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Osteology of the first skull of Aetosauroides scagliai Casamiquela 1960 (Archosauria: Aetosauria) from the Upper Triassic of southern Brazil (Hyperodapedon Assemblage Zone) and its phylogenetic importance.
PLoS One. 2018; 13(8):e0201450.Plos

Abstract

Aetosauria, which includes 30 species, is a diverse group of armored pseudosuchian archosaurs restricted to Upper Triassic beds. Three species occur in Brazil, and one of these, Aetosauroides scagliai Casamiquela, 1960, also occurs in Argentina. The specimen UFSM 11505, found at Faixa Nova-Cerrito I Outcrop, Santa Maria Formation (Hyperodapedon Assemblage Zone), Santa Maria, Rio Grande do Sul State, Brazil, is here referred to as Aetosauroides scagliai. This specimen preserves most of the skull with both hemimandibles in association with most of the postcranium, thus representing one of the most complete aetosaur skeletons found in Brazil. The premaxilla, one of the key elements of the cranial morphology of aetosaurs, along with the posterior portion of the mandible, was not described until now for A. scagliai. In contrast to the typothoracinae aetosaurs, the premaxilla of UFSM 11505 presents a shovel-shaped tip, but it is not as prominent as the lateral expansion of desmatosuchian aetosaurs, including both species of Stagonolepis, S. robertsoni Agassiz, 1844 and S. olenkae Sulej, 2010. The retroarticular process of the mandible is elongate and not tall, as in Stenomity huangae Small & Martz, 2013 and other typothoracinae aetosaurs. Unlike previous descriptions of A. scagliai, the maxillary teeth are recurved ziphodont-like with serrations on the entire length of both margins. Premaxillary teeth are also present, being less recurved than the maxillary teeth and cylindrical. We recovered Aetosauroides scagliai as the most basal taxon within Aetosauria, like previous phylogenetic analyses. Furthermore, our analyses reinforce that recurved and unconstricted maxillary teeth, the shovel-shaped premaxilla and the presence of a tuber on the surangular are plesiomorphic features of Aetosauria.

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Authors+Show Affiliations

Biacchi Brust AC
Programa de Pós-Graduação em Geociências, Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Desojo JB
División Paleontología Vertebrados, Museo de La Plata, Facultad de Ciencias Naturales y Museo, La Plata, Buenos Aires, Argentina.
Schultz CL
Departamento de Paleontologia e Estratigrafia, Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Paes-Neto VD
Programa de Pós-Graduação em Geociências, Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Da-Rosa ÁAS
Departamento de Geociências, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.

MeSH

AnimalsBrazilDinosaursFossilsPhylogenySkull

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

30110362

Citation

Biacchi Brust, Ana Carolina, et al. "Osteology of the First Skull of Aetosauroides Scagliai Casamiquela 1960 (Archosauria: Aetosauria) From the Upper Triassic of Southern Brazil (Hyperodapedon Assemblage Zone) and Its Phylogenetic Importance." PloS One, vol. 13, no. 8, 2018, pp. e0201450.
Biacchi Brust AC, Desojo JB, Schultz CL, et al. Osteology of the first skull of Aetosauroides scagliai Casamiquela 1960 (Archosauria: Aetosauria) from the Upper Triassic of southern Brazil (Hyperodapedon Assemblage Zone) and its phylogenetic importance. PLoS One. 2018;13(8):e0201450.
Biacchi Brust, A. C., Desojo, J. B., Schultz, C. L., Paes-Neto, V. D., & Da-Rosa, Á. A. S. (2018). Osteology of the first skull of Aetosauroides scagliai Casamiquela 1960 (Archosauria: Aetosauria) from the Upper Triassic of southern Brazil (Hyperodapedon Assemblage Zone) and its phylogenetic importance. PloS One, 13(8), e0201450. https://doi.org/10.1371/journal.pone.0201450
Biacchi Brust AC, et al. Osteology of the First Skull of Aetosauroides Scagliai Casamiquela 1960 (Archosauria: Aetosauria) From the Upper Triassic of Southern Brazil (Hyperodapedon Assemblage Zone) and Its Phylogenetic Importance. PLoS One. 2018;13(8):e0201450. PubMed PMID: 30110362.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Osteology of the first skull of Aetosauroides scagliai Casamiquela 1960 (Archosauria: Aetosauria) from the Upper Triassic of southern Brazil (Hyperodapedon Assemblage Zone) and its phylogenetic importance. AU - Biacchi Brust,Ana Carolina, AU - Desojo,Julia Brenda, AU - Schultz,Cesar Leandro, AU - Paes-Neto,Voltaire Dutra, AU - Da-Rosa,Átila Augusto Stock, Y1 - 2018/08/15/ PY - 2017/08/04/received PY - 2018/07/16/accepted PY - 2018/8/16/entrez PY - 2018/8/16/pubmed PY - 2019/1/24/medline SP - e0201450 EP - e0201450 JF - PloS one JO - PLoS One VL - 13 IS - 8 N2 - Aetosauria, which includes 30 species, is a diverse group of armored pseudosuchian archosaurs restricted to Upper Triassic beds. Three species occur in Brazil, and one of these, Aetosauroides scagliai Casamiquela, 1960, also occurs in Argentina. The specimen UFSM 11505, found at Faixa Nova-Cerrito I Outcrop, Santa Maria Formation (Hyperodapedon Assemblage Zone), Santa Maria, Rio Grande do Sul State, Brazil, is here referred to as Aetosauroides scagliai. This specimen preserves most of the skull with both hemimandibles in association with most of the postcranium, thus representing one of the most complete aetosaur skeletons found in Brazil. The premaxilla, one of the key elements of the cranial morphology of aetosaurs, along with the posterior portion of the mandible, was not described until now for A. scagliai. In contrast to the typothoracinae aetosaurs, the premaxilla of UFSM 11505 presents a shovel-shaped tip, but it is not as prominent as the lateral expansion of desmatosuchian aetosaurs, including both species of Stagonolepis, S. robertsoni Agassiz, 1844 and S. olenkae Sulej, 2010. The retroarticular process of the mandible is elongate and not tall, as in Stenomity huangae Small & Martz, 2013 and other typothoracinae aetosaurs. Unlike previous descriptions of A. scagliai, the maxillary teeth are recurved ziphodont-like with serrations on the entire length of both margins. Premaxillary teeth are also present, being less recurved than the maxillary teeth and cylindrical. We recovered Aetosauroides scagliai as the most basal taxon within Aetosauria, like previous phylogenetic analyses. Furthermore, our analyses reinforce that recurved and unconstricted maxillary teeth, the shovel-shaped premaxilla and the presence of a tuber on the surangular are plesiomorphic features of Aetosauria. SN - 1932-6203 UR - https://www.unboundmedicine.com/medline/citation/30110362/Osteology_of_the_first_skull_of_Aetosauroides_scagliai_Casamiquela_1960__Archosauria:_Aetosauria__from_the_Upper_Triassic_of_southern_Brazil__Hyperodapedon_Assemblage_Zone__and_its_phylogenetic_importance_ DB - PRIME DP - Unbound Medicine ER -