Quaternary Argentina

meteorite discovered in the province of Chaco, Argentina

Mesotherium ("middle beast") is an extinct genus of mesotheriid, a long-lasting family of superficially rodent-like, burrowing notoungulates from South America. It is one of the youngest notoungulates, spanning the Early-Middle Pleistocene, and is the last known member of Typotheria. It was first named by Étienne Serres in 1857, though initially lacked a type species. Another genus name Typotherium, was put forward by Auguste Bravard, and three species were included: however, the name Typotherium was not applied to any particular specimens, and is thus invalid. A type species for Mesotherium,