''Cifellilestes'' is a genus of early

mammaliaform Mammaliaformes ("mammalian forms") is a clade of synapsid tetrapods that includes the crown group mammals and their closest extinct relatives; the group radiated from earlier probainognathian cynodonts during the Late Triassic. It is defined a ...

from the

Late Jurassic The Late Jurassic is the third Epoch (geology), epoch of the Jurassic Period, and it spans the geologic time scale, geologic time from 161.5 ± 1.0 to 143.1 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic stratum, strata.Owen ...

Morrison Formation The Morrison Formation is a distinctive sequence of Upper Jurassic sedimentary rock found in the western United States which has been the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandstone, siltston ...

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 ...

. The type and only species, ''C. ciscoensis'', was named in 2022 by Brian M. Davis and colleagues, and was found in the Cisco Mammal Quarry of

Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...

. The generic name of the animal is in honor of Richard Cifelli, combined with the Greek word "lestes", which means thief. The specific name refers to Cisco, Utah, a ghost town close in close proximity to the location where the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

was found. The genus is known from two specimens, OMNH 80538 & 69352. These specimens represent a right and left skull fragment respectively, both preserving partial palate, snout and postcanine dentition. It belongs to the clade

Morganucodonta Morganucodonta ("Glamorgan teeth") is an extinct Order (biology), order of basal Mammaliaformes, a group including crown-group mammals (Mammalia) and their close relatives. Their remains have been found in Southern Africa, Western Europe, North A ...

References

Morganucodonta Tithonian genera Late Jurassic synapsids of North America Morrison fauna Fossil taxa described in 2022 Monotypic prehistoric animal genera {{Paleo-cynodont-stub