Pachyrukhos

Pachyrukhos is an extinct genus of hegetotheriid notoungulate from the Early to Middle Miocene (Colhuehuapian-Friasian in the SALMA classification) of Argentina and Chile. Fossils of this genus have been found in the Collón Curá, Sarmiento and Santa Cruz Formations of Argentina and the Río Frías Formation of Chile.

Description
It was about 30 cm long and closely resembled a rabbit, with a short tail and long hind feet. Pachyrukhos was probably also able to hop, and it had a rabbit-like skull with teeth adapted for eating nuts and tough plants. The complexity of its hearing apparatus in the skull suggests that its hearing would have been very good, and that it probably had large ears. It also had large eyes, suggesting that it may have been nocturnal. These similarities are the result of convergent evolution, since, while quite unrelated to modern rabbits, Pachyrukhos filled the same ecological niche.