Pneumatoarthrus

Pneumatoarthrus is an extinct genus of sea turtle known from the Late Cretaceous (early Maastrichtian) Mount Laurel Formation of Monmouth County, New Jersey.^[1][2] Only a single species, P. peloreus, is known.^[1][2]

Pneumatoarthrus Temporal range: Late Cretaceous, 70–68 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Holotype vertebra ANSP 9225 seen from three different angles
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Testudines
Suborder:	Cryptodira
Family:	†Protostegidae
Genus:	†Pneumatoarthrus Cope, 1870
Species:	†P. peloreus
Binomial name
†Pneumatoarthrus peloreus Cope, 1870

Taxonomy

The holotype of Pneumatoarthrus, ANSP 9225, was originally identified as a sacrum belonging to Hadrosaurus by Joseph Leidy in an 1865 monograph on Cretaceous reptiles from the US.^[1] Edward Drinker Cope later identified it belonging to a dinosaur more closely related to Anchisaurus, Efraasia, and Clepsysaurus than to Dryptosaurus and Ornithopsis,^[2] and in his 1872 description of the sea turtle Protostega he decided that Pneumatoarthrus was likely a sea turtle as well, which he reiterated in his 1875 monograph on Cretaceous vertebrate fossils from the Western Interior.^[3][4] Later authors overlooked Cope's 1875 monograph and considered it either a theropod or a hadrosaur (Huene 1932 considered Pneumatoarthrus the sacral vertebrae of Dryptosaurus).^[5] Baird (1979) confirmed the protostegid identification of Pneumatoarthrus by Cope (1872, 1875) based on examination of ANSP 9225.^[6]