Rosieria is a genus

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...

 of dwarf cynodont

Cynodont

Cynodontia or cynodonts are a taxon of therapsids which first appeared in the Late Permian and were eventually distributed throughout all seven continents by the Early Triassic . This clade includes modern mammals and their extinct close relatives. They were one of the most diverse groups of...

 from the Late Triassic

Late Triassic

The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...

 of France

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

. It belongs to the family Traversodontidae

Traversodontidae

Traversodontidae is a family of herbivorous cynodonts. Traversodonts were primarily Gondwanan, with many species known from Africa and South America. Recently, traversodonts have also been found from Europe and eastern North America. Traversodonts first appeared in the Middle Triassic, diversified...

, a herbivorous group known mainly from Gondwana

Gondwana

In paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinents that later became parts of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago . Gondwana is believed to have sutured between ca. 570 and 510 Mya,...

. The type species R. delsatei was named in 1997 on the basis of a few isolated postcanine teeth found in Saint-Nicolas-de-Port

Saint-Nicolas-de-Port

Saint-Nicolas-de-Port is a commune in the Meurthe-et-Moselle département in north-eastern France.Its inhabitants are known asPortois. In the past, the Portois were known as loudmouths; their neighbours across the Meurthe at Varangéville liked to gather on the opposite river bank to bombard them...

 in northeastern France. These teeth were found alongside the teeth of many other cynodonts, including those of Hahnia

Hahnia

Hahnia is a poorly known genus of meat-eating mammal-like reptiles that lived during the Upper Triassic in Europe. This genus is based on tiny, isolated teeth, and its affinities with other cynodonts are unclear. The generic name is invalid, thus the inverted commas. The name Hahnia has already...

, Gaumia, and Maubeugia

Maubeugia

Maubeugia is a genus of traversodontid cynodont from the Late Triassic of France. Isolated postcanine teeth are known from Saint-Nicolas-de-Port in northeastern France. The type species M. lotharingica was named in 1997. Many other cynodont teeth were found alongside those of Maubeugia, including...

. The small size of the teeth in Saint-Nicolas-de-Port suggest R. delsatei and other species were dwarf cynodonts. Most teeth in the locality belong to insectivores like dromatheriids, while those of R. delsatei and other herbivorous cynodonts are very rare.