Prozostrodon

Prozostrodon; Temporal range: Carnian; ~233.23 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
	Skull of holotype
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Synapsida
Clade:	Therapsida
Clade:	Cynodontia
Clade:	Prozostrodontia
Genus:	†Prozostrodon; Bonaparte & Barbarena, 2001
Species:	†P. brasiliensis
Binomial name
	†Prozostrodon brasiliensis; (Bonaparte & Barbarena, 2001)
Synonyms
	Thrinaxodon brasiliensis Barberena et al. 1987;

Limb bone osteohistology of P. brasiliensis^[1]

Prozostrodon is an extinct genus of advanced cynodonts that was closely related to the ancestors of mammals. The remains were found in Brazil and are dated middle to late Triassic. It was originally described as a species of Thrinaxodon^[2] and was probably fairly similar to that genus in overall build. The holotype has a skull length of 6.7 cm, indicating the whole animal may have been the size of a cat, though there is some doubt as to whether the find represents an adult individual. The teeth were typical of advanced cynodonts, and the animal was probably a small carnivore hunting reptiles and other small prey.^[3]

Later analysis indicated Prozostrodon was more closely related to the mammals than to the Thrinaxodon species, and it was given its own genus. Cladistic analysis indicates its closest relatives gave rise to the first mammaliaforms and therefore to the crown group mammals. The holotype of Prozostrodon was found in the Geopark of Paleorrota, Santa Maria Formation, Brazil and is deposited in the paleontology museum of the UFRGS.^[4]

A second specimen was described in 2018 from the Candelária Formation of the Paraná Basin.^[5]

References[]

^ Botha-Brink et al., 2018, p.9
^ Barberena, M.C, J. F. Bonaparte, J.F. & Teixeira, A.M.SA (1987): Thrinaxodon brasiliensis sp. nov., a primeira ocorrencia de cinodontes gales - sauros para o Triasico do Rio Grande do Sul. Anais do X Congresso Brasileiro de Paleontologia, Rio de Janeiro, Brazil, pp. 67-76.
^ Bonaparte, J.F. and Barberena, M.C. (2001). "On two advanced carnivorous cynodonts from the Late Triassic of Southern Brazil": In: Studies in Organismic and Evolutionary Biology in honor of A. W. Crompton, edited by Jenkins Jr, F.A., Shapiro, M.D., and Owerkowicz, T. Bulletin of the Museum of Comparative Zoology 156 (1): 59-80.
^ "The Continental Tetrapod-Bearing Triassic of South Brazil" (PDF). Archived from the original (PDF) on 2011-06-11. Retrieved 2008-04-29.
^ Pacheco et al., 2018, p.4