridge and a supporting
murus; (5) a ventromedian segment of the carapace; (6) a celate sieve pore (arrowed in
Plate 9: figure 5) on a caperate solum; (7) the muscle-scar node region (boxed in Plate 9:
figure 1) showing the thaerocytherid muscle-scar pattern, the local reticular pattern with three
pore conuli mounted on the muri and the posterior section of the bridge structure; (8) an
oblique view of the foveolate muri and (9) an enlargement of the foveolation and (10) a
strongly celate pore (arrowed in Plate 9: figure 8 ) ; (11) the ocular region and (12) posterodorsum.
Scales = 1, 10, 100 microns.
NUMBER 12 127
128 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
PLATE 10
1-6. Poseidonamicus major, new species; paratypes (USNM 174354) as seen in reflected and
transmitted light (1, 4) left valve, adult male; (2, 5) right valve, adult male; (3, 6) left valve,
adult female. From Mozambique Channel, IIOE station 366A, lat. 23°9'S and long. 43°9'S and
long, 43°9'E; 2300 meters; (x45).
7-12. Poseidonamicus pintoi, new species; separate valves of whole specimen as seen in (7) black
light, (10) transmitted and (8, 9, 11, 12) reflected light; (7, 8, 10) right valve, female, paratype;
(12) interior showing hinge, USNM 174356; (9) paratype left valve female (specimen
lost); (11) holotype, left valve female, USNM 174355. From the continental shelf off Brazil;
Albatross station 2763, lat. 24°17'S and long. 42°43'30'W; 671 fathoms; (x50).
13-18. Poseidonamicus minor, new species; two separate valves of the same specimen (13, 16)
holotype, left valve, adult, USNM 174357; (14, 17) paratype, right valve, adult, USNM
174358, from the southeastern Pacific, Down Wind Expedition station DWBG 74, lat. 28°43'S
and long, 107°36'W; 3220 m; and (15, 18 [dorsal view]), penultinate instar, right valve, paratype
USNM 174359. From southeastern Pacific, Eltanin station 21-10, lat. 36°41'S and long,
93°37'W, 3137 meters; (x50).
NUMBER 12 129
130 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
PLATE 11
1—11. Poseidonamicus nudus, new species; as seen in (1) reflected and (2, 3) transmitted light;
adult whole specimen (holotype USNM 174351) with valves divided; (1) right valve, (2) right
and (3) left valves; (4-9) stained paratypes, right valve, adult, exterior view and showing several
views of the hinge, USNM 174352; (10) anterior marginal area, (11) muscle-scar and reticular
pattern of right and left valves. From the Mozambique Channel, IIOE station 367G, lat.
22°42'S and long. 40°21'E, 3140 meters (x40).
12—14. Poseidonamicus major, new species: (12) carapace of dissection 297, USNM 174353;
Eltanin station 1248; (13) late instar from Mozambique Channel, IIOE 416A, USNM 174381;
(14) left valve from above sample as seen in transmitted light for comparison of reticular pattern
as seen in Plate 11: figure 11 (x45).
15. Poseidonamicus viminea (Brady, 1880), nomen dubium (see p. 50); holotype by monotypy,
BM 80.5.33, from Challenger station 146 near Prince Edward Island (unstained, x55).
16-17. Bradleya arata (Brady, 1880), lectoparatype, a penultimate instar, BM 80.38.52, from
Challenger station 167 in the Tasman Sea, as seen from (16) exterior and (17) interior views
(unstained, x50).
18. Bradleya dictyon (Brady, 1880), the lectoholotype (designated herein), an adult left valve,
BM 161.12.4.32, from Challenger station 78, North Atlantic, lat. 37°24'N and long. 25°13'W,
1000 fathoms (x40).
NUMBER 12 131
132 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
PLATE 12
1-10. Agrenocythere spinosa, new species; (1) exterior lateral view and (2) anterior end view of
left valve of paratype (USNM 174336, from IIOE 407, Recent), with (3) enlargements of the
castrum, (4) the porus castri (arrowed in Plate 12: figure 1), (5) the sieve plate of the porus
castri and setal mount, (6) a section (boxed in Plate 12: figure 1) of the ponticulum forming
the ventrolateral ridge, and (8) the region of the ocular ridge. (9) Paratype, USNM 174365,
from IIOE 365D, Recent, is shown in lateral view, with (7) enlargements of the ocular region
showing the pore conulus Aquarius, and (10) the castral region (boxed section in Plate 12:
figure 9). Scales = 1 0 and 100 microns.
NUMBER 1 2 133
1 3 4 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
PLATE 13
1-6. Agrenocythere radula (Brady, 1880), (1) lateral view, (2) posterior view, (3) anterior
view, and (6) the ventral of right valve, with (4) enlargements of the castrum and (5) spicula
(arrowed in Plate 13: figure 1). From the Recent of Mozambique Channel, IIOE 410A, hypotype
USNM 174341.
7-11. Agrenocythere hazelae (van den Bold, 1946), from the eastern Pacific, ALB 3375, USNM
174342. (9) Lateral view, (7) enlarged and in (11) anterior view, with (8) enlargements of the
castrum and (10) anterior pore conulus and intramural pore (arrowed in Plate 13: figure 7).
Scales = 10 and 100 microns.
NUMBER 12 135
136 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY
PLATE 14
1-4. Agrenocythere radula (Brady, 1880); (1) exterior left valve of hypotype (USNM 168377,
IIOE 363B) ; (2) exterior right valve of hypotype (IIOE 363B); (3) interior and (4) exterior
of left valve of hypotype (USNM 174360, IIOE 363B; Mozambique Channel).
5. Agrenocythere spinosa, new species, left valve of paratype, USNM 174366, IIOE 407D; Mozambique
Channel.
6, 10-15. Agrenocythere americana, new species, paratypes USNM 174363, from ALB 2383,
Gulf of Mexico; (6) exterior view of left valve of male paratype; (10) exterior view and (13)
interior view of right valve of male paratype; (11) exterior view and (14) interior view of right
valve of female paratype; (12) exterior view and (15) interior view of left valve of female paratype.
7—9. Agrenocythere hazelae (van den Bold, 1946); (7) exterior view, (9) interior view and (8)
enlargement of the central reticulum of a right valve of a male(?) paratype, USNM 174364;
ALB 3375; eastern Pacific.
16-18. Agrenocythere radula (Brady, 1880), designated lectoholotype (left valve, penultinate instar)
from the original Brady material of the Challenger Expedition (BM 81.5.28) collected
from station 191A, Ki Islands, southern Indonesia at 580 fathoms depth, as seen in (16) exterior
lateral, (17) exterior dorsal, and (18) interior views.
All illustrations on this plate were made by light photography and are approximately 35x magnifications
except Figure 8, which is about 80x.
NUMBER 12 137
Index
(Principal page entries in italics)
aculeata, 17, 18, 27, 60, 83, 90
Agrenocythere, 4, 17, 21, 23, 58
"Agrenocythere" problem, 3
albatrossia, 39
americana., 73
andamanae, 15, 30, 40
antiquata, 26, 84
Aquarius, 59
arata, 2, 16, 30, 33
architectural form, 7, 16
arx, 58
ballium, 58
Bradleya, 10, 11, 17, 21, 28
"Bradleya" problem, 2
Bradleyinae, 28
bridge, 29
bullar series, 58
cadoti, 26, 86
Capricornus, 59, 64
Carino cythereis, 12
castrum, 56, 58
celation, 29, 30, 34
character development, 10
Charon, 59, 84, 86
Cistacythereis, 12
Cletocythereis, 18, 22, 26, 27, 62, 78
crenulata (Thaerocythere), 27
Cythereis, 6, 10, 21, 62
dictyon, 1, 15, 32, 34
dictyonites, 16, 44
ducassae, 27, 62, 95
forum, 56, 58
fossa arcis, 58, 84
fossal pattern, 4, 5
gosnoldia, 78
haidingerii, 17, 23, 26, 28
hazelae, 4, 17, 24, 64
Hermanites, 12, 17, 18, 27, 28, 95
hinges, 11
Historical critique, 10
Hornibrookella, 27, 28, 95
Illustration, 4
japonica, 40
Jugosocythereis, 12, 16, 21, 27
Leo, 59, 64, 83, 84
Limburgina, 12, 17, 18, 27, 56, 62
loop, 29, 49
major, 52
material, 8
mckenziei, 15, 42
median ridge, 56
Messinian "crisis", 26
minor, 53
monothetic, 8, 12
morphologic trends, 13
mural accommodation, 16
muscle scars, 11,12
normani, 3, 15, 38
nuda, 41
nudus, 54
Oertliella, 7, 26, 89
ornament style, 3
paradictyonites, 16, 45
paranuda, 42
parapectus, 58
pattern analysis, 4
pattern causes, 5
pervial fossa, 58, 84
pintoi, 53
plicocarinata, 16, 46
pliocenica, 2, 12, 23, 24, 77
polythetic, 8, 13
pore conuli, 6, 58
porus castri, 58
Poseidonamicus, 4, 16, 17, 21, 46
Procythereis, 27, 28
prodictyonites, 16, 45
Quadracythere, 12, 27, 32
Quasibradleya, 28, 33, 43
radula, 3, 23, 26, 74
rampart, 58
rastromarginata, 23, 28, 56
reductionism, 4, 5
reticular field, 16, 48, 58
reticular pattern, 4, 16
reticulata (Hermanites), 18, 28, 90
reticulata (Oertliella), 19, 23, 61, 90
samples, 8
semivera, 3, 4, 11, 12, 89
senility, 38
specimens, 8
specula, 58
spinosa, 23, 64
telisaensis, 15, 42
Thaerocytheridae, 27
Trachyleberidea, 17, 62
Trachyleberididae, 55
Trachyleberidinae, 55
viminea, 3, 50
•&U.S. Government Printing Office: 1972 0—448-827
138


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