An additional basal sauropodomorph specimen from the Upper Triassic Caturrita Formation, southern Brazil, with comments on the biogeography of plateosaurids

Autor(es)

Bittencourt, Jonathas S. ^[1] ; Leal, Luciano A. ^[2] ; Langer, Max C. ^[1] ; Azevedo, Sergio A. K. ^[3]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Biol, Lab Paleontol, BR-1404901 Ribeirao Preto, SP - Brazil

^[2] Univ Estadual Sudoeste Bahia, Dept Ciencias Biol, BR-45206190 Jequie, BA - Brazil

^[3] Univ Fed Rio de Janeiro, Dept Geol Paleontol, Lab Processamento Imagem Digital, Museu Nacl, BR-20940040 Rio De Janeiro, RJ - Brazil

• Tipo de documento: Artigo Científico
• Fonte: ALCHERINGA; v. 36, n. 2, p. 269-278, 2012.
• Citações Web of Science: 8

Resumo

We describe an additional saurischian specimen from the Caturrita Formation (Norian) of the Parana Basin, southern Brazil. This material was collected in the 1950s and remained unstudied due to its fragmentary condition. Detailed comparisons with other saurischians worldwide reveal that some characters of the ilium, including the low ventral projection of the medial wall of the acetabulum and its concave ventral margin, together with the short triangular shape of the pre-acetabular process and its mound-like dorsocaudal edge, resemble those of sauropodomorphs such as Plateosaurus and Riojasaurus. This set of traits suggests that MN 1326-V has affinities with basal Sauropodomorpha, probably closer to plateosaurians than to Saturnalia-like taxa. Previous records of this clade in the Caturrita Formation include Unaysaurus, which has been related to Plateosaurus within Plateosauridae. Alternative schemes suggest that plateosaurids include Plateosaurus plus the Argentinean `prosauropods' Coloradisaurus and Riojasaurus. Both hypotheses raise biogeographic questions, as a close relationship between faunas from South America and Europe excluding Africa and North America is not supported by geological and biostratigraphical evidence. Additionally, the absence of plateosaurids in other continents suggests that the geographical distribution of this taxon is inconsistent with the geological history of western Pangaea, and this demands further investigations of the phylogeny of sauropodomorphs or improved sampling. (AU)

• Processo FAPESP: 10/08891-3 - Anatomia e sistemática dos dinossauromorfos da Formação Chañares, Ladiniano da Argentina, e a origem dos dinossauros
• Beneficiário: Jonathas de Souza Bittencourt Rodrigues
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado