Thoatherium (meaning "active swift-beast") is an extinct genus of litoptern mammals from the Early Miocene of Argentina. Fossils of the genus have been found in the Santa Cruz Formation in Argentina.[1]

Thoatherium
Temporal range: Early Miocene (Santacrucian)
~17.5–16.3 Ma
1901 T. minusculum skeletal illustration
1913 T. minusculum illustration, by Charles R. Knight.
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Litopterna
Family: Proterotheriidae
Subfamily: Proterotheriinae
Genus: Thoatherium
Ameghino 1887
Type species
Thoatherium minusculum
Ameghino, 1887
Species
  • T. bilobatum Ameghino 1904
  • T. karaikense Ameghino 1904
  • T. minusculum Ameghino 1887
  • T. rhabdodon Ameghino 1894
  • T. velatum Ameghino 1904
Synonyms
Genus synonymy
  • Oreomeryx Mercerat, 1891
  • Rhagodon Ameghino, 1891
  • Diaphragmodon Mercerat, 1893
T. minisculum
  • Proterotherium cavum
    Ameghino, 1887
  • Rhagodon gracilis
    Ameghino, 1891
  • Thoatherium crepidatum
    Ameghino, 1891
  • Anisolophus burmeisteri
    Mercerat, 1891
  • Oreomeryx proprius
    Mercerat, 1891
  • Oreomyx superbus
    Mercerat, 1891
  • Diaphragmodon cavum
    (Ameghino, 1887) Mercerat, 1893
  • Diaphragmodon burmeisteri
    (Mercerat, 1891) Mercerat, 1893

Description

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T. minusculum (=T. crepidatum) skull cast. At the AMNH.

With a length of 70 centimetres (2.3 ft), the gazelle-like Thoatherium was a small representative of the order Litopterna. Judging from its long legs, it was a fast runner. Thoatherium had remarkably reduced toes; only one horse-like hoof remained. Thoatherium even lacked splint bones, which are remnants of the second and fourth toe found in modern horses. Judging from its generalised, brachydont teeth, Thoatherium fed on soft leaves rather than on tough grasses.[2][3]

 
T. minisculum right foot. Note the presence of only a single toe.

References

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  1. ^ Thoatherium at Fossilworks.org
  2. ^ Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 247. ISBN 1-84028-152-9.
  3. ^ Darin A. Croft, Horned Armadillos and Rafting Monkeys: The Fascinating Fossil Mammals of South America, Indiana University Press, 29/08/2016