''Hadrianus'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

tortoise Tortoises () are reptiles of the family Testudinidae of the order Testudines (Latin: ''tortoise''). Like other turtles, tortoises have a turtle shell, shell to protect from predation and other threats. The shell in tortoises is generally hard, ...

belonging to the Testudinidae found in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

, the Yolomécatl Formation of

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

, the Alai Beds of

Kyrgyzstan Kyrgyzstan,, pronounced or the Kyrgyz Republic, is a landlocked country in Central Asia. Kyrgyzstan is bordered by Kazakhstan to the north, Uzbekistan to the west, Tajikistan to the south, and the People's Republic of China to the east. ...

and

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...

and believed to be the oldest true tortoise known. 2004 "Skeletochronology as a method of aging Oligocene ''Gopherus laticuneus'' and ''Stylemys nebrascensis'', using ''Gopherus polyphemus'' as a modern analog" Thesis, University of Florida. The genus is thought to be closely related to the genus ''

Manouria ''Manouria'' is a genus of tortoises in the family Testudinidae. The genus was erected by John Edward Gray in 1854. Species The following five species are recognized as being valid, two of which are extant, and three of which are extinct: *''Ma ...

''. The genus may have evolved in the subtropics of Asia and subsequently migrated to North America and Europe.

References

Prehistoric life of Europe Hadrianus (genus) Eocene reptiles of North America Prehistoric turtle genera Taxa named by Edward Drinker Cope Extinct turtles {{paleo-turtle-stub