''Gomphos'' 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 ...

of early

lagomorph The lagomorphs are the members of the taxonomic order Lagomorpha, of which there are two living families: the Leporidae (hares and rabbits) and the Ochotonidae (pikas). The name of the order is derived from the Ancient Greek ''lagos'' (λαγ� ...

from the early

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

of the

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

and

Mongolia Mongolia; Mongolian script: , , ; lit. "Mongol Nation" or "State of Mongolia" () is a landlocked country in East Asia, bordered by Russia to the north and China to the south. It covers an area of , with a population of just 3.3 million, ...

. Gomphos was first named in 1975 from material found in the Gashato Formation. There are currently two species in this genus: ''G. elkema'', from the Greek word ''γόμφος'' (Romanized gomphos), which means "peg", but can also be used to signify molar teeth; and ''G. shevyrevae'' was named later in honour of the lead author who named the first original genus and species of ''Gomphos elkema''. Analysis supports ''Gomphos'' as one of the earliest lagomorphs, the group that includes rabbits, hares and pikas.Asher, Robert J., Jin Meng, John R. Wible, Malcolm C. McKenna, Guillermo W. Rougier, Demberlyn Dashzeveg, and Michael J. Novacek. "Stem Lagomorpha and the antiquity of Glires." Science 307, no. 5712 (2005): 1091-1094. It is likely that lagomorphs split off from the rest of the placental mammals around the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

Palaeogene The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago ( Mya) to the beginning o ...

boundary.

Sources

* ''The Beginning of the Age of Mammals'' by Kenneth D. Rose * ''The Rise of Placental Mammals: Origins and Relationships of the Major Extant Clades'' by Kenneth D. Rose and J. David Archibald

References

External links

''Gomphos''
in the

Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms. History The Paleobiology Database (PBDB) originated in the NCEAS-funded Phanerozoic Marine Pale ...

Prehistoric placental genera Prehistoric mammals of Asia Eocene mammals Fossil taxa described in 1975 {{lagomorph-stub