Section of Invertebrate Paleontology

Pittsburgh, PA, United States

Section of Invertebrate Paleontology

Pittsburgh, PA, United States

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Lucas S.G.,Section of Vertebrate Paleontology | Kollar A.D.,Section of Invertebrate Paleontology | Berman D.S.,Section of Vertebrate Paleontology | Henrici A.C.,Section of Vertebrate Paleontology
Annals of Carnegie Museum | Year: 2016

The Lower Permian Dunkard Group has yielded a sparse record of tetrapod footprints that are assigned to the ichnogenera Dimetropus Romer and Price, 1940, Dromopus Marsh, 1894, and Limnopus Marsh, 1894. We report two new occurrences of Dimetropus that significantly extend its stratigraphic range in the Dunkard Group to the Washington and Greene formations. The only previous Dunkard record of Dimetropus is of D. berea (Tilton, 1931), the type ichnospecies of the ichnogenus, from the Waynesburg Formation of West Virginia. Dimetropus (eupelycosaur), Dromopus (araeoscelid), and Limnopus (large temnospondyl) footprints are present in many Late Pennsylvanian-Early Permian footprint assemblages. The Dunkard footprints of Dimetropus reported here are very large for the ichnogenus, so it seems likely they were made by one of the relatively large eupelycosaurs, Dimetrodon Cope, 1877, Ophiacodon Marsh, 1878, or Ctenospondylus Romer, 1936, known from Dunkard Group body fossils.

Berman D.S.,Section of Vertebrate Paleontology | Henrici A.C.,Section of Vertebrate Paleontology | Brezinski D.K.,Section of Invertebrate Paleontology | Kollar A.D.,Section of Invertebrate Paleontology
Annals of Carnegie Museum | Year: 2010

Fedexia striegeli, a new genus and species of trematopid temnospondyl amphibian, is described on the basis of a single specimen that includes the greater portion of the skull and articulated portions of both mandibles and the atlas-axis complex, The holotype was collected from Upper Pennsylvanianearly Virgilian strata assignable to the lower part of the Casselman Formation of the Conemaugh Group in western Pennsylvania. This is not only the first trematopid to be reported from the State of Pennsylvania, but also, in addition to Actiobates Eaton, 1973, and Anconastes Berman et al., 1987, only the third reported Late Pennsylvanian member of the family that otherwise has a greater Early Permian representation. A cladistic analysis of the Dissorophoidea was performed utilizing primarily cranial characters and only members of Amphibamidae, Trematopidae, and Dissorophidae that are well represented in this field of inquiry. This includes Ecolsonia Vaughn, 1969, whose relationships to the latter two families have been controversial. The resultant cladogram depicts: 1) Fedexia to be nested within a monophyletic Trematopidae as the sister taxon to the terminal dichotomy of Anconastes and Tambachia Sumida et al., 1998; 2) Trematopidae and Dissorophidae as forming monophyletic sister clades; and 3) Ecolsonia, Dissorophus Cope, 1895, and Broiliellus Williston, 1914, as forming an unresolved, terminal trichotomy within the dissorophid clade. Fedexia is representative of a wide variety of Late Pennsylvanian, medium-to-large amphibian and amniote tetrapods that record the earliest occurrence of vertebrates adapted to a terrestrial existence in North America. It is hypothesized that this biotic event was in response to the final stage of a long-term, global climatic trend toward drier conditions during the Pennsylvanian from perhumid to humid during the Early and Middle Pennsylvanian to dry subhumid or semiarid in the latest Virgilian. The lattermost climatic stage, which was also coincident with a marked retreat of the southern polar hemisphere glaciers during the late Paleozoic Ice Age, was followed by a strong and progressive reversal of the climate and an advance of the southern hemisphere glaciers to conditions characteristic of the earlier Pennsylvanian. Climatic changes during the Pennsylvanian are chronicled not only by major changes in rock types and associated lithologies, but also by a shift in the biology of the vertebrates they preserve. Middle Pennsylvanian vertebrates are characterized by large, diverse assemblages of predominantly small, aquatic amphibians and fish preserved in black shales and cannel coals associated with coal-forming and sapropelic fluvial sediments that developed in permanently wet, abandoned river channels. In contrast, the terrestrially adapted vertebrates of the MissourianVirgilian Pennsylvanian are typically preserved in thin deposits of freshwater limestone or their closely associated paleosols that are interpreted as representing seasonally dry lake deposits. Yet, aquatic amphibians continue to be a major constituent of Late Pennsylvanian vertebrate assemblages.

Carter J.L.,Section of Invertebrate Paleontology | Brezinski D.K.,Section of Invertebrate Paleontology | Kollar A.D.,Section of Invertebrate Paleontology | Dutro Jr. J.T.,Smithsonian Institution
Annals of Carnegie Museum | Year: 2014

Forty-six species, assignable to 36 brachiopod genera, are recognized, described, and illustrated from the Lower Mississippian Redwall Limestone of northern Arizona. Seven new species are recognized, four of which are named. Named species are: Spinocarinifera (Seminucella) costatula, new species; Magnumbonella ampla, new species; Setigerites gutschicki, new species; and Spirifer redwallensis , new species. The remaining three newly recognized species remain in open nomenclature because study material was too poorly preserved to justify naming. The majority of brachiopod species studied were recovered from the Thunder Springs and Mooney Falls members near the middle of the formation. The basal Whitmore Wash Member and uppermost Horseshoe Mesa Member contain only sparse and poorly preserved brachiopod material. The spotty stratigraphic distribution of collections, which were recovered from largely geographically disparate locations, resulted in the creation of a stratigraphic range chart that exhibits no recognizable segregation into any potential brachiopod zones. Many of the Redwall Limestone's brachiopod species are known from contemporaneous formations elsewhere in the Cordillera or central United States. Biostratigraphically key species such as Marginatia fernglenensis (Weller, 1909), Marginatia burlingtonensis (Hall, 1858), Stegacanthia bowsheri Muir-Wood and Cooper, 1960, Fernglenia vernonensis (Swallow, 1860), Voiseyella novamexicana (Miller, 1881), and Punctospirifer subtexta (White, 1862), indicate that much of the Thunder Springs and Mooney Falls members is correlative with latest Kinderhookian (late Tournaisian) through latest Osagean (early Viséan) formations of the American Midcontinent. These correlations indicate that the Redwall Limestone is temporally equivalent to the Fern Glen-Burlington formations of the central United States. These correlations are consistent with other Redwall forms that are biostratigraphially useful, such as foraminifers.

Harper J.A.,Section of Invertebrate Paleontology
Journal of Paleontology | Year: 2016

Three genera of gastropods described from the Lower Devonian Rockhouse Formation of Hardin County, Tennessee, currently are considered to be junior subjective synonyms of Platyceras (Visitator) Perner, 1911. Evaluation of the type specimens of these genera as well as types of two other gastropods from the same formation reveals the following: Platyostoma quadrangulare (Dunbar, 1920) is the only platyceratid gastropod among them; Saffordella tennessensis Dunbar, 1920 has a selenizone above midwhorl so it is an eotomarioidean belonging to the Gosseletinidae; Aulopea nelsoni Dunbar, 1920 and the lectotype of Distemnostoma princeps Dunbar, 1920 each has a broad subsutural sinus on the upper whorl surface similar to the Omphalotrochidae, as well as a basal sinus similar to certain primitive caenogastropods, so their systematic position is uncertain; I consider Holopea planidorsata Dunbar, 1920 to be a juvenile specimen of D. princeps; the fragmentary paralectotype of D. princeps possibly represents a gerontic form of Distemnostoma curtum Dunbar, 1920, which possesses a well-developed selenizone on an upwardly projecting shoulder at the edge of the upper whorl surface. Because D. curtum appears to be unrelated to D. princeps, the genotype of Distemnostoma, I propose the new generic name Omocordella for D. curtum. The new family Micromphalidae is erected to include Ordovician Slehoferia Rohr and Fryda, 2001, lower Carboniferous Micromphalus Knight, 1945, and Omocordella n. gen. © 2016, The Paleontological Society.

Acanthospondylus pennsylvanicus, new genus and species, is described and illustrated on the basis of a single specimen from the Conemaugh Group (Late Pennsylvanian) of western Pennsylvania. Distribution and morphology of ossicles similar to those of Eospondylus primigenius Stürtz, 1886, from the Early Devonian of Germany, including the absence of radial shields, dorsal and ventral arm plates, and the relatively wide separation of laterals over the ambulacral groove, indicates that Acanthospondylus belongs to the family Eospondylidae (Oegophiurida, Zeugophiurina) along with Eospondylus Gregory, 1897, and Kentrospondylus Lehmann, 1957. This extends the range of Eospondylidae from Early Devonian (Siegenian and Emsian) to Late Pennsylvanian (Early Kasimovian [Missourian]).

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