Pachyrukhos

Pachyrukhos is an extinct genus of mammals from the Late Oligocene to Middle Miocene (Santacrucian-Friasian in the SALMA classification) of Argentina (Collón Curá, Sarmiento and Santa Cruz Formations) and Chile (Río Frías Formation), South America. 

Description 
It was about  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. 

References 

Category:Notoungulates
Category:Oligocene mammals of South America
Category:Miocene mammals of South America
Category:Friasian
Category:Santacrucian
Category:Neogene Argentina
Category:Fossils of Argentina
Category:Neogene Chile
Category:Fossils of Chile
Category:Fossil taxa described in 1885
Category:Taxa named by Florentino Ameghino