, 98:389 | Cite as

Associated skeletons of a new middle Triassic “Rauisuchia” from Brazil

  • Marco Aurélio G. França
  • Jorge Ferigolo
  • Max C. LangerEmail author
Original Paper


For more than 30 million years, in early Mesozoic Pangea, “rauisuchian” archosaurs were the apex predators in most terrestrial ecosystems, but their biology and evolutionary history remain poorly understood. We describe a new “rauisuchian” based on ten individuals found in a single locality from the Middle Triassic (Ladinian) Santa Maria Formation of southern Brazil. Nine articulated and associated skeletons were discovered, three of which have nearly complete skulls. Along with sedimentological and taphonomic data, this suggests that those highly successful predators exhibited some kind of intraspecific interaction. Other monotaxic assemblages of Triassic archosaurs are Late Triassic (Norian-Rhaetian) in age, approximately 10 million years younger than the material described here. Indeed, the studied assemblage may represent the earliest evidence of gregariousness among archosaurs, adding to our knowledge on the origin of a behavior pattern typical of extant taxa.


Santa Maria Formation Archosauria Rauisuchia Behavior Middle Triassic 



The fossils described here were collected during the BID “Pró-1 Guaiba” project (to JF). Additional financial support was provided by FAPESP (scholarship 2007/54695-9, grant to MAGF; project 2009/54645-7, grant to MCL). We thank A. M. Ribeiro, curator at MCN FZB-RS, and Claudio Bartolaz (Museu Pde. Daniel Cargnin), who prepared part of the fossil material. Thanks also to C. L. Schultz (UFRGS), J. Powell (PVL), S. Martin (PULR), R. Martinez (PVSJ), and O. Rauhut (BPSG) for permission to examine specimens under their care. The authors thank D. Pol for comments on a previous version of this paper.

Supplementary material

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Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Marco Aurélio G. França
    • 1
  • Jorge Ferigolo
    • 2
  • Max C. Langer
    • 1
    Email author
  1. 1.Laboratório de Paleontologia de Ribeirão Preto, FFCLRPUniversidade de São PauloRibeirão PretoBrazil
  2. 2.Museu de Ciências Naturais, Fundação Zoobotânica do Rio Grande do SulPorto AlegreBrazil

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