This genus is only known from very partial remains. From the comparison with its relatives Adinotherium and Nesodon, it is supposed that Adinotherium was an herbivorous animal the size of a sheep, with an elongated body and rather short legs ; it was probably more slender-built than the two latter forms. The legs, in particular, had more delicate and slender bones than those of Adinotherium and Nesodon. Proadinotherium was characterized by its teeth with a lower crown, less hypsodont than those of Adinotherium, but evocating more derived toxodontids. Its dentition was complete with a complex structure, and the development of a crest on the molars.
Classification
Proadinotherium is considered to be the most basal and oldest member of the Toxodontidae, the most specialized group of the notoungulates, which included the well known Pleistocene genus Toxodon, as well as a number of Miocene and Pliocene forms.
Florentino Ameghino (1894). Sur les oiseaux fossiles de Patagonie; et la faune mammalogique des couches à Pyrotherium. Vol. 15. Boletin del Instituto Geographico Argentino. pp. 501–660.
F. Ameghino. 1897. Mammiféres crétacés de l’Argentine (Deuxième contribution à la connaissance de la fauna mammalogique de couches à Pyrotherium). Boletin Instituto Geografico Argentino 18(4–9):406-521
F. Ameghino. 1902. Première contribution à la connaissance de la fauna mammalogique des couches à Colpodon. Boletin de la Academia Nacional de Ciencias de Córdoba 17:71-141