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Index of Living and Fossil Echinoids 1924-1970
Porter M. Kier and Mary Hurd Lawson
182 pages
1978 (Date of Issue: 10 February 1978)
Number 34, Smithsonian Contributions to Paleobiology
DOI: 10.5479/si.00810266.34.1
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All new taxa of fossil and living echinoids described from 1924 to 1970 are listed with their age, geographic and stratigraphic occurrence, and bibliographic citation.

Jurassic Brachiopods of Saudi Arabia
G. Arthur Cooper
213 pages, 48 figures, 37 plates
1989 (Date of Issue: 13 July 1989)
Number 65, Smithsonian Contributions to Paleobiology
DOI: 10.5479/si.00810266.65.1
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No studies in depth have been made of the brachiopods from the Jurassic deposits of Saudi Arabia. This first study of the brachiopods from this important region is based mainly on a collection presented to the Smithsonian Institution by the Arabian-American Oil Company (Aramco). In addition, the study includes collections made by Drs. P.M. Kier and E.G. Kauffman of the Smithsonian Institution and R.W. Powers, C.D. Redmond and H.A. MacClure of the Arabian-American Oil Company.

Sixty-one genera are described of which 29 are new. Of these 13 rhynchonellid genera are new: Amydroptychus, Baeorhynchia, Colpotoria, Conarosia, Deltarynchia, Echyrosia, Eurysites, Heteromychus, Lirellarina, Nastosia, Pycnoria, Schizoria, and Strongyloria. Other described genera are: Burmirhynchia Buckman, 1917, Cymatorhynchia Buckman, 1917, Daghanirhynchia Muir-Wood, 1935, Gibbirhynchia Buckman, 1917, Globirhynchia Buckman, 1917, Kallirhynchia Buckman, 1917, Kutchirhynchia Buckman, 1917, Somalirhynchia Weir, 1925, Sphenorhynchia Buckman, 1917, and Torquirhynchia Childs, 1969.

Of Spiriferinacea, one genus, Calyptoria, is new and two genera are described: Liospiriferina Rouselle, 1977, and Spiriferina d'Orbigny, 1847. The Terebratulacea are represented by 11 new genera: Arabatia, Arabicella, Arapsopleurum, Arapsothyris, Dissoria, Ectyphoria, Pionopleurum, Pleuraloma, Stenorina, Tanyothyris, and Toxonelasma. Seventeen described terebratulaceans are Apatecosia Cooper, 1983, Avonothyris? Buckman, 1917, Bihenithyris Muir-Wood, 1935, Dolichobrochus Cooper, 1983, Dorsoplicathyris? Almeras, 1971, Glyphisaria? Cooper, 1983, Gyrosina? Cooper, 1983, Habrobrochus Cooper, 1983, Kutchithyris? Buckman, 1917, Loboidothyris? Buckman, 1917, Orthotoma Quenstedt, 1869, Plectothyris? Buckman, 1917, Pseudowattonithyris? Almeras, 1971, Somalithyris Muir-Wood, 1935; Sphaeroidothyris Buckman, 1917, Stiphrothyris? Buckman, 1917, and Striithyris Muir-Wood, 1935.

The Zeilleriacea include four new genera: Apothyris, Mycerosia, Sphriganaria and Xenorina. Described zeilleriids are Flabellothyris Eudes-Deslongchamps, 1884, Rugitela Muir-Wood, 1936, and Zeilleria Bayle, 1878. A total of 166 species are described and 25 lots are identifiable as species.

Pseudoglossothyris? sulcata Muir-Wood, 1935, from Somaliland (Somali Republic) is shown to be a zeilleriid, and the species is herein transferred to Aulacothyris. Eudesia cardioides Douvillé, 1916, is herein transferred to the new genus Sphriganaria.

The Liassic Marrat Formation abounds in spiriferinids. The Dhruma Formation (Bajocian to Callovian) is rich in rhynchonellids which dwindle in numbers in late Dhruma beds. The overlying Tuwaiq Mountain and Hanifa formations (Callovian to Kimmeridgian) are conspicuous for the large numbers of terebratulaceans which far outnumber the rhynchonellids.

Correlation with Jurassic sequences near and far is difficult because of the high degree of endemism shown by the Saudi Arabian brachiopods. Precise correlation with British and European faunas is not now possible. Relationships with the Jurassic faunas of the Sinai, Israel and East Africa in the Callovian is suggested by the presence of two species in common and generic representation shown by Daghanirhynchia, Somalirhynchia, Bihenithyris, Somalithyris, and Striithyris.

Jurassic Rhynchonellids: Internal Structures and Taxonomic Revisions
Xiao-ying Shi and Richard E. Grant
190 pages, 83 figures, 18 plates
1993 (Date of Issue: 1 November 1993)
Number 73, Smithsonian Contributions to Paleobiology
DOI: 10.5479/si.00810266.73.1
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Jurassic brachiopods of the order Rhynchonellida are classified according to modern concepts and techniques, with special attention to internal structures. They are grouped into 6 families and 16 subfamilies of which three are new: the Acanthorhynchiinae, the Cryptorhynchiinae, and the Piarorhynchiinae. Subfamilies emended or revised are the Acanthothyridinae Schuchert (1913) raised to family rank, Davanirhynchinae Ovtsharenko (1983), Dzhangirhynchinae Ovtsharenko (1983), Erymnariinae Cooper (1959), Indorhynchiinae Ovtsharenko (1975), Septocrurellinae Ager, Childs, and Pearson (1972), and Striirhynchiinae Kamyshan (1968). New genera are Aalenirhynchia (type-species Rhynchonella subdecorata Davidson, 1853), Bradfordirhynchia (type-species Cryptorhynchia bradfordensis Buckman, 1918), and Sharpirhynchia (type-species Kallirhynchia sharpi Muir-Wood, 1938). A new subgenus is Burmirhynchia (Hopkinsirhynchia) (type-species Burmirhynchia hopkinsi Davidson, 1854). The only new species is Pycnoria depressa. Eleven genera are revised, and many are transferred among the subfamilies; lectotypes are designated where needed.

Living and Fossil Brachiopod Genera 1775-1979: Lists and Bibliography
Rex A. Doescher
238 pages
1981 (Date of Issue: 19 November 1981)
Number 42, Smithsonian Contributions to Paleobiology
DOI: 10.5479/si.00810266.42.1
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All genera and subgenera of fossil and living brachiopods described from 1775 to 1979 are listed with comments on their current nomenclatural status. A computerized list presents all valid brachiopod genera (and subgenera), including subjective synonyms, with additional information regarding type-species, superfamily classification, and range (by period) of each genus. A bibliography supplements both lists.

A Lower Eocene Frigatebird from the Green River Formation of Wyoming (Pelecaniformes: Fregatidae)
Storrs L. Olson
33 pages, 31 figures
1977 (Date of Issue: 7 October 1977)
Number 35, Smithsonian Contributions to Paleobiology
DOI: 10.5479/si.00810266.35.1
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A new subfamily, Limnofregatinae, is erected for the first known Tertiary specimens of the pelecaniform family Fregatidae. These are described as a new genus and species, Limnofregata azygosternon. The holotype is a nearly complete skeleton with feather impressions. Two additional specimens, consisting of a partial skeleton and a fragment of ulna, are referred to the same species. All are from freshwater lake deposits in the Lower Eocene Green River Formation of Wyoming, which are roughly 50 million years old. The principal differences between Limnofregata and modern frigatebirds (Fregata) are seen in its shorter and less hooked rostrum, proportionately shorter wings and longer hindlimb, in the lack of fusion in the pectoral girdle, and in the lack of extensive pneumatization of the skeleton. The fossilform is, nevertheless, well advanced along the lines of modern frigatebirds and nothing in its morphology seems to preclude its being ancestral to Fregata. The fossil provides additional support for placing the suborder Fregatae between the more primitive tropicbirds (suborder Phaethontes) and the members of the suborder Pelecani. Frigatebirds in the early Tertiary evidently occupied different habitats or a wider range of habitats than the modern forms and have only subsequently been restricted to a purely oceanic environment.

Mammalian Faunal Zones of the Bridger Middle Eocene
C. Lewis Gazin
25 pages
1976 (Date of Issue: 20 January 1976)
Number 26, Smithsonian Contributions to Paleobiology
DOI: 10.5479/si.00810266.26.1
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The zoning arrangement of the Bridger Middle Eocene as defined by W. D. Matthew in his 1909 monograph on the Carnivora and Insectivora of the Bridger Basin included a series of stratigraphic units lettered from A to E. The type section is in the western part of the basin but correlation of the sequence in the eastern part of the basin erred in that a very large area shown by Matthew as C, or upper Bridger, is actually B, or lower Bridger. As a consequence many of the mammalian remains collected in the eastern part of the basin were attributed to the wrong horizon. This was discovered in my faunal studies and verified by Wilmot Bradley's mapping of the Sage Creek White Layer, which is the base of Bridger C or upper Bridger.

A faunal list of the Mammalia recognized in the Bridger is given with type localities and their horizons, so far as known, and the number of specimens in the National Museum of Natural History collections from each of the two divisions, lower and upper. Following this a discussion of species is given in which the evidence for any species being restricted to one or the other of the stratigraphic divisions is cited, or such information demonstrating its occurrence in both levels, if this is not indicated by the National Museum of Natural History collections (under the catalog numbers of the old United States National Museum).

The Annotated Bibliography includes references to all papers in which recognized new mammalian families, genera, and species included in the Bridger faunas are described. Also included are papers in which stratigraphic and additional or detailed information on Bridger mammals is provided, with notations as to extent of coverage, and possible errors of detail or interpretation in certain cases.

Megaspores and a Palynomorph from the Lower Potomac Group in Virginia
Francis M. Hueber
69 pages, 1 figure, 24 plates
1982 (Date of Issue: 22 February 1982)
Number 49, Smithsonian Contributions to Paleobiology
DOI: 10.5479/si.00810266.49.1
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A plant microfossil assemblage comprising seven species of megaspores; Verrutriletes carbunculus (Dijkstra) Potonié, Echitriletes cf. E. lanatus (Dijkstra) Potonié, Erlansonisporites erlansonii (Miner) Potonié, Thylakosporites retiarius (Hughes) Potonié, Arcellites disciformis (Miner) Ellis and Tschudy, Arcellites cf. A. pyriformis (Dijkstra) Potter, and Paxillitriletes species Hall and Nicolson; two species of the microspore Crybelosporites Dettmann, C. striatus (Cookson and Dettmann) Dettmann adherent to specimens of Arcellites disciformis, and Crybelosporites species adherent to specimens of Echitriletes cf. E. lanatus; and the palynomorph Dictyothylakos pesslerae Horst; is recorded from the Patuxent Formation, Potomac Group, Lower Cretaceous (Barremian-Aptian) in Virginia, USA. A preliminary analysis of the enclosing matrix for microspores and pollen has related the collection site closely to lowermost Zone I of the Potomac Group as described by Hickey and Doyle (1977). The megaspore assemblage supported by acceptance of the oldest possible date derived from the microspore and pollen analysis suggests correlation with the Barremian-Aptian horizons in the English Wealden, Lower Cretaceous, and specifically with the “Arcellites Flora” of Hughes. Megafossils comprising two seed cones belonging to the Pinaceae, Pityostrobus hueberi Robison and Miller and Pityostrobus virginiana Robison and Miller have been reported from the site. A fruit or cupule of Caytonia has been found along with numerous seeds, fern fragments, coniferous woods, and cycadopsid cuticles. This array of megafossils is not described or illustrated herein. A backswamp area of sedimentation and type of habitat is suggested on the basis of the lithofacies and generalized composition of the flora. The writer fully agrees with Tschudy (1976) as to the importance of searching for megaspores in continental Mesozoic rocks to aid in correlating and subdividing the deposits more effectively.

Microdistribution of Foraminifera in a Single Bed of the Monterey Formation, Monterey County, California
Roberta K. Smith and Martin A. Buzas
33 pages, 4 figures, 2 plates, 7 tables
1986 (Date of Issue: 27 October 1986)
Number 60, Smithsonian Contributions to Paleobiology
DOI: 10.5479/si.00810266.60.1
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While several papers exist on the small scale spatial distribution of living foraminifera, almost no work exists on the small scale spatial distribution of fossils. The present study took 24 (5 ml) replicates 10 cm apart along one bed of the Monterey Formation in California.

The mean density for all replicates is 6084.96 with a standard deviation of 8776.95. Both inspection and a cluster analysis of the data indicate replicates 20-24 have a much higher density and different rank order of abundance than replicates 1-19. The mean density for the total of all species in replicates 1-19 is 2387.47 with a standard deviation of 1175.58. For replicates 20-24 the mean density is 20135.40 with a standard deviation of 11181.40. The spatial variability is so great that four replicates (more than commonly taken) would only allow us to be 95% confident that we are within 50% of the true mean. Because age determination is based on presence of particular taxa rather than on densities, stratigraphic assignment would still be possible.

The three species dominating the 1-19 group make up from 86% to 99% of the fauna. The three species dominating the 20-24 group make up from 77% to 85% of the fauna. Two of these are also dominant in the 1-19 group, but the most dominant species in the 20-24 group constitutes only <1% to 8% in the 1-19 group.

The greatest number of species (22) occurs in the 20-24 group, as would be expected from the densities. The 1-19 group has 16 species. The information function is also highest in the 20-24 group.

An attempt was made to achieve the faunal composition of the 1-19 group for replicates 20-24 by removal of percents of small-sized taxa. Comparable relative abundances are best achieved by removing 100% of Epistominella subperuviana and 95% of Bolivina brevior and other significant small-sized species. Total specimen numbers for both small- and large-sized species remains higher in replicates 20-24 than in 1-19, however. Thus, analysis of species percentages and species specimen size indicates that while transportation—winnowing—of small specimens (or large specimens) into or out of the environment of deposition may be significant, it does not account for the differences between replicates 1-19 and 20-24. Therefore, either two habitats or some other mode of allocthonous enrichment or depletion rather than particle size winnowing must be invoked to account for the observed distribution.

The low numbers of species, especially with so many individuals, indicates the fauna probably lived under stressful conditions. Low amounts of available oxygen may have caused the stress.

Middle Proterozoic (1.5 Ga) Horodyskia moniliformis Yochelson and Fedonkin, the Oldest Known Tissue-Grade Colonial Eucaryote
Mikhail A. Fedonkin and Ellis L. Yochelson
29 pages, 19 figures
2002 (Date of Issue: 29 January 2002)
Number 94, Smithsonian Contributions to Paleobiology
DOI: 10.5479/si.00810266.94.1
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“Problematic bedding-plane markings” discovered by the late R.J. Horodyski from the Appekunny Formation in Glacier National Park, Montana, and dated at approximately 1.5 giga-annum (Ga), were never formally named. We are convinced the specimens are biogenic and have placed them within Linnaean nomenclature as Horodyskia moniliformis Yochelson and Fedonkin. An apt description of the locally abundant fossils is “string of beads.” On each string, beads are of nearly uniform size and spacing; proportionally, bead size and spacing remain almost constant, regardless of string length or size of individual beads. They may not be related to any other known fossil, and their position within highest levels of the taxonomic hieararchy is enigmatic. We judge they were multicellular, tissue-grade, colonial eucaryotes. Similar strings have been reported from Western Australia, but nowhere else. The general geologic setting in Montana, details of sedimentation, and taphonomy suggest the organisms were benthonic, growing upward about 1 cm through episodically deposited eolian dust. During life, specimens were stiff and relatively strong, but show no evidence of a mineralized skeleton. They lived in poorly oxygenated water with the body progressively subjected to anaerobic conditions. Their energy source is obscure; their mode of growth and several features of interpreted environment lead us to speculate that Horodyskia likely lived primarily by ingesting chemosynthetic bacteria rather than by photosynthesis. This notion should be tested by searching red, fine-grained, subaqueous arenites of approximately the same age throughout the world for additional occurrences.

Mode of Growth and Functional Morphology of Autozooids in Some Recent and Paleozoic Tubular Bryozoa
Richard S. Boardman
51 pages, 6 figures, 11 plates
1971 (Date of Issue: 23 August 1971)
Number 8, Smithsonian Contributions to Paleobiology
DOI: 10.5479/si.00810266.8.1
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Membranous structures reflecting functional organs are recognizable in a relatively few tubular Bryozoa of Paleozoic age belonging largely to the order Trepostomata. Some skeletal structures also seem to reflect functional organs in a generalized way. Thin sections, including both hard and soft parts, of several genera of Recent tubular Bryozoa of the order Cyclostomata provide a first approximation to the shape, size, and position of cuticular or membranous structures in autozooids that might be preserved under exceptional conditions in fossils. Potentially preservable cuticular or membranous structures include: (1) outward opening funnel-shaped terminal-vestibular membranes and sphincter muscle regions; (2) flask- or sac-shaped membranous sacs; and (3) the spherical-to-formless sex organs and brown bodies.

Most of the diaphragms common to trepostome autozooecia presumably formed floors for living chambers of successive functioning bodies in the degeneration-regeneration cycle. The position of some skeletal intrazooecial structures within living chambers must have been lateral to functioning organs. Mural spines that have a definite distributional pattern might represent calcified attachment points for ligaments or muscles. Skeletal cystiphragms, hemiphragms, ring septa, and autozooecial wall thickenings all seem to be lateral features which provided significant modifications to the shape and size of the autozooidal living chamber. These and other skeletal structures appear to have been developed by zooids growing with colony-wide cyclic coordination so that skeletal structures commonly display a constant relative spacing or size correlation in the growth sequence of a colony. Hemiphragms, cystoidal diaphragms, ring septa, and skeletal cystiphragms and funnel-cystiphragms in some species are perhaps more comparable in cycle with basal diaphragms of autozooecia, suggesting that their distribution might have been controlled largely by degeneration-regeneration cycles. Closely tabulated mesopores seem to provide an expression of the most frequent colony-wide cycles in many species and can be correlated one-to-one with some mural spines and skeletal cystiphragms. Perhaps these most closely spaced structures reflect an increase in length of soft parts during a single functional stage of the degeneration-regeneration cycle.

Some monticuliporid and diaphragmed trepostomes contain a second type of cystiphragm that forms small flask-shaped chambers filled with brown deposits that suggest a concentration of organic material during the life of the colony. These chambers do not preclude retractable lophophores but almost certainly the inflexible necks restrict significantly the room for passage of membranous structures. Because of this restriction and the scattered or thinly cyclic distribution of flask-shaped chambers known from only a few species, a primary food-gathering function does not seem feasible for them. Possibly, these restricted chambers had a reproductive function, conceivably comparable to the male zooids with reduced numbers of tentacles reported in a few species of cheilostome Bryozoa. Regardless of function, if the flask-shaped chambers and their inferred organs were zooids, they represent intrazooecial polymorphism, contrasting morphologically with the alternating and consistently present living chambers that presumably contained food-gathering organs. The shape, size, and position of food-gathering organs seem more likely then to be reflected by intrazooecial structures that are repeated regularly in autozooecia, such as basal diaphragms, cystiphragms, hemisepta, ring septa, and annular thickenings of zooecial walls.

Displaying 31 - 40 from the 97 total records