Paleogene chelonians from Maryland and Virginia

Abstract

Author(s): Weems, Robert E. | Abstract: Fossil remains of 22 kinds of Paleogene turtles have been recovered in Maryland and Virginia from the early Paleocene Brightseat Formation (four taxa), late Paleocene Aquia Formation (nine taxa), early Eocene Nanjemoy Formation (five taxa), middle Eocene Piney Point Formation (one taxon), and mid-Oligocene Old Church Formation (three taxa). Twelve taxa are clearly marine forms, of which ten are pancheloniids (Ashleychelys palmeri, Carolinochelys wilsoni, Catapleura coatesi, Catapleura sp., Euclastes roundsi, E. wielandi, ?Lophochelys sp., Procolpochelys charlestonensis, Puppigerus camperi, and Tasbacka ruhoffi), and two are dermochelyids (Eosphargis insularis and cf. Eosphargis gigas). Eight taxa represent fluvial or terrestrial forms (Adocus sp., Judithemys kranzi n. sp., Planetochelys savoiei, cf. “Trionyx” halophilus, “Trionyx” pennatus, “Kinosternoid B,” Bothremydinae gen. et sp. indet., and Bothremydidae gen. et sp. indet.), and two taxa (Aspideretoides virginianus and Allaeochelys sp.) are trionychian turtles that probably frequented estuarine and nearshore marine environments. In Maryland and Virginia, turtle diversity superficially appears to decline throughout the Paleogene, but this probably is due to an upward bias in the local stratigraphic column toward more open marine environments that have preserved very few remains of riverine or terrestrial turtles.