Meridiolestida

Necrolestes (from Ancient Greek νεκρός (necrós), meaning "dead", and λῃστής (lēistḗs), meaning "robber") is an extinct genus of mammals, which lived during the Early Miocene in what is now Argentine Patagonia. It is the most recent known genus of Meridiolestida, an extinct group of mammals more closely related to therians (marsupials and placentals) than to monotremes, which were the dominant mammals in South America during the Late Cretaceous. It contains two species, N. patagonensis and N. mirabilis; the type species N. patagonensis was named by Florentino Ameghino in 1891 based on remains f

species of mammal (fossil)

Reigitherium was a mammal that lived during the Late Cretaceous (Late Campanian-Maastrichtian). Its fossils have been found in the Los Alamitos and the La Colonia Formations of Argentina.

Leonardus is an extinct mammal genus from the Late Cretaceous (Late Santonian to Maastrichtian) of South America. It is a meridiolestidan, closely related to the also Late Cretaceous Cronopio and the Miocene Necrolestes.

Peligrotherium is an extinct meridiolestidan mammal from the Paleocene of Patagonia, originally interpreted as a stem-ungulate (though it did co-exist with early meridiungulates). Its remains have been found in the Salamanca Formation. Around the size of a dog, it was among the largest of all non-therian mammals, and the largest non-therian mammal known from South America. It is a member of Mesungulatoidea, a clade of herbivorous meridiolestidans with molars that had rounded (bunodont) cusps.

Orretherium (meaning "Five teeth beast"; in part from the Aonikenk language) is a genus of mesungulatid mammal that lived in South America (Chile) during the Late Cretaceous period in what is now the Dorotea Formation. It is estimated to have weighed ~1.3kg.

Coloniatherium is a meridiolestid mammal from the Late Cretaceous of Argentina. The single species, Coloniatherium cilinskii, was a large member of the family Mesungulatidae.

Austrotriconodon is a mammal genus from the Campanian and Maastrichtian of South America. It currently contains only the type species, A. mckennai. Originally assumed to be a eutriconodont, more recent studies have recovered it as a meridiolestidan dryolestoid.