Interatheriidae
Interatheriidae is an extinct family of notoungulate mammals from South America. Interatheriids are known from the Late Paleocene or Eocene to the Late Miocene. These animals were principally small-sized, occupying a habitat like hares, marmots and vizcachas. The majority were very small, like rodents. This was a group that lasted a long time, from the Paleocene to the last of the Miocene.
Interatheriidae is one of the mammal groups that best represent the fauna from the Santa Cruz Formation. Particularly Protypotherium with three species is characteristic of the formation: Protypotherium australe, P. praerutilum and P. attenuatum. Another well-known genus is Interatherium, particularly well represented by I. robustum.
