Probainognathidae is an extinct family of meat-eating mammal-like reptiles (Therapsids) which lived during the Upper Triassic

Triassic

The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...

. According to some authors, it has perhaps two known members: Probainognathus

Probainognathus

Probainognathus is a genus of meat-eating mammal-like reptile that lived during the lower Upper Triassic of South America. This creature had an incipient squamosal-dentary jaw-cranium joint, which is a clearly mammalian anatomical feature. It was at the very least closely related to the family of...

from South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

, and the somewhat later Lepagia

Lepagia

Lepagia is a poorly known genus of meat-eating mammal-like reptile, , which lived during the Upper Triassic in Europe. Partly due to the paucity of remains the precise affinities of this genus are unclear. It seems reasonably closely related to Probainognathus, a somewhat earlier inhabitant of...

from Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

. The family was established by Romer in 1973. Its members were closely related to the even more exotically named Chiniquodontidae

Chiniquodontidae

Chiniquodontidae is a family of meat-eating advanced mammal-like reptiles that lived during the Upper Triassic of South America and perhaps Europe. A further possible representative, Aleodon, has been identified from the Middle Triassic of Africa...

.

Both genera

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 were small animals. Probainognathus

Probainognathus

Probainognathus is a genus of meat-eating mammal-like reptile that lived during the lower Upper Triassic of South America. This creature had an incipient squamosal-dentary jaw-cranium joint, which is a clearly mammalian anatomical feature. It was at the very least closely related to the family of...

, known from a number of specimens, was about 10 cm in length and extremely mammal

Mammal

Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

-like in terms of its anatomy

Anatomy

Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...

. Remains of Lepagia

Lepagia

Lepagia is a poorly known genus of meat-eating mammal-like reptile, , which lived during the Upper Triassic in Europe. Partly due to the paucity of remains the precise affinities of this genus are unclear. It seems reasonably closely related to Probainognathus, a somewhat earlier inhabitant of...

are restricted to teeth. These most closely resemble the dentition of other carnivorous cynodonts of the Upper Triassic.