Argyrolagus is an extinct genus of South American marsupial

Marsupial

Marsupials are an infraclass of mammals, characterized by giving birth to relatively undeveloped young. Close to 70% of the 334 extant species occur in Australia, New Guinea, and nearby islands, with the remaining 100 found in the Americas, primarily in South America, but with thirteen in Central...

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Jumping on its hind legs, the 40 centimetres (15.7 in) long Argyrolagus resembled a gerbil

Gerbil

A gerbil is a small mammal of the order Rodentia. Once known simply as "desert rats", the gerbil subfamily includes about 110 species of African, Indian, and Asian rodents, including sand rats and jirds, all of which are adapted to arid habitats...

 or kultarr

Kultarr

The Kultarr , also known as the Jerboa-marsupial, the Jerboa Pouched-mouse, the Wuhl-wuhl or the Pitchi-pitchi, is a member of the Dasyuromorphia order. It is the only species in the Antechinomys genus...

. It had a long tail for balance, and a narrow head with a pointed snout. Judging from its huge eyes, Argyrolagus was nocturnal. The form of its teeth suggest that it would have fed on desert plants.