sexta-feira, 25 de março de 2011

Dental Occlusion in a 260-Million-Year-Old Therapsid with Saber Canines from the Permian of Brazil

  1. Juan Carlos Cisneros1,2,
  2. Fernando Abdala3,
  3. Bruce S. Rubidge3,
  4. Paula Camboim Dentzien-Dias4, and
  5. Ana de Oliveira Bueno2
+ Author Affiliations
  1. 1Universidade Federal do Piauí, Centro de Ciências da Natureza, 64049-550, Ininga, Teresina, Piauí, Brazil.
  2. 2Universidade Federal do Rio Grande do Sul, Departamento de Paleontologia e Estratigrafia, Avenida Bento Gonçalves 9500, Porto Alegre, Rio Grande do Sul, Brazil.
  3. 3Bernard Price Institute for Palaeontological Research, University of the Witwatersrand, Private Bag 3, WITS 2050, Johannesburg, South Africa.
  4. 4Universidade Federal do Piauí, Picos, Piauí, Brazil.

Abstract

Anomodonts, a group of herbivorous therapsid “mammal-like reptiles,” were the most abundant tetrapods of the Permian. We present a basal anomodont from South America, a new taxon that has transversally expanded palatal teeth and long saber canines. The function of the saber teeth is unknown, but probable uses include deterring attack from predators and intraspecific display or combat. The complex palatal teeth were used to process high-fiber food and represent early evidence of dental occlusion in a therapsid. This discovery provides new insight into the evolution of heterogeneous dentition in therapsids and broadens our understanding of ecological interactions at the end of the Paleozoic. 

  • Received for publication 10 November 2010.
  • Accepted for publication 2 February 2011.

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