Rhynchippus
Rhynchippus ("Snout Horse") is an extinct genus of notoungulate mammals from the Late Oligocene (Deseadan in the SALMA classification) of South America. The genus was first described by Florentino Ameghino in 1897 and the type species is R. equinus, with lectotype MACN A 52–31. Fossils of Rhynchippus have been found in the Agua de la Piedra and Sarmiento Formations of Argentina, the Salla and Petaca Formations of Bolivia, the Tremembé Formation of Brazil, and the Moquegua Formation of Peru. Description Rhynchippus was about in length and weighed up to , with a deep body and three clawed toes on each foot. Although its teeth were extremely similar to those of horses or rhinos, Rhynchippus was actually a relative of Toxodon, having developed teeth suitable for grazing through convergent evolution. Unlike its relatives, Rhynchippus had no large tusks; they were the same size and shape as the incisors. Enamel on the molars allowed it to chew tough food. The genus shows similarities with Mendozahippus, Eurygenium and Pascualihippus. In 2016, a well-preserved specimen of R. equinus was described by Martínez et al. from the Sarmiento Formation in central Patagonia. The extraordinary preservation of the specimen allowed the researchers to appreciate the three