Pennsylvanian bairdiidae (Ostracoda) from the Appalachian basin

Abstract

Bairdiid ostracodes are commonly present in the Pennsylvanian marine zones in the Appalachian basin. Thirty-one taxa are recognized representing the genera Bairdia McCoy, 1844; Orthobairdia Sohn, 1960; Cryptobairdia Sohn, 1960; Rectobairdia Sohn, 1960; Bairdiolites Croneis and Gale, 1939; and Bairdiacypris Bradfield, 1935. Two questionable bairdiid genera, Entmema new genus and Hastacypris Croneis and Gutke, 1939, are included. Seven new taxa, Bairdia cuspidis, Rectobairdia absidata, R. apiculata, R. levis, R. sohni, Entmena distenta, and Hastacypris acutula, are described. Fabalicypris Cooper, 1946, is considered a junior synonym of Bairdiacypris Bradfield, 1935.The diversity of bairdiids is significantly lower in the Appalachian basin than in the Eastern Interior and Western Interior basins.

Paleogeographical and paleoenvironmental significance of ostracodes from the Pennsylvanian Nagaiwa Formation, northeast Japan

“…Pseudobythocypris asiatica n. sp. is similar to P. kellettae (Cordell, 1952) from the Pennsylvanian Bonner Spring Formation and the Canville Limestone from Missouri, USA, in its narrowly arched anterior margin, but it differs in its backwardly located highest point from the anterior end, longest point at mid-height, and a more inflated outline from dorsal view. This species is also similar to P. parallela (Knight, 1928b) of Glebovskaya (1939) from the Pennsylvanian-Permian of Vyarta, northern Ural, Russia, in its straight ventral margin, but it differs in that it has a narrowly arched posterior margin, is longest at mid-height, and has a more acutely arched dorsal margin.…”

“…phaseoella (Stover, 1956) from the Middle Devonian Windom Shale Member of the Moscow Formation from western New York, USA, in its antero-ventrally truncated anterior margin, but it differs in that it has a more inflated lateral outline, a widely arched dorsal margin, and bullet-shaped outline from the dorsal view. This species is also similar to Pseudobythocypris kellettae (Cordell, 1952) from the Pennsylvanian Galesburg Shale from Missouri, USA, in its overlapped left valve to right valve at the ventral margin, but it differs in that it has a shorter anterior margin, a protruded posterior margin at two-thirds height from venter, and a bullet-shaped outline from the dorsal view. Pseudobythocypris siveteri n. sp.…”

“…Pseudobythocypris zipangu n. sp. is also similar to Pseudobythocypris oblongata (Cordell, 1952) from the Pennsylvanian Muncie Creek Shale from Missouri, USA, in its bean-shaped lateral outline, but differs in that it has a sinuate ventral margin, a widely arched postero-ventral margin, and no overlap between left valve and right valve along the dorsal area. Pseudobythocypris zipangu n. sp.…”

“…is similar to P . kellettae (Cordell, 1952) from the Pennsylvanian Bonner Spring Formation and the Canville Limestone from Missouri, USA, in its narrowly arched anterior margin, but it differs in its backwardly located highest point from the anterior end, longest point at mid-height, and a more inflated outline from dorsal view. This species is also similar to P .…”

Rhaetian (Late Triassic) ostracods (Crustacea, Ostracoda) from the offshore prolongation of the North Dobrogean Orogen into the Romanian Black Sea shelf

“…In subsequent years, the validity of Fabalicypris has been discussed, leading to different schools of thought. The first one considers that the characters differentiating Bairdiacypris and Fabalicypris are highly variable and that Fabalicypris is a junior synonym of Bairdiacypris (e.g., Sohn 1983;Hoare et al 1999). The second school of thought considers Fabalicypris as a subgenus of Bairdiacypris, described as "with overall carapace morphology of Bairdiacypris, but bairdiid shape more or less obscured; ventral overlap decreasing abruptly in anterior third to form offset or step-like process" (Becker 2001).…”