Temporal range: Late Cretaceous, 70–68 Ma
Holotype vertebra ANSP 9225 seen from three different angles
Scientific classification edit
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Suborder: Cryptodira
Family: Protostegidae
Genus: Pneumatoarthrus
Cope, 1870
P. peloreus
Binomial name
Pneumatoarthrus peloreus
Cope, 1870

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]


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]


  1. ^ a b c Leidy, 1865. Memoir on the extinct reptiles of the Cretaceous formations of the United States. Smithsonian Contributions to Knowledge. 14(6), 135 pp.
  2. ^ a b c Cope, 1870. Observations on the Reptilia of the Triassic formations of the Atlantic region of the United States. Proceedings of the American Philosophical Society. 11, 444-446.
  3. ^ Cope, 1872. A description of the genus Protostega, a form of extinct Testudinata. Proceedings of the American Philosophical Society. 12, 422-433.
  4. ^ Cope, 1875. The Vertebrata of the Cretaceous formations of the West. Report of the United States Geological Survey of the Territories. 2, 303 pp.
  5. ^ "Non-theropods".
  6. ^ Baird, D., 1979. Pneumatoarthrus Cope, 1870, not a dinosaur but a sea-turtle. Proceedings of the Academy of Natural Sciences, Philadelphia, 129(4):71-81.