''Rhynchotherium'' is an extinct genus of

proboscidea The Proboscidea (; , ) are a taxonomic order of afrotherian mammals containing one living family ( Elephantidae) and several extinct families. First described by J. Illiger in 1811, it encompasses the elephants and their close relatives. Fr ...

endemic to North America and

Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...

during the

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" ...

through

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Ma, living for approximately . This

gomphothere Gomphotheres are any members of the diverse, extinct taxonomic family Gomphotheriidae. Gomphotheres were elephant-like proboscideans, but do not belong to the family Elephantidae. They were widespread across Afro-Eurasia and North America dur ...

had two

tusk Tusks are elongated, continuously growing front teeth that protrude well beyond the mouth of certain mammal species. They are most commonly canine teeth, as with pigs and walruses, or, in the case of elephants, elongated incisors. Tusks share ...

s and may have evolved from ''

Gomphotherium ''Gomphotherium'' (; "welded beast") is an extinct genus of proboscids from the Neogene and early Pleistocene of Eurasia, Africa, North America and Asia. As of 2021, two species, ''G. annectens'' and possibly ''G. subtapiroideum'', are also kn ...

''.

Taxonomy

''Rhynchotherium'' was first described in 1868 on the basis of a lower jaw from the Miocene of

Tlaxcala Tlaxcala (; , ; from nah, Tlaxcallān ), officially the Free and Sovereign State of Tlaxcala ( es, Estado Libre y Soberano de Tlaxcala), is one of the 32 states which comprise the Federal Entities of Mexico. It is divided into 60 municipaliti ...

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 Guate ...

. Later, the type species epithet ''R. tlascalae'' was erected for the jaw by

Henry Fairfield Osborn Henry Fairfield Osborn, Sr. (August 8, 1857 – November 6, 1935) was an American paleontologist, geologist and eugenics advocate. He was the president of the American Museum of Natural History for 25 years and a cofounder of the American E ...

in 1918. In 1921, a gomphothere skull from the Mt. Eden area of southern California was described as a subspecies of ''Trilophodon shepardi'' (a now-defunct combination for ''Mastodon shepardi''), ''T. s. edensis'', but was subsequently reassigned to ''Rhynchotherium''. Other species subsequently assigned to ''Rhynchotherium'' included ''R. falconeri'', ''R. paredensis'', ''R. browni'', and ''R. simpsoni''. It was the closest relative to ''

Cuvieronius ''Cuvieronius'' is an extinct New World genus of gomphothere, named after the French naturalist Georges Cuvier. Alive, specimens typically stood about tall at the shoulder, weighed about and would have superficially resembled a modern elephant ...

'', and may be ancestral to it. Lucas and Morgan (2008) reviewed the taxonomy of ''Rhynchotherium'' and concluded that only ''R. edensis'', ''R. falconeri'', ''R. paredensis'', ''R. browni'', and ''R. simpsoni'' could be confidently referred to ''Rhynchotherium''. Because the genotype of ''Rhynchotherium'' is referable to ''Gomphotherium'', the ICZN was petitioned to conserve the genus by designating ''R. falconeri'' as the type species, which it did. Rhynchotherium falconeri

Misassigned species

* ''Mastodon shepardi'' Leidy, 1871 * ''Mastodon euhypodon'' Cope, 1884 - likely a species of ''

''LUCAS, S.G. & MORGAN, G.S., 2008. Taxonomy of Rhynchotherium (Mammalia, Proboscidea) from the Miocene-Pliocene of North America.- New Mex. Mus. Nat. Hist. Sci. Bull. 44: 71-87. * ''Tetrabelodon brevidens'' Cope, 1889 * ''Dibelodon praecursor'' Cope, 1893 * ''Rhynchotherium rectidens'' Osborn, 1923 * ''Aybelodon hondurensis'' Frick, 1933 * ''Blickotherium blicki'' Frick, 1933 * ''Rhynchotherium anguirivale'' Osborn, 1936 Phylogenetic position according to Mothé et al. (2016)

References

Gomphotheres Miocene proboscideans Pliocene proboscideans Neogene mammals of North America Prehistoric placental genera Fossil taxa described in 1868 {{paleo-proboscidean-stub