Rhynchotherium was first described in 1868 on the basis of a lower jaw from the Miocene of
Tlaxcala,
Mexico. Later, the type species epithet
R. tlascalae was erected for the jaw by
Henry Fairfield Osborn 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, 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. which it did.
Misassigned species •
Mastodon shepardi Leidy, 1871 •
Mastodon euhypodon Cope, 1884 - likely a species of
Gomphotherium •
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) == Life history ==