Telmatherium

Telmatherium is a genus of a North American brontothere. It lived during the Eocene epoch.

== Description == thumb|left|Musculature of Telmatherium (then known as Manteoceras) Known from mostly cranial material, Telmatherium is a medium-sized hornless brontothere, with a notable post-canine diastema and sub-caniniform upper incisors. The first premolar is relatively simple, and there is a small diastema between the second and third lower premolars. Molar size of Telmatherium has been compared to Palaeosyops. A great amount of variance has been found in specimens of Telmatherium via isotopic analysis, especially so compared to other brontotheres such as Palaeosyops. The zyogmatic arch is less developed than other brontothere genera, and the nasals are described as compressed and laterally decurved. The unique nasal morphology of Telmatherium has been suggested to indicate the genus is ancestral to the later horned brontotheres, though others believe there is no direct ancestral relationship between the two.