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Type: Article
Published: 2018-08-09
Page range: 351–378
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Skull anatomy and phylogenetic assessment of a large specimen of Ecteniniidae (Eucynodontia: Probainognathia) from the Upper Triassic of southern Brazil

Programa de Pós-Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria, 97105-120 Santa Maria, RS, Brazil.
Programa de Pós-Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria, 97105-120 Santa Maria, RS, Brazil.
2Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia, Universidade Federal de Santa Maria, Rua Maximiliano Vizzotto, 598, 97230-000 São João do Polêsine, RS, Brazil.
Instituto y Museo de Ciencias Naturales, Universidad Nacional de San Juan, Av. España, 400 (norte), 5400 San Juan, Argentina.
Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia, Universidade Federal de Santa Maria, Rua Maximiliano Vizzotto, 598, 97230-000 São João do Polêsine, RS, Brazil.
Candelária Sequence. Carnian. Late Triassic. Janner outcrop. Probainognathians. Phylogeny. South America Mammalia


Ecteniniidae comprises an endemic radiation of carnivore probainognathian cynodonts from the Late Triassic of South America. Three taxa have been included in this clade: Ecteninion lunensis Martínez et al., 1996 and Diegocanis elegans Martínez et al., 2013 from Argentina, and Trucidocynodon riograndensis Oliveira et al., 2010 from Brazil. Herein, a new specimen (skull and mandible) assigned to T. riograndensis from the Carnian of the Candelária Sequence (Southern Brazil) is described. A phylogenetic analysis recovered the new specimen as the sister taxon of the holotype of T. riograndensis, and both in a trichotomy with E. lunensis and D. elegans, all supporting the monophyly of Ecteniniidae. The new specimen of T. riograndensis is almost 20% larger than its holotype. Therefore, it represents one of the largest specimens of a carnivorous probainognathian from the Late Triassic known to date and contributes to knowledge of size variation in ecteniniids.


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