Fossil Record of Lagostomus: A 10 Million Years Story

Despite being represented by a single extant species, Lagostomus maximus, the fossil record of the genus Lagostomus is extremely rich and the oldest of all living caviomorph rodents. It was recognized in the Chasicoan Stage/Age (Late Miocene) of Argentina, with younger records in Argentina, Bolivia, Uruguay, and Brazil. Many extinct species were described in the late nineteenth to early twentieth centuries, most of them based on fragmentary remains. Due to the fossorial habits of extinct vizcachas, they are very frequent in late Cenozoic continental associations, but their remains are not frequently identified to a specific level. Recent revisions have synonymized many of the named extinct species and have identified numerous fossil remains, revealing their biostratigraphic value. In this chapter, the fossil record of Lagostomus is revised, with remarks on its biostratigraphy and biogeography.