Hadrianus is an extinctgenus of tortoise belonging to the Testudinidae[1] found in the United States, the Yolomécatl Formation of Mexico, the Alai Beds of Kyrgyzstan and Spain[citation needed] and believed to be the oldest true tortoise known.[3] The genus is thought to be closely related to the genus Manouria.[3] The genus may have evolved in the subtropics of Asia and subsequently migrated to North America and Europe.[3] Evangelos Vlachos (2018) reassessed the North American species attributed to the genus, and determined only two as accepted namely H. corsoni & H. majusculus. The remaining species were identified as either junior synonyms, moved to other genera or considered nomen dubium do to incomplete fossils.[4]
Taxonomy
Hadrianus corsoni(Leidy, 1871)
Synonyms Emys carteriLeidy, 1871; Testudo hadrianaCope, 1871; Hadrianus quadratusCope, 1871; Hadrianus octonariaCope, 1871; Hadrianus tumidusHay 1908; Hadrianus robustusGilmore, 1915; Hadrianus utahensisGilmore, 1915; Geochelone gilmoreiAuffenberg, 1974
^E. D. Cope. 1872. Second account of new Vertebrata from the Bridger Eocene. Proceedings of the American Philosophical Society (separate) 1-3
^ abcEhret, Dana Joseph 2004 "Skeletochronology as a method of aging Oligocene Gopherus laticuneus and Stylemys nebrascensis, using Gopherus polyphemus as a modern analog" Thesis, University of Florida.
