Ane Elise Branco Pavanatto

A new fossiliferous site from the Pinheiros-Chiniquá Sequence (Santa Maria Supersequence) with typical tetrapod components of the Dinodontosaurus Assemblage Zone (AZ) is here described. The new site is included in the Faxinal do Soturno Structural Block. The fossil content is characterized by cranial and postcranial material of rauisuchian archosaurs, traversodontid and chiniquodontid cynodonts and dicynodonts, the first occurrence of a large-sized coelacanth fish in the Brazilian Triassic, as well as ichnological material, represented by coprolites. The presence of Luangwa together with Massetognathus raises interesting questions regarding the age of this site included in the Dinodontosaurus AZ when compared with other localities of Southern Brazil, western Argentina and Africa. As in other localities of this AZ, the fossil specimens recovered in Bortolin site exhibit remarkable differences on their fossil preservation: those from the lower portion of the outcrop (distal floodplain) possess a heterogeneous preservation (variable between poor to fairly good) whereas those from the top levels (proximal floodplain) are comparatively better preserved. This new locality, with a large amount of stratigraphically controlled fossils, constitutes a key-locality to study the distribution of Triassic terrestrial tetrapods and to perform comparisons with other sites of this AZ, inwhich several historical records lack a precise provenance. Keywords: Dinodontosaurus Assemblage Zone, Santa Maria Supersequence, Luangwa, coelacanth. Um novo sítio fossilífero é descrito para a Sequência Pinheiros-Chiniquá (Supersequência Santa Maria) com tetrápodes típicos da Zona de Associação (ZA) de Dinodontosaurus. Este novo sítio está incluído no Bloco Estrutural Faxinal do Soturno. O conteúdo fóssil é caracterizado por materiais cranianos e pós-cranianos de arcossauros rauissuquídeos, cinodontes chiniquodontídeos e traversodontídeos e dicinodontes, a primeira ocorrência de um peixe celacanto de grande tamanho, além de materiais icnológicos, representados por coprólitos. A presença de Luangwa juntamente com Massetognathus levanta interessantes questões acerca da idade desse sítio, incluído na ZA de Dinodontosaurus, quando comparado com outras localidades do sul do Brasil, oeste da Argentina e África. Assim como em outras localidades desta ZA, os espécimes fósseis coletados no sítio Bortolin apresentam diferenças notáveis na preservação dos fósseis: fósseis do nível inferior do afloramento (planície de inundação distal) apresentam preservação heterogênea (variando entre pobre a razoavelmente bem preservado) enquanto que nos níveis superiores (planície de inundação proximal), o registro fóssil é comparativamente melhor preservado. Esta nova localidade, com uma grande quantidade de fósseis estratigraficamente controlados, constitui uma localidade chave para o estudo da distribuição dos tetrápodes terrestres do Triássico e sua comparação com outros sítios desta ZA, na qual vários registros históricos carecem de uma proveniência precisa. Palavras-chave: Zona de Associação de Dinodontosaurus, Supersequência Santa Maria, Luangwa, celacanto. A new fossiliferous site from the Pinheiros-Chiniquá Sequence (Santa Maria Supersequence) with typical tetrapod components of the Dinodontosaurus Assemblage Zone (AZ) is here described. The new site is included in the Faxinal do Soturno Structural Block. The fossil content is characterized by cranial and postcranial material of rauisuchian archosaurs, traversodontid and chiniquodontid cynodonts and dicynodonts, the first occurrence of a large-sized coelacanth fish in the Brazilian Triassic, as well as ichnological material, represented by coprolites. The presence of Luangwa together with Massetognathus raises interesting questions regarding the age of this site included in the Dinodontosaurus AZ when compared with other localities of Southern Brazil, western Argentina and Africa. As in other localities of this AZ, the fossil specimens recovered in Bortolin site exhibit remarkable differences on their fossil preservation: those from the lower portion of the outcrop (distal floodplain) possess a heterogeneous preservation (variable between poor to fairly good) whereas those from the top levels (proximal floodplain) are comparatively better preserved. This new locality, with a large amount of stratigraphically controlled fossils, constitutes a key-locality to study the distribution of Triassic terrestrial tetrapods and to perform comparisons with other sites of this AZ, inwhich several historical records lack a precise provenance. Keywords: Dinodontosaurus Assemblage Zone, Santa Maria Supersequence, Luangwa, coelacanth. Um novo sítio fossilífero é descrito para a Sequência Pinheiros-Chiniquá (Supersequência Santa Maria) com tetrápodes típicos da Zona de Associação (ZA) de Dinodontosaurus. Este novo sítio está incluído no Bloco Estrutural Faxinal do Soturno. O conteúdo fóssil é caracterizado por materiais cranianos e pós-cranianos de arcossauros rauissuquídeos, cinodontes chiniquodontídeos e traversodontídeos e dicinodontes, a primeira ocorrência de um peixe celacanto de grande tamanho, além de materiais icnológicos, representados por coprólitos. A presença de Luangwa juntamente com Massetognathus levanta interessantes questões acerca da idade desse sítio, incluído na ZA de Dinodontosaurus, quando comparado com outras localidades do sul do Brasil, oeste da Argentina e África. Assim como em outras localidades desta...

The brain endocasts of the late Triassic (Carnian) traversodontids (Eucynodontia: Gomphodontia) Siriusgnathus niemeyerorum and Exaeretodon riograndensis from southern Brazil are described based on virtual models generated using computed tomography scan data. Their skull anatomy resembles that of other non‐mammaliaform cynodonts, showing an endocranial cavity that is not fully ossified. A “V‐shaped” orbitosphenoid, neither fully developed nor ossified is present in E. riograndensis. The nasal cavity is confluent with the encephalic cavity. Thus, the anterior limit of the olfactory bulbs is not definite. The brain endocast is elongated, being narrow anteriorly and wide posteriorly, with the maximum width at the parafloccular cast. The olfactory bulbs do not present a clear division between their counterparts, due to the absence of a longitudinal sulcus. A longitudinal sulcus in the forebrain delimiting the cerebral hemispheres, the pineal tube, and the parietal foramen are absent in both taxa. The large and well‐developed unossified zone is partially separated from the remaining endocast by a notch formed by the supraoccipital. The encephalization quotients, as well as the endocranial volume/body mass relationships of S. niemeyerorum and E. riograndensis are within the range expected for non‐mammaliaform Therapsida.

New postcranial remains of Massetognathus ochagaviae are described based on a new specimen collected at the Dinodontosaurus Assemblage Zone from the Middle Triassic of Southern Brazil. Several isolated teeth collected together with the postcranial skeleton allowed a taxonomic assignation of the specimen to M. ochagaviae. Its postcranial morphology is quite similar to Massetognathus pascuali, especially regarding the morphology of the transverse process of presacral vertebrae (i.e. laminar in the anterior most and rounded in the posterior most presacral vertebrae); humerus (i.e. the head is dorsally deflected with a ‘fan-shaped’ distal end a deltopectoral crest abruptly ending at the middle of shaft); and femur (with a bulbous and dorsomedially inclined femoral head, lesser trochanter which abruptly begins near the intertrochanteric fossa and extending up to the middle of the femoral shaft and the medial condyle more pronounced and ventrally projected than the lateral one). On the other hand, the clavicle of M. ochagaviae is less lateromedially elongated than in M. pascuali.