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A new prozostrodontian cynodont (Therapsida) from the Late Triassic Riograndia Assemblage Zone (Santa Maria Supersequence) of Southern Brazil.

Authors :
Soares MB
Martinelli AG
De Oliveira TV
Source :
Anais da Academia Brasileira de Ciencias [An Acad Bras Cienc] 2014 Dec; Vol. 86 (4), pp. 1673-92. Date of Electronic Publication: 2014 Nov 28.
Publication Year :
2014

Abstract

We report here on a new prozostrodontian cynodont, Botucaraitherium belarminoi gen. et sp. nov., from the Late Triassic Riograndia Assemblage Zone (AZ) of the Candelária Sequence (Santa Maria Supersequence), collected in the Botucaraí Hill Site, Candelária Municipality, state of Rio Grande do Sul, Brazil. The new taxon is based on a single specimen (holotype MMACR-PV-003-T) which includes the left lower jaw, without postdentary bones, bearing the root of the last incisor, canine and four postcanines plus one partial crown inside the dentary, not erupted, and two maxillary fragments, one with a broken canine and another with one postcanine. The features of the lower jaw and lower/upper postcanines resemble those of the prozostrodontians Prozostrodon brasiliensis from the older Hyperodapedon AZ and Brasilodon quadrangularis and Brasilitherium riograndensis from the same Riograndia AZ. The inclusion of Botucaraitherium within a broad phylogenetic analysis, positioned it as a more derived taxon than tritylodontids, being the sister-taxon of Brasilodon, Brasilitherium plus Mammaliaformes. Although the new taxon is based on few cranial elements, it represents a additional faunal component of the Triassic Riograndia AZ of southern Brazil, in which small-sized derived non-mammaliaform cynodonts, closely related to the origin of mammaliaforms, were ecologically well succeed and taxonomically diverse.

Details

Language :
English
ISSN :
1678-2690
Volume :
86
Issue :
4
Database :
MEDLINE
Journal :
Anais da Academia Brasileira de Ciencias
Publication Type :
Academic Journal
Accession number :
25590707
Full Text :
https://doi.org/10.1590/0001-3765201420140455