Search form

Blog Icon Facebook Icon Twitter Icon Tumblr Icon Instagram Icon Flickr Icon YouTube Icon RSS Icon Email Icon

Smithsonian Institution Scholarly Press Smithsonian Institution Libraries
Displaying 21 - 30 from the 97 total records
Previous 10 | Next 10

Ultrastructural Studies on Graptolites, 1: The Periderm and Its Derivatives in the Dendroidea and in Mastigograptus
Adam Urbanek and Kenneth M. Towe
48 pages, 2 figures, 30 plates, 2 tables
1974 (Date of Issue: 15 May 1974)
Number 20, Smithsonian Contributions to Paleobiology
DOI: 10.5479/si.00810266.20.1
Go to : Article in digital repository (repository url is stable, and repository may include .pdf of the article and additional related files)
Display: PDF Hi-Res (23,118 kb) | PDF Lo-Res (8,747 kb) | Plain Text |
Full Description (from SIRIS)

Abstract

Organic skeletons of two dendroid graptolites and an aberrant sessile graptolite (Mastigograptus sp.), all Ordovician in age, were isolated chemically from the matrix and used subsequently for ultrastructural studies with the transmission electron microscope. Peridermal material of all forms investigated proved to be unusually well preserved as far as ultrastructural features are concerned, and it reveals a variety of fabrics and patterns classified into two structural categories: fabric and tissue. Following Kozlowski (1949) the term tissue is retained for larger structural components of the periderm, defined from a morphogenetic point of view. To distinguish the fusellar and cortical tissue, directly observed structures are classified as fabrics defined by the form of their unit elements and their spatial interrelations. Fusellar, cortical, sheet, and crassal fabrics were distinguished and characterized. Fusellar and cortical fabrics are both fibrillar but differ in fibril diameter. Fibrils are branched and wavy, or straight, producing a mesh, or showing a parallel arrangement and packed into layers. Sheet fabric is an electron dense, homogenous or densely reticulated material delimiting particular layers within the cortical tissue or producing an external pellicle on the fuselli. Crassal fabric is an electron dense and featureless material found in the sheath of stolons and as a secondary deposit inside the thecae in Mastigograptus sp. A given peridermal tissue is thus composed of more than one fabric, but with a predominance of either a fusellar or cortical one.

In addition to an earlier observation (Towe and Urbanek, 1972) that cortical fibrils are collagen-like, arguments are presented in favor of the opinion that fusellar fibrils may also represent the collagen group of fibrous proteins. Frequently observed passages of a single fusellar fibril within the body of a fusellus, into a fibril of an outer lamella of the same fusellus, showing a typically cortical arrangement of the fibrils, seems to indicate the same chemical nature of the fibrous components in both fabrics. Differences in their physical organization are here ascribed to the changes in the composition of the matrix.

The unexpected presence of a cortical coating on the inner thecal walls in Dictyonema sp. is explained through delayed growth of lateral thecae in the triad and very early deposition of cortical tissue over the outer surface of the young autotheca (autocortex). This wall is later overgrown by lateral thecae to become an inner thecal wall. A common cortical envelope secreted later over the outer surface of all thecae is called the rhabdocortex. The presence of a cortical component on the inner surface of the inner thecal walls in Acanthograptus sp. suggests, that at least in some dendroids also, the soft tissues inside the thecal cavity were capable of secretion of the cortical tissue. This changes the classical scheme of cortical tissue formation as proposed by Kozlowski (1949).

The fusellar tissue in Mastigograptus sp. reveals unusual, erratic distribution of fuselli, which are present only on certain places in the thecal wall. Over large areas these are substituted by a peculiar layer of electron dense, homogenous material termed here the crassal fabric. This is interpreted as a presumed secondary resorption and subsequent substitution of the fusellum by the crassal layer. The basal disc of Mastigograptus sp. is composed of a material resembling that in cortical fabric but with fewer fibrils embedded in abundant matrix. The lower layer of the basal disc is provided with numerous filaments made of delicate fibrils. The sclerotized sheaths of stolons recognized in Acanthograptus sp. are made mainly of the crassal fabric.


Permian Brachiopods of West Texas, IV (text)
G. Arthur Cooper and Richard E. Grant
685 pages, 1 figure, 160 plates
1976 (Date of Issue: 12 February 1976)
Number 21 (text), Smithsonian Contributions to Paleobiology
DOI: 10.5479/si.00810266.21.text
Go to : Article in digital repository (repository url is stable, and repository may include .pdf of the article and additional related files)
Display: PDF Hi-Res (151,287 kb) | PDF Lo-Res (15,922 kb) | Plain Text |
Full Description (from SIRIS)

Abstract

The fourth of a six-part monograph on the Permian brachiopods from several mountain ranges in western Texas, especially the Glass Mountains of Brewster County, this volume contains descriptions of genera and species in the orders Rhynchonellida and Spiriferida. The Rhynchonellida contain 30 genera in the superfamily Rhynchonellacea and 3 genera in the superfamily Stenoscismatacea. The Spiriferida contain 2 genera of Cyrtiacea, 4 of Athyridacea, 9 of Spiriferacea, and 6 of Reticulariacea.


Permian Brachiopods of West Texas, IV (plates)
G. Arthur Cooper and Richard E. Grant
685 pages, 1 figure, 160 plates
1976 (Date of Issue: 12 February 1976)
Number 21 (plates), Smithsonian Contributions to Paleobiology
DOI: 10.5479/si.00810266.21.plates
Go to : Article in digital repository (repository url is stable, and repository may include .pdf of the article and additional related files)
Display: PDF Hi-Res (73,229 kb) | PDF Lo-Res (27,193 kb) | Plain Text |
Full Description (from SIRIS)

Abstract

The fourth of a six-part monograph on the Permian brachiopods from several mountain ranges in western Texas, especially the Glass Mountains of Brewster County, this volume contains descriptions of genera and species in the orders Rhynchonellida and Spiriferida. The Rhynchonellida contain 30 genera in the superfamily Rhynchonellacea and 3 genera in the superfamily Stenoscismatacea. The Spiriferida contain 2 genera of Cyrtiacea, 4 of Athyridacea, 9 of Spiriferacea, and 6 of Reticulariacea.


Ultrastructural Studies on Graptolites, 2: The Periderm and Its Derivatives in the Graptoloidea
Adam Urbanek and Kenneth M. Towe
48 pages, 3 figures, 24 plates, 1 table
1975 (Date of Issue: 16 May 1975)
Number 22, Smithsonian Contributions to Paleobiology
DOI: 10.5479/si.00810266.22.1
Go to : Article in digital repository (repository url is stable, and repository may include .pdf of the article and additional related files)
Display: PDF Hi-Res (22,099 kb) | PDF Lo-Res (6,753 kb) | Plain Text |
Full Description (from SIRIS)

Abstract

The ultrastructure of the organic periderm in Didymograptus sp. (Lower Ordovician), Pristiograptus dubius (Suess), and in the retiolitid Holoretiolites mancki (Münch) (both Upper Silurian), isolated by chemical treatment, has been studied with the transmission electron microscope. In the first two graptoloids, with continuous peridermal walls in the rhabdosome, the periderm is composed of the major fusellar and cortical components which are essentially the same as those recognized earlier in the dendroid graptolites (Urbanek and Towe, 1974). In addition, both graptoloids examined show important differences in the fabric ultrastructure of some homologous parts of the rhabdosome such as the nema in Didymograptus sp., the virgula in P. dubius, as well as the prosicula in both. These occurrences of sharp differences in the submicroscopic structure of homologous parts of rhabdosomes within the Graptoloidea are suggestive of rather substantial phylogenetic changes in the history of the group at the ultrastructural level.

In addition to the peridermal materials previously recognized in the dendroids, certain parts of the rhabdosomes in graptoloids are constructed of a peculiar fabric termed the virgular fabric. It has been recognized so far in the virgula of Pristiograptus dubius and in the lists of the peridemal framework (clathrium) of Holoretiolites mancki, where it is the only component of the skeleton. It is composed of layers made of lucent fibrils with a unique substructure, embedded in an electron dense and homogeneous matrix, and separated by thin layers formed by this matrix alone. The biochemical relationships of these fibrils with extant fibrous materials are uncertain but a correlation with certain collagens has been suggested.

The structural relationships of the outer cortical deposit of thecae examined in Didymograptus sp. and in Pristiograptus dubius are indicative of different modes of secretion of the cortex in both. In Didymograptus sp. the cortex is formed through an accumulation of the overlapping outer lamellae of fuselli, while in Pristiograptus dubius the layers of the cortex are laid down over the surface of the fuselli as independent units. Moreover, other observations seem to indicate that in Didymograptus sp. the cortex has been formed in a somewhat different way at certain places on the rhabdosome. There does not seem to be any single, uniform pattern of secretion of the cortex in the Graptoloidea.


Paleornithology of St. Helena Island, South Atlantic Ocean
Storrs L. Olson
49 pages, 10 figures, 6 plates, 8 tables
1975 (Date of Issue: 20 June 1975)
Number 23, Smithsonian Contributions to Paleobiology
DOI: 10.5479/si.00810266.23.1
Go to : Article in digital repository (repository url is stable, and repository may include .pdf of the article and additional related files)
Display: PDF Hi-Res (18,506 kb) | PDF Lo-Res (2,706 kb) | Plain Text |
Full Description (from SIRIS)

Abstract

The present avifauna of St. Helena is a very depauperate one, many species of birds having been extirpated since man's discovery of the island in 1502. The great extent of this extinction was confirmed by a study of over 4600 specimens of fossil and subfossil bird bones, representing 21 species, collected from rich deposits on the island. These deposits vary in age and fall roughly into three groups, the oldest of which extends well back into the Pleistocene, the youngest of which is very recent, and the third is intermediate. The deposits yielded the remains of the following species, six of which are here described as new: Procellariidae—Pterodroma rupinarum, new species, Bulweria bifax, new species, Puffinus pacificoides, new species, P. griseus, P. Iherminieri; Oceanitidae—Pelagodroma marina, Oceanodroma castro; Phaethontidae—Phaethon aethereus; Sulidae—Sula sula, S. dactylatra; Fregatidae—Fregata ariel trinitatis, F. minor; Rallidae—Atlantisia podarces, Porzana astrictocarpus; Charadriidae—Charadrius sanctaehelenae; Laridae—Larus sp., Gygis alba, Sterna fuscata; Columbidae—Dysmoropelia dekarchiskos, new genus and species; Cuculidae—Nannococcyx psix, new genus and species; Upupidae—Upupa antaios, new species. Pterodroma rupinarum and Puffinus pacificoides belong to species-groups that presently occur in the Indo-Pacific but not in the Atlantic; no gadfly-petrel of the size of Bulweria bifax is found in the Atlantic today. Puffinus griseus and Larus sp. are thought merely to have been vagrants on St. Helena. The pigeon and the hoopoe were both large and probably flightless. Differences in the composition and relative abundance of species between the deposits of different age indicate that the marine environment at St. Helena became progressively more tropical late in the Pleistocene. This resulted in great decreases in, or even extinction of, some of the species of Procellariiformes and in the appearance later in the fossil record of more purely tropical seabirds such as boobies, frigatebirds, and Sooty Terns.


Permian Brachiopods of West Texas, V
G. Arthur Cooper and Richard E. Grant
551 pages, 1 figure, 118 plates
1976 (Date of Issue: 15 October 1976)
Number 24, Smithsonian Contributions to Paleobiology
DOI: 10.5479/si.00810266.24.1
Go to : Article in digital repository (repository url is stable, and repository may include .pdf of the article and additional related files)
Display: PDF Hi-Res (180,597 kb) | PDF Lo-Res (31,338 kb) | Plain Text |
Full Description (from SIRIS)

Abstract

The fifth of a six-part monograph on the brachiopods and Permian stratigraphy of the Glass Mountains and other ranges in western Texas and adjacent areas, this volume completes the systematic and descriptive part of the monograph with a discussion of the punctate groups. The Order Rhipidomellida contains 1 genus in the superfamily Rhipidomellacea, 4 in the Enteletacea, 1 in the Rhynchoporcea, 11 in the Spiriferinacea, and 2 in the Retziacea. The greatest number of species in this volume belong to the Order Terebratulida, contained in 19 genera.


Revised Tertiary Stratigraphy and Paleontology of the Western Beaver Divide, Fremont County, Wyoming
Robert J. Emry
20 pages, 6 figures
1975 (Date of Issue: 23 October 1975)
Number 25, Smithsonian Contributions to Paleobiology
DOI: 10.5479/si.00810266.25.1
Go to : Article in digital repository (repository url is stable, and repository may include .pdf of the article and additional related files)
Display: PDF Hi-Res (14,218 kb) | PDF Lo-Res ( 918 kb) | Plain Text |
Full Description (from SIRIS)

Abstract

In the western Beaver Divide area in west-central Wyoming, a lens of coarse Tertiary volcanic conglomerate and tuff disconformably overlies Uintan rocks of the Wagon Bed Formation. The coarse volcaniclastic rocks were previously regarded as a facies of the Beaver Divide Conglomerate Member of the Chadronian White River Formation, although fossil mammals from the volcaniclastic unit are species known otherwise only from Uintan rocks. Reexamination of field relations has shown that the White River Formation disconformably overlies the volcaniclastic unit. The “lower Uinta C” temporal equivalence indicated by the fossils from the volcaniclastic unit is no longer anomalous; the underlying Wagon Bed Formation has fossil mammals indicating “Uinta B” equivalence, and the overlying White River Formation has a fairly diverse Chadronian fauna. The Uintan volcaniclastic unit is assigned to the Wiggins Formation. The Beaver Divide Conglomerate Member is restricted to conglomerate in the lower part of the White River Formation. It is composed predominantly of clasts of locally derived Precambrian crystalline rocks.


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
Go to : Article in digital repository (repository url is stable, and repository may include .pdf of the article and additional related files)
Display: PDF Hi-Res (9,824 kb) | PDF Lo-Res (1,421 kb) | Plain Text |
Full Description (from SIRIS)

Abstract

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.


Collected Papers in Avian Paleontology Honoring the 90th Birthday of Alexander Wetmore
Storrs L. Olson, editor
211 pages, 91 figures, 38 tables
1976 (Date of Issue: 21 May 1976)
Number 27, Smithsonian Contributions to Paleobiology
DOI: 10.5479/si.00810266.27.1
Go to : Article in digital repository (repository url is stable, and repository may include .pdf of the article and additional related files)
Display: PDF Hi-Res (71,673 kb) | PDF Lo-Res (10,443 kb) | Plain Text |
Full Description (from SIRIS)

Abstract

Eighteen papers covering diverse aspects of avian paleontology—from the earliest known bird to extinct species found in Indian middens—are collected here to honor the 90th birthday of Alexander Wetmore. These are preceded by an appraisal of the current state of avian paleontology and of Alexander Wetmore's influence on it, including a bibliography of his publications in this field. John H. Ostrom analyzes the hypothetical steps in the origin of flight between Archaeopteryx and modern birds. Philip D. Gingerich confirms that Ichthyornis and Hesperornis did indeed bear teeth, that the palate in Hesperornis is paleognathous, and that these Cretaceous toothed birds appear to occupy a position intermediate between dinosaurs and modern birds. Larry D. Martin and James Tate, Jr. describe the skeleton of the Cretaceous diving bird Baptornis advenus and conclude that the Baptornithidae belong in the Hesperornithiformes, but are less specialized than Hesperornis. Pierce Brodkorb describes the first known Cretaceous land bird as forming a new order possibly ancestral to the Coraciiformes and Piciformes. E. N. Kurochkin summarizes the distribution and paleoecology of the Paleogene birds of Asia, with particular emphasis on the evolution of the gruiform families Eogruidae and Ergilornithidae. Pat Vickers Rich and David J. Bohaska describe the earliest known owl from Paleocene deposits in Colorado. Alan Feduccia transfers the Eocene genus Neanis from the Passeriformes to the Piciformes and he and Larry D. Martin go on to refer this and four other genera to a new family of Piciformes, concluding that these were the dominant perching land birds of the Eocene of North America. Storrs L. Olson describes a new species of Todidae from the Oligocene of Wyoming and refers the genus Protornis from the Oligocene of Switzerland to the Momotidae, concluding that the New World Coraciiformes originated in the Old World. Charles T. Collins describes two new species of the Eo-Oligocene genus Aegialornis and presents evidence that the Aegialornithidae should be referred to the Caprimulgiformes rather than to the Apodiformes, although they might be ancestral to the swifts. In the following paper he shows that the earliest known true swifts (Apodidae) are three nominal forms from the Lower Miocene of France which prove to be but a single species of Cypseloides, a modern genus belonging to a primitive subfamily now restricted to the New World. Stuart L. Warter describes a new osprey from the Miocene of California to provide the earliest certain occurrence of the family Pandionidae and he treats functional aspects of the evolution of the wing in Pandion. Hildegarde Howard describes a new species of flightless mancalline auk, also from the Miocene of California, which is temporally and morphologically intermediate between Praemancalla lagunensis and the species of Mancalla. Robert W. Storer analyzes Pleistocene fossils of pied-billed grebes, synonymizing Podilymbus magnus Shufeldt with modern P. podiceps and describing a new species from peninsular Florida. Kenneth E. Campbell, Jr., lists 53 species of birds, including new species of Buteo and Oreopholus, from a Pleistocene deposit in southwestern Ecuador and compares this with a fauna of similar age from northwestern Peru, both of which indicate more humid conditions in the past. Oscar Arredondo summarizes aspects of the morphology, evolution, and ecology of the gigantic owls, eagles, and vultures recently discovered in Pleistocene deposits in Cuba. Joel Cracraft analyzes variation in the moas of New Zealand, reduces the number of species recognized to 13, and suggests that several “species pairs” represent examples of sexual size dimorphism. G. Victor Morejohn reports remains of the extinct flightless duck Chendytes lawi, previously known only from Pleistocene deposits, from Indian middens in northern California and concludes that the species became extinct through human agency less than 3800 years ago.


Phoca wymani and Other Tertiary Seals (Mammalia: Phocidae) Described from the Eastern Seaboard of North America
Clayton E. Ray
36 pages, 3 figures, 11 plates
1976 (Date of Issue: 14 May 1976)
Number 28, Smithsonian Contributions to Paleobiology
DOI: 10.5479/si.00810266.28.1
Go to : Article in digital repository (repository url is stable, and repository may include .pdf of the article and additional related files)
Display: PDF Hi-Res (14,496 kb) | PDF Lo-Res (2,457 kb) | Plain Text |
Full Description (from SIRIS)

Abstract

Fossil seal remains from Richmond, Virginia, first reported by Wyman in 1850, and named Phoca wymani by Leidy in 1853, have been neglected and unjustifiably regarded as cetacean by most subsequent authors. Recently recognized parts of the holotype and other material, in part recently collected in Richmond, show that the species is a monachine seal, here called Monotherium? wymani (Leidy, 1853a). It is derived from Miocene beds that are definitely older than the Yorktown Formation and probably correlative with the Calvert Formation of Maryland. Thus Monotherium? wymani is probably the oldest known monachine. Other evidence of fossil phocids in eastern North America is reviewed.


Displaying 21 - 30 from the 97 total records