Argyrolagus is an extinct genus of South American metatherian, belonging to the order Polydolopimorpha from the Early Pliocene Monte Hermoso Formation, Patagonia, Argentina. Jumping on its hind legs, the 40 centimetres (16 in) long Argyrolagus resembled a gerbil or kultarr. 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.