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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.

BACKGROUND: We report the discovery of a nematode parasite egg (Nemata: Oxyurida) from a coprolite closely associated with the remains of several species of Cynodontia, dated to 240 million years old. This finding is particularly significant because this is the oldest record of an oxyurid nematode yet discovered, and because the cynodonts are considered a stem-group of the mammals. METHODS: We extracted material from a fully mineralized coprolite by both scraping the surface, and removing fragments from its interior with clean dental instruments used a single time. A single drop of glycerol from a new vial was added as a clearing reagent. Each slide was sealed with wax and examined with an optical microscope at 100× to 400× magnification. RESULTS: From one coprolite, 550 slides were examined; from 275 of these slides, sediment was examined that was scraped from the surface of the coprolite, and from the other 275 slides, material was examined that was extracted from the interior of the coprolite. All microscopic structures encountered were photographed, measured, and identified when possible. CONCLUSIONS: From the coprolite examined, we discovered an egg representing a new species of pinworm that, based on the egg structure, clearly places it in the family Heteroxynematidae. Nematodes of the order Oxyurida have very constrained life-histories, occurring only in animals that are not strictly carnivorous and also ingest large amounts of plant material. This fact enabled us to determine which species of cynodont, from several collected at the site in Brazil, are most likely the depositors of the coprolite, and therefore were the putative host of the parasite.

The first record of palaeo-wildfire evidence in the form of charcoal is documented from the Late Permian Zewan Formation of the Kashmir region, northwest Himalaya. This evidence is in the form of fragments of tracheids that show homogenized cell walls, a characteristic feature of charcoal. Considering that palaeo-wildfire studies provide important palaeoecological information, the present study is significant, as it allows reconstructing new information about environmental conditions during the deposition of the sediments of the Late Permian Zewan Formation.

After the Permo-Triassic mass extinction, the archosauromorph fossil record is comparatively abundant and ecologically diverse. Among early archosauromorphs, tanystropheids gained considerable attention due to the presence of extreme skeletal adaptations in response to sometimes overspecialized lifestyles. The origin and early radiation of Tanystropheidae, however, remains elusive. Here, a new Early Triassic archosauromorph is described and phylogenetically recovered as the sister-taxon of Tanystropheidae. The new specimen, considered a new genus and species, comprises a complete posterior limb articulated with pelvic elements. It was recovered from the Sanga do Cabral Formation (Sanga do Cabral Supersequence, Lower Triassic of the Paraná Basin, Southern Brazil), which has already yielded a typical Early Triassic vertebrate assemblage of temnospondyls, procolophonoids, and scarce archosauromorph remains. This new taxon provides insights on the early diversification of tanystropheids and represents further evidence for a premature wide geographical distribution of this clade. The morphology of the new specimen is consistent with a terrestrial lifestyle, suggesting that this condition was plesiomorphic for Tanystropheidae.

[This corrects the article DOI: 10.1371/journal.pone.0230890.].

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.

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.

The fossiliferous sites from Santa Maria are known since thebeginning of the XX century, being recorded fossil vertebrates, invertebratesand plant remains from the Late Triassic. However, this patrimony needs to beprotected, being the lack of governmental action a main risk to depredation inmost cases. In this paper, the fossiliferous sites from the urban area of SantaMaria, South of Brazil, are recognized, in order to help in their protection.