ORIGINAL PAPER New stem-sauropodomorph (Dinosauria, Saurischia) from the Triassic of Brazil Sergio F. Cabreira & Cesar L. Schultz & Jonathas S. Bittencourt & Marina B. Soares & Daniel C. Fortier & Lúcio R. Silva & Max C. Langer Received: 22 August 2011 /Revised: 7 October 2011 /Accepted: 13 October 2011 # Springer-Verlag 2011 Abstract Post-Triassic theropod, sauropodomorph, and ornithischian dinosaurs are readily recognized based on the set of traits that typically characterize each of these groups. On the contrary, most of the early members of those lineages lack such specializations, but share a range of generalized traits also seen in more basal dinosauromorphs. Here, we report on a new Late Triassic dinosaur from the Santa Maria Formation of Rio Grande do Sul, southern Brazil. The specimen comprises the disarticulated partial skeleton of a single individual, including most of the skull bones. Based on four phylogenetic analyses, the new dinosaur fits consistently on the sauropodomorph stem, but lacks several typical features of sauropodomorphs, showing dinosaur plesiomorphies together with some neo- theropod traits. This is not an exception among basal dinosaurs, the early radiation of which is characterized by a mosaic pattern of character acquisition, resulting in the uncertain phylogenetic placement of various early members of the group. Keywords Dinosauria, Late Triassic . Santa Maria Formation . Archosauria . Phylogeny Introduction Previous to the discovery of Saturnalia tupiniquim, from the Santa Maria Formation of southern Brazil (Langer et al. 1999), the oldest known members of the sauropodomo- morph lineage were relatively massive, medium to large sized dinosaurs, recovered from Norian aged strata, mainly in Europe, Argentina, and South Africa (Galton 1990). Since then, an unsuspected diversity of smaller, more gracile stem-sauropodomorphs (sensu Langer 2003) was recovered from Carnian deposits of South America, especially from the Ischigualasto Formation, in Argentina. This includes Panphagia protos (Martinez and Alcober 2009), Chromogisaurus novasi (Ezcurra 2010), and possi- bly also Eoraptor lunensis (Martinez et al. 2011), formerly nested within Theropoda (Sereno et al. 1993). Here, we report on a disarticulated but otherwise well-preserved skeleton of a new stem-sauropodomorph from the Late Triassic of southern Brazil (Fig. 1), including most of the skull bones (Fig. 2). Communicated by: Robert Reisz Electronic supplementary material The online version of this article (doi:10.1007/s00114-011-0858-0) contains supplementary material, which is available to authorized users. S. F. Cabreira : L. R. Silva Museu de Ciências Naturais, Universidade Luterana do Brasil (ULBRA), Av. Farroupilha 8001, 92425-900 Canoas, Rio Grande do Sul, Brazil C. L. Schultz : M. B. Soares Departamento de Paleontologia e Estratigrafia, Instituto de Geociências, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, 91540-000 Porto Alegre, Rio Grande do Sul, Brazil J. S. Bittencourt : M. C. Langer (*) Laboratório de Paleontologia de Ribeirão Preto, FFCLRP, Universidade de São Paulo, Av. Bandeirantes 3900, 14040-901 Ribeirão Preto, São Paulo, Brazil e-mail: mclanger@ffclrp.usp.br D. C. Fortier Departamento de Geologia, UFMG, Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil Naturwissenschaften DOI 10.1007/s00114-011-0858-0