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A new early Late Triassic saurischian dinosaur from Rio Grande do Sul State, Brazil

Authors:
  • Museu de Ciências Naturais - SEMA/RS
  • Museu de Ciências Naturais SEMA/RS
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... Espécies como o Sacissauro, por exemplo, tem sido "realocada" dentro dos silesaurídeos, um grupo de répteis que pode muito bem ter uma posição dentro do Clado Dinossauria, formando o ramo basal da linhagem Ornitísquia (Langer e Ferigolo, 2013), mas isso ainda não é consenso entre os pesquisadores. Para As doze espécies de dinossauros do RS são as seguintes: Staurikosaurus pricei (Colbert, 1970), Saturnalia tupiniquim (Langer et al., 1999), Guaibasaurus candelariensis (Bonaparte et al., 1999), Unaysaurus tolentinoi (Leal et al., 2004), Sacisaurus agudoensis (Ferigolo e Langer, 2006), Pampadromaeus barberenai (Cabreira et al., 2011), Buriolestes schultzi (Cabreira et al., 2016) A palavra "tupiniquim" foi escolhida pelos autores para se referir a algo "nativo" ou "tipicamente brasileiro". ...
... Colbert (1970);Langer et al. (1999);Bonaparte et al. (1999);Leal et al. (2004); Ferigolo e Langer(2006); Cabreira et al. (2011); Cabreira et al. (2016); Pretto et al. (2018); Muller et al. (2018); Marsola et al. (2019); Pacheco et al. (2019); Muller (2021). ...
... ;Langer et al. (1999);Bonaparte et al. (1999);Leal et al. (2004); Ferigolo e Langer(2006); Cabreira et al. (2011); Cabreira et al. (2016); Pretto et al. (2018); Muller et al. (2018); Marsola et al. (2019); Pacheco et al. (2019); Muller (2021). ...
Article
A Paleontologia é a ciência que estuda os dinossauros e por isso tem imenso potencial para atrair a atenção dos estudantes; entretanto, ela é ainda mal explorada nos currículos das Escolas. Os dinossauros hollywoodianos são seres realmente fantásticos, mas desconectados da realidade dos nossos alunos, que geralmente desconhecem que o Brasil também teve seus dinossauros. Em virtude disso, o principal objetivo deste trabalho foi articular a área da Paleontologia com a Educação Básica, utilizando dinossauros brasileiros como tema central para a mediação de atividades didático pedagógicas com os alunos do Ensino Fundamental. O estudo se caracteriza como uma pesquisa bibliográfica de abordagem qualitativa, tendo sido realizado entre os anos de 2020 e 2023. O embasamento das atividades propostas utilizou a Base Nacional Comum Curricular (BNCC) e os dinossauros selecionados foram as espécies fósseis que ocorrem no Estado do Rio Grande do Sul (RS). O levantamento bibliográfico resultou na descoberta de 12 espécies de dinossauros, distribuídas em cinco cidades gaúchas, todas elas localizadas na região central do RS e pertencentes ao Período Triássico. A partir dos dados obtidos foram elaboradas e sugeridas atividades para quatro áreas da BNCC: linguagens, matemática, ciências da natureza e ciências humanas; a grande versatilidade da Paleontologia permitiu sua articulação com todas elas. Este trabalho pretende ser uma referência para professores que tenham interesse em buscar informações científicas mais aprofundadas sobre os dinossauros do RS, visando enriquecer o planejamento de suas aulas. Também espera estimular nos estudantes o interesse por ciências, a valorização do patrimônio paleontológico, e uma identidade com a Pré-história local.
... Most of these studies are based on specimens from Triassic beds of Southern Brazil. While the Brazilian Santa Maria Formation (lower portion of the Candel aria Sequence) has yielded some of the oldest dinosaurs worldwide (Colbert, 1970;Langer et al., 1999;Cabreira et al., 2016;Pacheco et al., 2019), the overlapping Caturrita Formation (upper portion of the Candel aria Sequence) has provided an important record of the immediate secondary step of dinosaur radiation (Bonaparte et al., 1999;Leal et al., 2004;Müller et al., 2018;Pinheiro, 2016). These deposits have provided insights on the anatomical and ecological evolution of dinosaurs that occurred along an ca 8 Ma interval, from 233.23 ± 0.73 Ma to 225.42 ± 0.37 Ma . ...
... So far, there are three distinct species of sauropodomorphs from the Caturrita Formation. The first described species was Guaibasaurus candelariensis (Bonaparte et al., 1999), which is known from at least four specimens (Langer et al., 2011). Unfortunately, no skull remains are known and there are some issues regarding its assignation to Sauropodomorpha, with some authors suggesting theropod affinities (Langer et al., 2011;Langer & Benton, 2006;Yates, 2007). ...
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The lineage of sauropodomorph dinosaurs raised some of the most impressive animals that ever walked on Earth. However, the massive titans of the Mesozoic Era originated from far smaller dinosaurs. The Triassic beds from Brazil yielded the earliest part of this evolutionary history. Despite the diverse fossil record of early sauropodomorphs, juvenile specimens, as well as certain species are poorly sampled. This is the case for Unaysaurus tolentinoi, an unaysaurid sauropodomorph from Caturrita Formation (ca. 225 Ma; early Norian, Late Triassic). The holotype and only specimen of U. tolentinoi was excavated from the Água Negra Locality (São Martinho da Serra, Rio Grande do Sul, Brazil) in 1998. More than two decades later, no other fossil vertebrates have been reported from the same fossiliferous site. Here we describe a skeletally immature specimen which was found in association with the holotype of U. tolentinoi. The specimen was discovered after a first-hand examination of the holotype and comprises some isolated vertebrae and elements from the posterior autopodium. According to linear regressions, its metatarsal I is approximately 41.7 mm in length, compared to approximately 75.9 mm in the holotype. The repeated elements and reduced size indicates that it does not belong to the elements originally used to erect U. tolentinoi. Rather, the specimen is assigned to U. tolentinoi by topotypy and shared morphology. In addition to the reduced size, distinct lines of evidence (e.g., neurocentral sutures; bone texture) support its assignment to a skeletally immature individual. In sum, the new material expands the record of U. tolentinoi, and represents an additional juvenile dinosaur from the Caturrita Formation.
... A 206Pb/238U date of 225.42 ± 0.37 Ma (Upper Triassic, Norian) was recovered for this site based on detrital zircon (Langer et al., 2018). It is characterized by massive, fine-grained sandstone beds and a typical Riograndia Assemblage Zone fauna, with small nonmammalian cynodonts, procolophonids, and lepidosaurs, as well as the dinosaur Guaibasaurus candelariensis (Bonaparte et al., 1999;Bonaparte et al., 2010;Soares et al., 2011). The Riograndia AZ represents the upper portion of the Candel aria Sequence (Horn et al., 2014) or the basal portion of the Caturrita Formation (Andreis et al., 1980;Schultz et al., 2000;Zerfass et al., 2003) of the Paran a Basin, previously known as Santa Maria Sequence II (Zerfass et al., 2003). ...
Article
Understanding the origins of the vertebrate brain is fundamental for uncovering evolutionary patterns in neuroanatomy. Regarding extinct species, the anatomy of the brain and other soft tissues housed in endocranial spaces can be approximated by casts of these cavities (endocasts). The neuroanatomical knowledge of Rhynchocephalia, a reptilian clade exceptionally diverse in the early Mesozoic, is restricted to the brain of its only living relative, Sphenodon punctatus, and unknown for fossil species. Here, we describe the endocast and the reptilian encephalization quotient (REQ) of the Triassic rhynchocephalian Clevosaurus brasiliensis and compare it with an ontogenetic series of S. punctatus. To better understand the informative potential of endocasts in Rhynchocephalia, we also examine the brain-endocast relationship in S. punctatus. We found that the brain occupies 30% of its cavity, but the latter recovers the general shape and length of the brain. The REQ of C. brasiliensis (0.27) is much lower than S. punctatus (0.84-1.16), with the tuatara being close to the mean for non-avian reptiles. The endocast of S. punctatus is dorsoventrally flexed and becomes more elongated throughout ontogeny. The endocast of C. brasiliensis is mostly unflexed and tubular, possibly representing a more plesiomorphic anatomy in relation to S. punctatus. Given the small size of C. brasiliensis, the main differences may result from allometric and heterochronic phenomena, consistent with suggestions that S. punctatus shows peramorphic anatomy compared to Mesozoic rhynchocephalians. Our results highlight a previously undocumented anatomical diversity among rhynchocephalians and provide a framework for future neuroanatomical comparisons among lepidosaurs.
... After an original suggestion by Bonaparte et al. (1999), Ezcurra (2010) proposed that the Norian dinosaur Guaibasaurus candelariensis nested, along with some Carnian taxa, into a clade of early sauropodomorphs named Guaibasauridae. In addition, Ezcurra (2010) proposed that Sat. ...
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Carnian (Late Triassic) deposits of South America provide the oldest unequivocal dinosaur records worldwide, most of which has been assigned to the sauropodomorph lineage. This includes Eoraptor lunensis, Panphagia protos, and Chromogisaurus novasi, from the Ischigualasto Formation, Argentina, and Saturnalia tupiniquim, Pampadromaeus barberenai, Buriolestes schultzi, and Bagualosaurus agudoensis, from the Santa Maria Formation, Brazil. Here, we demonstrate that their holotypes anatomically differ from one another, supporting the taxonomic validity of the species. In addition, a morphological disparity analysis, with significant statistical support, clustered some of the better-known specimens of E. lunensis, Sat. tupiniquim, and Bu. schultzi, with the respective holotypes. For the latter two taxa, this was corroborated by a specimen-level phylogenetic analysis that also found Ba. agudoensis as the sister taxon to post-Carnian sauropodomorphs. Our results also suggest that Bu. schultzi and E. lunensis are the earliest branching sauropodomorphs and that Sa. tupiniquim and Pam. barberenai are closer to Bagualosauria. A species-level phylogenetic analysis further suggests that Bu. schultzi and E. lunensis form a clade, that Sa. tupiniquim is the sister taxon to Bagualosauria, and that Pan. protos and Ch. novasi are also more highly nested, forming a clade with Pam. barberenai.
... Based on zircon U-Pb analyses, the maximum depositional age of the fossil-bearing layers is Norian at $225.42 ± 0.37 Mya (Langer et al. 2018). The Linha São Luiz outcrop has produced the procolophonian Soturnia caliodon (Cisneros & Schultz 2003), the rhynchocephalians Clevosaurus brasiliensis (Bonaparte & Sues 2006) and Lanceirosphenodon ferigoloi (Romo de Vivar et al. 2020a), the non-rhynchocephalian lepidosauromorph Cargninia enigmatica (Bonaparte et al. 2010;Romo de Vivar et al. 2020b), an archosaur of uncertain affinities, Faxinalipterus minima (Bonaparte et al. 2010;Soares et al. 2013), the dinosaur Guaibasaurus candelariensis (Bonaparte et al. 1999(Bonaparte et al. , 2007, and the probainognathian cynodonts Brasilodon quadrangularis (¼ Brasilitherium riograndensis, Minicynodon maieri), Riograndia guaibensis and Irajatherium hernandezi (e.g. Bonaparte et al. 2001Bonaparte et al. , 2003Bonaparte et al. , 2005Bonaparte et al. , 2010Bonaparte et al. , 2012Martinelli et al. 2005Martinelli et al. , 2017Oliveira et al. 2011;Soares et al. 2011). ...
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Rhynchocephalians are a group of lizard-like diapsid reptiles that were very diverse during the Mesozoic but are now restricted to a single extant genus in New Zealand. Recent cladistic analyses have revealed two major clades, Eusphenodontia and the more crownward Neosphenodontia, but relationships of individual taxa have remained difficult to determine because of missing data and an unrevised data matrix. Here we drastically revise the established data matrix on rhynchocephalians by reassessing, evaluating, and adding new characters and operational taxonomic units, differing from any previous analyses in our goal to consider all known rhynchocephalians. In addition, we describe a new genus and species of an early eusphenodontian taxon from the Norian of southern Brazil, with a unique mosaic of plesiomorphic and apomorphic traits, and we re-examine the craniodental anatomy of the eusphenodontian Clevosaurus brasiliensis with µCT imaging, revealing a unique form of acrodonty amongst rhynchocephalians. http://zoobank.org/urn:lsid:zoobank.org:pub:A9211C5A-D4F9-472A-B8AB-877D13ABFDD5
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The Carnian (Upper Triassic) rocks of the Candelária Sequence present a rich record of dinosaurs, including some of the oldest known dinosaurs worldwide. In this contribution we describe the first unequivocal dinosaur from the Pivetta site, located in the Restinga Sêca municipality, Southern Brazil. The specimen CAPPA/UFSM 0373 is an isolated but well-preserved left ilium. A thorough examination of the specimen's anatomy and a phylogenetic analysis provides evidence that CAPPA/UFSM 0373 belongs to the Herrerasauria. We were able to identify several similarities with potential non-herrerasaurid herrerasaurians (e.g., Tawa hallae, "Caseosaurus crosbyensis"), which were previously only known from North American deposits. In contrast, herrerasaurids (e.g., Herrerasaurus ischigualastensis) are almost exclusively known from South America. Our results support the nesting of CAPPA/UFSM 0373 as an early-diverging herrerasaurian. Furthermore, this is potentially the first record of a non-herrerasaurid herrerasaurian in unambiguous Carnian beds, suggesting a hidden diversity of dinosaurs in the Carnian rocks of the Candelária Sequence, which can be revealed even by fragmentary specimens.
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Faxinalipterus minimus was originally described as a purported pterosaur from the Late Triassic (early Norian) Caturrita Formation of southern Brazil. Its holotype comprises fragmentary postcranial elements, whereas a partial maxilla was referred to the species. The assignment of Faxinalipterus minimus to Pterosauria has been questioned by some studies, but the specimen has never been accessed in detail after its original description. Here we provide a reassessment of Faxinalipterus minimus after additional mechanical preparation of the holotype. Our interpretations on the identity of several bones differ from those of the original description, and we found no support favoring pterosaur affinities for the taxon. The maxilla previously referred to Faxinalipterus minimus is disassociated from this taxon and referred to a new putative pterosauromorph described here from a partial skull and fragmentary postcranial elements. Maehary bonapartei gen. et sp. nov. comes from the same fossiliferous site that yielded Faxinalipterus minimus, but the lack of overlapping bones hampers comparisons between the two taxa. Our phylogenetic analysis places Faxinalipterus minimus within Lagerpetidae and Maehary bonapartei gen. et sp. nov. as the earliest-diverging member of Pterosauromorpha. Furthermore, the peculiar morphology of the new taxon reveals a new dental morphotype for archosaurs, characterized by conical, unserrated crowns, with a pair of apicobasally oriented grooves. These two enigmatic archosaurs expand our knowledge on the Caturrita Formation fauna and reinforce the importance of its beds on the understanding of Late Triassic ecosystems.
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