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 neotheropod 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.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Barrett PM, Butler RJ, Nesbitt SJ (2011) The roles of herbivory and omnivory in early dinosaur evolution. Earth Environ Sci Trans R Soc Edinburgh 101:383–396. doi:10.1017/S1755691011020111
Ezcurra MD (2007) The cranial anatomy of the coelophysoid theropod Zupaysaurus rougieri (Upper Triassic, Argentina). Historical Biol 19:185–202. doi:10.1080/08912960600861467
Ezcurra MD (2010) A new early dinosaur (Saurischia: Sauropodomorpha) from the Late Triassic of Argentina: a reassessment of dinosaur origin and phylogeny. J Syst Palaeontol 8:371–425. doi:10.1080/14772019.2010.484650
Galton PM (1990) Basal Sauropodomorppha–Prosauropoda. In: Weishampel DB, Dodson P, Osmólska H (eds) The Dinosauria. University of California Press, Berkeley, pp 320–344
Gauthier J (1986) Saurischian monophyly and the origin of birds. In: Padian K (ed) The origin of birds and the evolution of flight. Memoirs of the California Academy of Sciences, no. 8, pp 1–55
Gower DJ (1999) The cranial and mandibular osteology of a new rauisuchian archosaur from the Middle Triassic of southern Germany. Stuttgarter Beitr Naturkde B 280:1–49
Irmis RB (2011) Evaluating hypotheses for the early diversification of dinosaurs. Earth Environ Sci Trans R Soc Edinburgh 101:397–426. doi:10.1017/S1755691011020068
Kellner AWA (2003) Pterosaur phylogeny and comments on the evolutionary history of the group. In: Buffetaut E, Mazin J-M (eds) Evolution and palaeobiology of pterosaurs. Geological Society, London, pp 105–137
Langer MC (2003) The sacral and pelvic anatomy of the stem-sauropodomorph Saturnalia tupiniquim (Late Triassic, Brazil). PaleoBios 23(2):1–40
Langer MC (2004) Basal Saurischia. In: Weishampel DB, Dodson P, Osmólska H (eds) The Dinosauria, 2nd edn. University of California Press, Berkeley, pp 25–46
Langer MC, Benton MJ (2006) Early dinosaurs: a phylogenetic study. J Syst Palaeontol 4:309–358. doi:10.1017/S1477201906001970
Langer MC, Abdala F, Richter M, Benton MJ (1999) A sauropodomorph dinosaur from the Upper Triassic (Carnian) of souther Brazil. C R Acad Sci IIA 329:511–517
Langer MC, Ribeiro AM, Schultz CL, Ferigolo J (2007) The continental tetrapod-bearing Triassic of south Brazil. In: Lucas SG, Spielman JA (eds) The global Triassic. New Mexico Mus Nat Hist & Sci Bull 41:201–218. Available at http://econtent.unm.edu/u?/bulletins,298
Langer MC, Bittencourt JS, Schultz CL (2011) A reassessment of the basal dinosaur Guaibasaurus candelariensis, from the Late Triassic Caturrita Formation of south Brazil. Earth Environ Sci Trans R Soc Edinburgh 101:301–332. doi:10.1017/S175569101102007X
Martinez RN, Alcober AO (2009) A basal sauropodomorph (Dinosauria: Saurischia) from the Ischigualasto Formation (Triassic, Carnian) and the early evolution of Sauropodomorpha. PLoS One 4:e4397. doi:10.1371/journal.pone.0004397
Martinez RN, Sereno PC, Alcober OA, Colombi CE, Renne PR, Montañez IP, Currie BS (2011) A basal dinosaur from the dawn of the dinosaur era in southwestern Pangaea. Science 331:206–210. doi:10.1126/science.1198467
Nesbitt SJ (2011) The early evolution of archosaurs: relationships and the origin of major clades. Bull Am Mus Nat Hist 352:1–292. doi:10.1206/352.1
Nesbitt SJ, Irmis RB, Parker WG, Smith ND, Turner AH, Rowe T (2009) Hindlimb osteology and distribution of basal dinosauromorphs from the Late Triassic of North America. J Vert Paleontol 29:498–516. doi:10.1671/039.029.0218
Nesbitt SJ, Sidor CA, Irmis RB, Angielczyk KD, Smith RMH, Tsuji LA (2010) Ecologically distinct dinosaurian sister group shows early diversification of Ornithodira. Nature 464:95–98. doi:10.1038/nature08718
Novas FE (1996) Dinosaur monophyly. J Vert Paleontol 16:723–741
Padian K, May CL (1993) The earliest dinosaurs. New Mexico Mus Nat Hist & Sci Bull 3:379–381
Rauhut OWM (2003) The interrelationships and evolution of basal theropod dinosaurs. Spec Pap Palaeontol 69:1–213
Salgado L, Coria RA, Calvo JO (1997) Evolution of titanosaurid sauropods. I. Phylogenetic analysis based on the postcranial evidence. Ameghiniana 34:3–32
Sereno PC, Novas FE (1994) The skull and neck of the basal theropod Herrerasaurus ischigualastensis. J Vert Paleontol 13:451–476. doi:10.1080/02724634.1994.10011525
Sereno PC, Forster CA, Rogers RR, Monetta AM (1993) Primitive dinosaur skeleton from Argentina and the early evolution of the Dinosauria. Nature 361:64–66. doi:10.1038/361064a0
Tykoski R (1995) Osteology, ontogeny, and relationships of the coelophysoid theropods. The University of Texas, Austin
Tykoski RS, Rowe T (2004) Ceratosauria. In: Weishampel DB, Dodson P, Osmólska H (eds) The Dinosauria, 2nd edn. University of California Press, Berkeley, pp 47–70
Wu X-C, Russell A (2001) Redescription of Turfanosuchus dabanensis (Archosauriformes) and new information on its phylogenetic relationships. J Vert Paleontol 21:40–50
Yates AM (2003) A new species of the primitive dinosaur, Thecodontosaurus (Saurischia: Sauropodomorpha), and its implications for the systematics of early dinosaurs. J Syst Palaeontol 1:1–42. doi:10.1017/S1477201903001007
Yates AM (2005) A new theropod dinosaur from the Early Jurassic of South Africa and its implication for the early evolution of theropods. Palaeontol Afr 41:105–122. doi:10.1038/nature07855
Zerfass H, Lavina EL, Schultz CL, Garcia AGV, Faccini UF, Chemale F Jr (2003) Sequence stratigraphy of continental Triassic strata of southernmost Brazil: a contribution to Southwestern Gondwana palaeogeography and palaeoclimate. Sedim Geol 161:85–105. doi:10.1016/S0037-0738(02)00397-4
Acknowledgments
Aspects of this work were funded by Conselho Nacional de Desenvolvimento Científico e Tecnológico, Universidade Luterna do Brasil (to S.F.C), and Fundação de Amparo à Pesquisa do Estado de São Paulo (to M.C.L. and J.S.B.). This is contribution no. 25 of Laboratório de Paleontologia, FFCLRP-USP. Thanks to Luiz Flávio Lopes for the photographic work, to Maíra Massarani for the drawing of Fig. 2, and to three anonymous reviewers for their comments.
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by: Robert Reisz
Electronic supplementary material
Below is the link to the electronic supplementary material.
ESM 1
(PDF 1348 kb)
Rights and permissions
About this article
Cite this article
Cabreira, S.F., Schultz, C.L., Bittencourt, J.S. et al. New stem-sauropodomorph (Dinosauria, Saurischia) from the Triassic of Brazil. Naturwissenschaften 98, 1035–1040 (2011). https://doi.org/10.1007/s00114-011-0858-0
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00114-011-0858-0