Osteopygis

{{Short description|Extinct genus of turtles}}

{{Automatic taxobox

| fossil_range = Late Cretaceous – Eocene, {{fossilrange|70.6|48.6}}

| image = The American journal of science (1904) (18152226245).jpg

| image_caption = Osteopygis emarginatus carapace

| taxon = Osteopygis

| authority = Cope, 1868

| type_species = Osteopygis emarginatus

| type_species_authority = Cope, 1868

| subdivision_ranks = Species

| subdivision =

• O. emarginatus Cope, 1868
• O. backmani Russell, 1934
• O. kranzi Weems, 2014
• O. russelli Brinkman, 2015

| subdivision_ref = {{cite journal|author1=Gentry, A.D.|author2=Kiernan, C.R.|author3=Parham, J.F.|year=2022|title=A large non-marine turtle from the Upper Cretaceous of Alabama and a review of North American "Macrobaenids"|journal=The Anatomical Record|doi=10.1002/ar.25054}}

}}

Osteopygis is a genus of extinct turtle. Osteopygis, as traditionally seen, is a chimera: the postcrania (including the holotype) belong to a non-marine stem-cryptodire, whilst the crania belong to sea turtles. In 2005, the referred material was split between two taxa: the postcrania remained in Osteopygis, while the crania were reassigned to Euclastes wielandi.[https://www.researchgate.net/publication/232696451_A_reassessment_of_the_referral_of_sea_turtle_skulls_to_the_genus_Osteopygis_Late_Cretaceous_New_Jersey_USA/link/0deec52015ed8493ba000000/download A reassessment of the referral of sea turtle skulls to the genus Osteopygis (Late Cretaceous, New Jersey, USA)]