Mesungulatidae is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

clade of

meridiolestida Meridiolestida is an extinct clade of mammals known from the Cretaceous and Cenozoic of South America and possibly Antarctica. They represented the dominant group of mammals in South America during the Late Cretaceous. Meridiolestidans were morp ...

dryolestoid Dryolestida is an extinct order of mammals, primarily and possibly exclusively known from the Jurassic and Cretaceous. They are considered members of the clade Cladotheria, close to the ancestry of therian mammals. It is also believed that they d ...

mammals from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

and possibly other Gondwannan landmasses. They are particularly notable for their ecological speciation and large size.

Characteristics

Most mesungulatids are generally large animals, making them inherently distinctive from other groups. Specific synapomorphies include a strong precingulum and postcingulum on the upper molars - which are extended lingually but do not meet around the paracone - three cusps on the lower stylar shelf, an absent metacone and rectangular lower molars. They are thought to have had a somewhat transverse mastication, like

docodont Docodonta is an order of extinct mammaliaforms that lived during the Mesozoic, from the Middle Jurassic to Early Cretaceous. They are distinguished from other early mammaliaforms by their relatively complex molar teeth, from which the order get ...

s and modern

ungulate Ungulates ( ) are members of the diverse clade Ungulata which primarily consists of large mammals with hooves. These include odd-toed ungulates such as horses, rhinoceroses, and tapirs; and even-toed ungulates such as cattle, pigs, giraffes, cam ...

s. Compared to other dryolestoids their molar eruption patterns are delayed.

Ecology

Mesungulatids are generally large sized herbivores or omnivores, being among the several Mesozoic mammals deviating from the classical insectivore stereotype. They are among the dominant mammals in Late Cretaceous South American assemblages, and among the most derived species present.

References

{{Taxonbar, from=Q21291080 Dryolestida Cretaceous mammals of South America Late Cretaceous first appearances Late Cretaceous extinctions Mesozoic mammals of South America Prehistoric mammal families