Catapleura sp.

Robert & Weems, E., 2014, Paleogene chelonians from Maryland and Virginia, PaleoBios 31 (1), pp. 1-32 : 18-21

Catapleura sp.

(Figs. 13E-I)

Specimens –CMM-V-4774, proximal costal found by Gary Grimsley; CMM-V-4775, proximal costal found by Bob Wiest.

Locality, horizon, and age –Found in the bluff immediately west of Loyola Retreat, 1.7 miles north of Popes Creek; lower part (Bed A) of the Woodstock Member of the Nanjemoy Formation; early Eocene (Ypresian), within nannoplankton zone NP12.

Description –Costal thin with a smooth surface texture, average thickness about 4–5 mm and maximum thickness 7 mm over center of rib shaft. Proximal rib neck short and stout, with an elliptical rib head twice as wide as high.

Remarks –These costals are far too large to belong to Tasbacka Nessov 1987 or Puppigerus Cope 1870 . They are quite similar to the costal elements of Catapleura and Euclastes Cope 1867 , but differ from Euclastes in being exceptionally thin. It seems likely that they pertain to the same taxon Weems (1999) called? Dollochelys sp. from

/ Figure 13. A–I. Carapace elements of Catapleura . A. Second left costal of Catapleura coatesi in dorsal view, CMM-V-4764. B–D. Fourth neural of Catapleura coatesi , CMM-V-4765. B, dorsal view; C, lateral view; D, ventral view. E. Proximal costal of

Catapleura sp. , dorsal view, CMM-V-4774. F–I. Proximal costal of Catapleura sp. , CMM-V-4775. F, proximal view; G, ventral view; H, anterior view; I, dorsal view.

the early Nanjemoy Formation (bed B of the Potapaco Member) at the Fisher/Sullivan site in Stafford County, Virginia. At neither the Fisher/Sullivan site nor at the bluffs around Popes Creek have even fragments of the highly specialized and diagnostic premaxillaries or dentaries of Euclastes been found, which argues against the presence of that genus at any of the collected Nanjemoy localities. These costal fragments could pertain to some as yet undescribed taxon, but in the absence of evidence for this they are referred for now to Catapleura , with which they are fully comparable. In any case, these specimens document the presence of a second pancheloniid turtle in addition to Puppigerus from the Woodstock Member of the Nanjemoy Formation (discussed below).