On the occurrence of the traversodontid Massetognathus ochagaviae (Synapsida, Cynodontia) in the early late Triassic Santacruzodon Assemblage Zone (Santa Maria Supersequence, southern Brazil): Taxonomic and biostratigraphic implications
| Autor: | Tomaz Panceri Melo, Maurício Rodrigo Schmitt, Agustín G. Martinelli, Marina Bento Soares |
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| Rok vydání: | 2019 |
| Předmět: |
SANTA MARIA SUPERSEQUENCE
BIOSTRATIGRAPHY biology Outcrop Geology Dinodontosaurus Biostratigraphy biology.organism_classification TRAVERSODONTIDAE Paleontología EUCYNODONTIA Ciencias de la Tierra y relacionadas con el Medio Ambiente Traversodontidae LATE TRIASSIC Cynodont Massetognathus Paleontology Eucynodontia Chañares Formation CIENCIAS NATURALES Y EXACTAS Earth-Surface Processes |
| Zdroj: | Journal of South American Earth Sciences. 93:36-50 |
| ISSN: | 0895-9811 |
| DOI: | 10.1016/j.jsames.2019.04.011 |
| Popis: | The traversodontid cynodont Massetognathus ochagaviae is confirmed for the first time in the Santacruzodon Assemblage Zone (Carnian)of the Upper Santa Maria Supersequence of Brazil. Previously to this record, the taxon was known from the Massetognathus-Chanaresuchus AZ of the Chañares Formation, in Argentina (early Carnian)and the Dinodontosaurus AZ of the Santa Maria Supersequence, Brazil (late Ladinian-early Carnian). The studied material was collected in the Schöenstatt outcrop in Santa Cruz do Sul municipality, state of Rio Grande do Sul. The attribution to the species M. ochagaviae is based on the labial border of the upper postcanines teeth extending outward to form an isosceles triangle, one of the diagnosis features of the species, the subrectangular shape and the presence of a short lingual ridge in the lower postcanines, and others traits shared with M. pascuali and M. ochagaviae, as the general morphology of skull, with a lateral platform on the maxilla, 10 to 12 upper postcanine teeth with posterior cingulum, and up to 11 lower postcanine teeth with the transverse mesial width wider than the distal. A cladistic analysis placed the new specimen as sister-group of M. ochagaviae. The Schöenstatt outcrop is the best-studied fossil-bearing site of the Santacruzodon AZ, in which the traversodontid cynodonts are the dominant faunal components, representing 82% of the collected specimens. The Santacruzodon AZ, correlated to the Malagasy basal “Isalo II” beds of the Morondava Basin, also shares taxa with the Dinodontosaurus AZ and the Chañares and the Ischigualasto formations, representing a unique Triassic association. As a consequence, the Santacruzodon AZ represents a faunal association still not recognized in the Ischigualasto-Villa Unión Basin. New data from the Santacruzodon AZ is required to further address these questions. Fil: Schmitt, Maurício Rodrigo. Universidade Federal do Rio Grande do Sul; Brasil Fil: Martinelli, Agustín Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Melo, Tomaz Panceri. Universidade Federal do Rio Grande do Sul; Brasil Fil: Soares, Marina Bento. Universidade Federal do Rio Grande do Sul; Brasil |
| Databáze: | OpenAIRE |
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