Wikipedia
Kuehneotherium is an early mammaliaform genus that lived during the late Triassic period and is characterized by reversed-triangle pattern of molar cusps. Although a large number of fossils have been found, the fossils are limited to teeth, dental fragments, and mandible fragments. The genus includes Kuehneotherium praecursoris and all related species. It was first named and described by Doris M. Kermack, K. A. Kermack, and Frances Mussett in November 1967. The family Kuehneotheriidae and the genus Kuehneotherium were created to house the single species Kuehneotherium praecursoris. Modeling based upon a comparison of the Kuehneotherium jaw with other mammals indicates they were about the size of a modern day shrew between 4 and 5.5 g at adulthood.
Kuehneotherium is thought to be an insectivore that could consume only soft-bodied insects such as moths. Their teeth were shaped for vertical shearing and could not crush harder prey. They lived alongside another early mammal, Morganucodon, which had teeth that could crush harder insects such as beetles. This distinction in diet shows that early mammals adapted to have a separate feeding niche so they would not compete for food.