Figure 9. The fused dentaries of Euclastes sp. from the upper Eocene of South Carolina (CCNHM 552) in (1) dorsal, (2) ventral, (3) lateral, and (4) posterior views.
Figure 10. Comparison of the lower jaws of Erquelinnesia, Euclastes, and Pacifichelys. Erquelinnesia after Zangerl, 1971; Euclastes after Hirayama and Tong, 2003; Pacifichelys after Lynch and Parham, 2003.
dwindled until its extinction at or near the end of the Eocene. Its extinction likely was related to the dramatic earliest Oligocene cooling event that caused widespread extinctions and transformed marine vertebrate communities worldwide (e.g., Prothero et al., 2003).
The phylogeny of Upper Cretaceous and Cenozoic pancheloniid sea turtles
Pancheloniid sea turtle skulls and associated carapaces and plastra are well represented at a few stratigraphic levels within a few
