Adelobasileus

Adelobasileus; Temporal range: Late Triassic, 225 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
	Life restoration
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Synapsida
Clade:	Therapsida
Clade:	Cynodontia
Clade:	Mammaliamorpha
Genus:	†Adelobasileus; Lucas & Hunt, 1990
Species:	†A. cromptoni
Binomial name
	†Adelobasileus cromptoni; Lucas & , 1990

Adelobasileus is a genus of mammaliamorph cynodonts from the Late Triassic (Carnian), about 225 million years ago. It is known only from a partial skull recovered from the Tecovas Formation in western Texas, southern United States, referred to the species Adelobasileus cromptoni.

Roughly contemporary with the mammaliaform Tikitherium, Adelobasileus predates the non-mammalian cynodonts Tritylodontidae and Tritheledontidae by 10 million years. Distinct cranial features, especially the housing of the cochlea, suggest that Adelobasileus is a transitional form in the character transformation from non-mammaliaform cynodonts to mammaliaforms. For this reason, it is thought to be a close relative of the common ancestor of all modern mammals. Though traditionally classified as a mammal by trait-based taxonomy, it is outside the crown group containing all true mammals.^[1]

References[]

^ Rowe, T. S. (1988). "Definition, diagnosis, and origin of Mammalia" (PDF). Journal of Vertebrate Paleontology. 8 (3): 241–264. doi:10.1080/02724634.1988.10011708.

Sources[]

Lucas, SG; Hunt, AP (1990). "The oldest mammal". New Mexico Journal of Science. 30 (1): 41–49.
Lucas, SG; Luo, Z (September 1993). "Adelobasileus from the upper Triassic of west Texas: the oldest mammal". J. Vertebr. Paleontol. 13 (3): 309–334. doi:10.1080/02724634.1993.10011512.