Kuehneotheriidae is a clade

Clade

A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

 within Symmetrodonta

Symmetrodonta

Symmetrodonta is a basal group of Mesozoic mammals characterized by the triangular aspect of the molars when viewed from above and the absence of a well-developed talonid. The traditional group of symmetrodonts ranges in age from the latest Triassic to the Late Cretaceous. One species,...

 and was created to embrace Kuehneotherium

Kuehneotherium

Kuehneotherium was an early symmetrodont whose fossils have been found in Greenland, France and Luxembourg. It is known only from an upper molar as well as nine additional teeth and four dentary fragments.-Further reading:...

and Woutersia

Woutersia

Woutersia was a triassic symmetrodont and the only representative of its family. It has been suggested that it may form the sister taxon to Docodonta. Its remains have been found in France.-Sources:*...

, which lived in 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...

 in the late 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...

 and early Jurassic

Jurassic

The Jurassic is a geologic period and system that extends from about Mya to  Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...

. All members of Kuehneotheriidae which have been found so far are represented only by teeth, but these teeth have features which have led paleontologists

Paleontology

Paleontology "old, ancient", ὄν, ὀντ- "being, creature", and λόγος "speech, thought") is the study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments...

 to classify Kuehneotheriidae as very close relatives of the first true mammals. But fossil clades based solely on teeth often lead to difficulties (Ausktribosphenidae

Ausktribosphenidae

Ausktribosphenidae is a group name that has been given to some rather puzzling fossils—Ausktribosphenos nyktos and Bishops whitmorei—which*Appear to have tribosphenic molars, a type of tooth which is otherwise known only in Therians....

 are a good example), and it is not possible to draw significant conclusions about mammalian evolution from the Kuehneotheriidae - unless someone finds more complete fossils.