Rastodon

Rastodon is an extinct genus of dicynodont. Uniquely among dicynodonts, its tusks curve forward. The type and only species is R. procurvidens.

Etymology
Rastodon is derived from the Rio do Rasto Formation, where its remains were found, and the Greek word for "tooth". The species name, R. procurvidens, means "curved forward tooth" and describes its uniquely shaped teeth.

Provenance
Only a single specimen of Rastodon has been discovered so far. It comes from Guadalupian deposits found at an outcrop of the Rio do Rasto Formation at the Boqueirão Farm, in the municipality of São Gabriel, Rio Grande do Sul, Brazil. .

Description
Rastodon is a fairly typical dicynodont. It bore a beaked head with a single pair of tusks and a keratin-covered nasal boss. However, it does possess several distinctive traits, of which its anteriorly-curved tusks are the most distinctive. Furthermore, its skull is relatively long and shallow compared to its close relatives. Its tusks contacted the lower jaw during propalinal mastication.

Classification
Rastodon has been recovered as the basalmost bidentalian dicynodont. However, the phylogenetic position of Rastodon is contentious, for it has also been recovered as the basalmost emydopoid dicynodont.