''Ursulinacaris'' is a genus of

hurdiid Hurdiidae (synonymous with the previously named Peytoiidae) is an extinct cosmopolitan distribution, cosmopolitan Family (biology), family of radiodonts, a group of Crown group#Stem groups, stem-group marine arthropods, which lived during the Pal ...

radiodont Radiodonta is an extinct order of stem-group arthropods that was successful worldwide during the Cambrian period. Radiodonts are distinguished by their distinctive frontal appendages, which are morphologically diverse and were used for a variety ...

from the

Cambrian The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordov ...

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

. It contains one known species, ''Ursulinacaris grallae''. It was described in 2019, based on fossils of the frontal appendages discovered in the 1990s and thereafter. The endites of ''Ursulinacaris'' were very slender, unlike other hurdiids such as ''

Peytoia ''Peytoia'' is a genus of hurdiid radiodont, an early diverging order of stem-group arthropods, that lived in the Cambrian period, containing two species, ''Peytoia nathorsti'' from the Miaolingian of Canada and '' Peytoia infercambriensis'' fr ...

'' or ''

Hurdia ''Hurdia'' is an extinct genus of Hurdiidae, hurdiid radiodont that lived 505 million years ago during the Cambrian Period. Fossils have been found in North America, China, and the Czech Republic. Taxonomic history ''Hurdia'' was named in 1912 ...

''. It was initially reported as the first hurdiid with paired endites (a feature only present in other non-hurdiid radiodonts), but Moysiuk & Caron (2021) suggested that it is actually the preservation of the fossils and therefore there are no paired endites.

Discovery and naming

''Ursulinacaris'' fossils have been found in the

Northwest Territories The Northwest Territories is a federal Provinces and territories of Canada, territory of Canada. At a land area of approximately and a 2021 census population of 41,070, it is the second-largest and the most populous of Provinces and territorie ...

and

Nevada Nevada ( ; ) is a landlocked state in the Western United States. It borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the seventh-most extensive, th ...

. Most specimens come from the Little Bear biota of the Mount Cap Formation, though one referred specimen is from the Jangle Limestone member of the Carrara Formation of Nevada. Its generic name refers to the Little Bear biota, being derived from Latin "ursulina" meaning "from little bear" and "caris" meaning "crab". The name of the type species, ''U. grallae'', is derived from the Latin word "grallae," which means "stilts," as a reference to the shape of the spines.

Gallery

References

Radiodonta Fossil taxa described in 2019 {{cambrian-animal-stub