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Displaying 1 - 10 from the 644 total records
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Additions to Revisions of the Blenniid Fish Genera Ecsenius and Entomacrodus, with Descriptions of Three New Species of Ecsenius
Victor G. Springer
13 pages, 3 figures, 4 tables
1972 (Date of Issue: 25 October 1972)
Number 134, Smithsonian Contributions to Zoology
DOI: 10.5479/si.00810282.134
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Abstract

New distribution records and supplemental data on species of Ecsenius and Entomacrodus are given with reference to recent revisions of these genera by Springer (1967, 1971). Three new species of Ecsenius are described and illustrated: Ecsenius (Ecsenius) collettei, from New Guinea, Ecsenius (Ecsenius) fourmanoiri, from New Caledonia, and Ecsenius (Ecsenius) trilineatus from the Banda Sea and New Guinea. A revised key to the species of Ecsenius is provided.


Additions to the Family Eulepethidae Chamberlin (Polychaeta: Aphroditacea)
Marian H. Pettibone
51 pages, 42 figures
1986 (Date of Issue: 12 September 1986)
Number 441, Smithsonian Contributions to Zoology
DOI: 10.5479/si.00810282.441
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Abstract

The previous revisionary study of the family Eulepethidae by Pettibone (1969) is supplemented, based on additional available material, including young stages. Two new genera, five new species, and two new combinations are added to the family.


Age Determination of Loggerhead Sea Turtles, Caretta caretta, by Incremental Growth Marks in the Skeleton
George R. Zug, Addison H. Wynn and Carol Ruckdeschel
34 pages, 9 figures, 6 tables
1986 (Date of Issue: 25 July 1986)
Number 427, Smithsonian Contributions to Zoology
DOI: 10.5479/si.00810282.427
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Abstract

Periosteal growth in the skeleton of Caretta caretta is cyclic and produces a record of distinct bony layers (growth marks). These layers are most apparent in the long bones, particularly the humerus and femur. Correlative evidence supports the production of one layer (i.e., growth increment) each year in some reptiles, and the annual nature of each bony layer is an explicit assumption in our estimation of ages of Caretta from Cumberland Island, Georgia. Sections from the shafts of humeri were prepared with standard histological techniques, and the marks of skeletal growth were counted and measured. Owing to resorption of the early periosteal layers, determination of number of growth marks and, hence, age requires an extrapolation from the remaining marks to total growth marks produced during the life of the turtle. Various age estimates are possible; the most reliable are derived from the narrowest axis of the humerus sections and suggest that, on the average, Georgia Caretta attain sexual maturity in their thirteenth to fifteenth years, with some individuals possibly maturing as early as six years and others as late as their twenty-fifth year. Since the average age of maturity agrees with the results of a mark-recapture study in a neighboring Florida population, the value of the skeletochronological technique and its assumptions are confirmed. The technique is not advocated as a method for the age determination of individual sea turtles, but does provide statistical age estimates for different size classes of turtles.


An Analysis of Nesting Mortality in Birds
Robert E. Ricklefs
48 pages, 11 figures, 26 tables
1969 (Date of Issue: 12 December 1969)
Number 9, Smithsonian Contributions to Zoology
DOI: 10.5479/si.00810282.9
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Abstract

This study was initiated to evaluate nesting mortality of birds as a feature of the environment and as a selective force in the evolution of reproductive strategies. Representative nesting-success data from the literature for most groups of birds were transformed into daily mortality rates to eliminate differences among species in the length of the nest cycle. These data are presented by taxonomic groupings and for passerines by geographical region and nest construction and placement.

The strength and pattern of various mortality factors are described in detail. Predation, starvation, desertion, hatching failure, and adverse weather are the most prevalent factors, but nestsite competition, brood parasitism, and arthropod infestation may be important in some species. It is demonstrated that the various mortality factors can be identified by characteristic patterns of nesting losses involving differences in mortality rates between the egg and nestling periods and the within-nest component of mortality rates.

Among Temperate Zone passerines, field-nesting and marsh-nesting species have the highest mortality rates while those species nesting in trees, especially in cavities, enjoy higher success. Starvation is prevalent in marsh and field species but desertion is more restricted to tree-nesting species. In general, arctic species have lower mortality rates and tropical species higher rates, although there is a similar gradient from arid to humid regions within the tropics. The relative abundance of a species is related directly to its mortality rate in arctic regions, but is not in temperate and tropical regions.

Birds of prey generally have low mortality rates although starvation is often a major factor. Nesting losses in seabirds are caused primarily by crowded conditions in colonies and loss of eggs due to inadequate nest construction. Chick deaths come about primarily through their wandering away from parental care which is most common in the semiprecocial Charadriiformes. Precocial shorebirds and water birds enjoy higher egg success than ground-nesting passerines but game birds exhibit similar mortality rates. Little is known of the survival of precocial chicks after hatching except that mortality rates may be initially quite high and decrease with age. The fate of altricial birds after fledging is also poorly documented.

It is postulated that interspecific differences in mortality rates are determined by evolutionarily acceptable levels of adult risk to lower mortality rates of offspring through parental care, adult adaptations of morphology and behavior for foraging which result in limitations on nesting adaptations, environmental unpredictability which reduces the effectiveness of adaptations, and—most import—the diversity of predators to which a species must adapt.


Analysis of the Intergeneric Relationships of the Australian Frog Family Myobatrachidae
W. Ronald Heyer and David S. Liem
29 pages, 28 figures, 2 tables
1976 (Date of Issue: 9 September 1976)
Number 233, Smithsonian Contributions to Zoology
DOI: 10.5479/si.00810282.233
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Abstract

Forty-two characters of external morphology, myology, osteology, and life history are studied. For each character, the evolutionary directions of changes of states are inferred. This information is used to construct a phylogenetic hypothesis of the intergeneric relationships of the primarily Australian frog family Myobatrachidae. Three major groupings of myobatrachids are proposed; these are accorded subfamilial status. One of the subfamilies is defined as new. In addition, three genera are proposed as new.

It is proposed that the ancestral myobatrachid stock was associated with the Antarcto-Tertiary Geoflora. Several genera still demonstrate a distribution associated with this beech-podocarp vegetation. Major evolutionary events in the family have been associated with stream adaptations, trends toward and including direct development and fossorial adaptations. Convergence in these events with the leptodactylid frog fauna of southern South America is commented upon.


Anatomy of the External Nasal Passages and Facial Complex in the Delphinidae (Mammalia: Cetacea)
James G. Mead
72 pages, 26 figures, 3 tables
1975 (Date of Issue: 18 November 1975)
Number 207, Smithsonian Contributions to Zoology
DOI: 10.5479/si.00810282.207
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Abstract

This study is concerned with the comparative anatomy of the external nasal passages and associated structures in delphinid odontocetes. It has been possible to assemble detailed antomical information for nearly all of the delphinid genera. Comparative data for the other small toothed whales is considered in such detail as is available.

The function of the structures associated with the external nasal passages has been poorly understood, partly due to a lack of understanding of their anatomy. I have drawn functional conclusions from the basis of this comparative study, but these are largely unsupported by experimental data.

The nasal musculature is concerned both with opening and closing the nasal passage during respiration, and with movement of air between the nasal diverticula during sound production. The nasal diverticula are part of the acoustic system of these animals, and function both as air reservoirs and as reflective elements to focus the emitted sound field. The potential area of sound production is limited to the deep structures around the external body nares. The melon probably serves as an acoustic channel. Cranial asymmetry in odontocetes is related to specialized sound-producing mechanisms involving predominantly the right nasal passage.

The nasal structures have formed a very important functional complex in the evolution of odontocetes, and are important from a phyletic viewpoint. This study has shown that the genera Tursiops, Stenella, and Delphinus form a relatively generalized group within the Delphinidae. The bulbous-headed genera Grampus, Globicephala, and Pseudorca clearly represent independent specializations. The other families of odontocetes differ considerably from the delphinids in their facial anatomy.

The anatomical diversity in this region suggests an acoustic diversity which remains to be demonstrated experimentally.


Anatomy, Reproductive Biology, and Phylogeny of the Planaxidae (Cerithiacea: Prosobranchia)
Richard S. Houbrick
57 pages, 27 figures, 6 tables
1987 (Date of Issue: 18 March 1987)
Number 445, Smithsonian Contributions to Zoology
DOI: 10.5479/si.00810282.445
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Abstract

The family Planaxidae Gray comprises a small, monophyletic, mainly pantropical marine group of six extant genera in the superfamily Cerithiacea Fleming that are adapted to an intertidal environment. They are microphagous herbivores and usually occur in large populations on hard substrates. Planaxids are gonochoristic and have open pallial gonoducts, aphallic males, produce spermatophores, and brood their young in specialized cephalic brood pouches of ectodermal origin. Embryos of most species are released at the veliger stage and undergo a planktotrophic phase before settlement, but some species undergo a direct, lecithotrophic development. Species in the genus Angiola are unique among prosobranchs in having a bioluminescent mantle organ.

On the basis of morphological homology, ontogeny, and advocacy, Batillaria (of the subfamily Batillariinae, family Potamididae) and Melanoides (of the freshwater family Thiaridae) were chosen as outgroups for phylogenetic analysis of all genera except Holcostoma. The polarities of characters were established by outgroup comparison, and transformation series of multi-state characters were ordered by structural complexity and by reciprocal illumination. Two equally parsimonious cladograms were produced that arrange the taxa in essentially similar sequence. Planaxis and Fissilabia share many apomorphies as do Angiola and Hinea. Six recent genera are recognized as comprising the Planaxidae: Planaxis Lamarck, 1822; Fissilabia Macgillivray, 1836; Supplanaxis Thiele, 1929; Hinea Gray, 1847; Angiola Dall, 1926; Holcostoma H. and A. Adams, 1853. Synonymies, conchological, radular and anatomical descriptions, and the ecology and life histories of each genus are presented.


Anchialine Ostracoda (Halocyprididae) from San Salvador, Bahamas
Louis S. Kornicker and Douglas J. Barr
20 pages, 11 figures, 3 tables
1997 (Date of Issue: 24 February 1997)
Number 588, Smithsonian Contributions to Zoology
DOI: 10.5479/si.00810282.588
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Abstract

Spelaeoecia barri Kornicker, new species, an anchialine halocyprid Ostracoda (Halocyprididae: Deeveyinae), is described and illustrated from collections made at Dixon Hill Lighthouse Cave, San Salvador, Bahamas. Descriptions of adults and four juvenile stages are included and a discussion of ontogeny is given. A key to species of Spelaeoecia also is presented.


Angulorostrum, a New Genus of Myodocopid Ostracoda (Philomedidae: Pseudophilomedinae)
Louis S. Kornicker
20 pages, 11 figures, 2 plates
1981 (Date of Issue: 19 October 1981)
Number 340, Smithsonian Contributions to Zoology
DOI: 10.5479/si.00810282.340
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Abstract

A new genus, Angulorostrum, in the subfamily Pseudophilomedinae is proposed, and three new species referred to the genus are described and illustrated. The new species are from the continental slope of the Atlantic Ocean at depths of 210 to 1007 meters off Brazil, North Carolina, South Carolina, Portugal, and Spain. Keys are presented to the genera of Pseudophilomedinae and to the species of Angulorostrum.


Anisochromis straussi, New Species of Protogynous Hermaphroditic Fish, and Synonymy of Anisochromidae, Pseudoplesiopidae, and Pseudochromidae
Victor G. Springer, C. Lavett Smith and Thomas H. Fraser
15 pages, 2 figures, 4 tables
1977 (Date of Issue: 25 August 1977)
Number 252, Smithsonian Contributions to Zoology
DOI: 10.5479/si.00810282.252
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Abstract

Anisochromis straussi is described from the isolated St. Brandon's Sholas in the southwestern Indian Ocean. The species exhibits two types of color patterns, which are correlated to some degree with size and sex. Histological sections of the gonads indicate that all testes have a nonfunctional cavity that represents the remnant of the ovarian lumen, and all have remnants of oocytes among the acini. The smaller specimens are female, the larger, males. Evidence is presented that the Anisochromidae, Pseudoplesiopidae, and Pseudochromidae form a monophyletic group. Evidence is also presented that within this group the Pseudoplesiopidae and Anisochromidae form a monophyletic group and each of these two taxa is definable based on autapomorphies. The Pseudochromidae appear to be a possibly polyphyletic primitive residue group that is not definable on the basis of autapomorphies. The lowest phylogenetic level for which there is evidence of monophyly among the fishes currently assigned to the Anisochromidae, Pseudoplesiopidae, and Pseudochromidae was chosen as the level for family recognition. Pseudochromidae is the oldest family-group name available for this level.


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