Allaeochelys sp.

Robert & Weems, E., 2014, Paleogene chelonians from Maryland and Virginia, PaleoBios 31 (1), pp. 1-32 : 10

Allaeochelys sp.

( Figs. 8I–K)

Specimen —CMM-V-4779, peripheral element found by Ron Ison; CMM-V-4780, fragment of right hypoplastron found by Bob Wiest.

Locality, horizon, and age — Both specimens came from outcrops of the Piney Point Formation along the Pamunkey River in eastern Hanover County, Virginia; middle Eocene (late Lutetian to early Bartonian) .

Description —Peripheral is thick in cross-section, with pitted to vermiform sculpture on its external surfaces and a sutural border on its proximal end for attachment to a costal element. The hypoplastron is strongly constricted in its medial region and also has pitted to vermiform sculpture on its external surface. Neither element shows any evidence of sulci marking scale boundaries.

Remarks —The pitted to vermiform sculpture on these elements and the absence of evidence for sulci show them to pertain to Trionychia, but the presence of peripherals precludes assignment to the family Trionychidae Gray 1825 . Therefore, this material pertains to the family Carettochelyidae . Only three genera of carettochelyids are known from North America: Anosteira Leidy 1871 , Pseudanosteira Clark 1932 , and Allaeochelys . The large size and the details of the sculpture both preclude assigning this material to Anosteira or Pseudanosteira , but in both regards it is fully comparable to Allaeochelys . Only one other occurrence of Allaeochelys has been reported from North America ( Westgate 1989). It is interesting that the material was found in a middle Eocene estuarine setting in Texas that was similar to the shallow marine setting of the Piney Point Formation in Virginia. In contrast, Anosteira and Pseudanosteira seem to be restricted to nonmarine deposits of Eocene age in western North America and China ( Hay 1908, Tong et al. 2010). Allaeochelys apparently did not survive in North America beyond the middle Eocene.