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Dinosaur fossils are commonly found in Brazilian Mesozoic strata, with teeth being frequently found in Cretaceous outcrops. Many studies have been made with the aim of reviewing the known diversity of Brazilian dinosaurs, mostly focusing solely on their palaeobiogeography. However, few tried to typify these body fossils in order to see which kinds were most prevalent in the fossil record. This study aims to count and identify all occurrences of non-avian dinosaur teeth (isolated or in situ) unearthed from Brazilian Cretaceous strata in order to objectively measure their representativity in the national fossil record. Our literature search showed that almost half of the dinosaur fossil record from the Cretaceous of Brazil is composed by teeth, those being particularly abundant in the Alcântara, Adamantina and Marília formations. Theropod teeth are more abundant in comparison to sauropod teeth, with spinosaurids, deinonychosaurs, and abelisaurids being amply found. Despite representing a large share of the Brazilian fossil record, dinosaur teeth have only recently been studied in depth, with many specimens being reassessed through the current identification methods. Other aspects besides primary taxonomic identification can also be further explored using the latest technologies on dinosaur teeth, allowing a deeper understanding of the palaeobiology of these reptiles. [ABSTRACT FROM AUTHOR]

The digital reconstruction of neurocranial endocasts has elucidated the gross brain structure and potential ecological attributes of many fossil taxa, including Irritator, a spinosaurine spinosaurid from the "mid" Cretaceous (Aptian) of Brazil. With unexceptional hearing capabilities, this taxon was inferred to integrate rapid and controlled pitch‐down movements of the head that perhaps aided in the predation of small and agile prey such as fish. However, the neuroanatomy of baryonychine spinosaurids remains to be described, and potentially informs on the condition of early spinosaurids. Using micro‐computed tomographic scanning (μCT), we reconstruct the braincase endocasts of Baryonyx walkeri and Ceratosuchops inferodios from the Wealden Supergroup (Lower Cretaceous) of England. We show that the gross endocranial morphology is similar to other non‐maniraptoriform theropods, and corroborates previous observations of overall endocranial conservatism amongst more basal theropods. Several differences of unknown taxonomic utility are noted between the pair. Baryonychine neurosensory capabilities include low‐frequency hearing and unexceptional olfaction, whilst the differing morphology of the floccular lobe tentatively suggests less developed gaze stabilisation mechanisms relative to spinosaurines. Given the morphological similarities observed with other basal tetanurans, baryonychines likely possessed comparable behavioural sophistication, suggesting that the transition from terrestrial hypercarnivorous ancestors to semi‐aquatic "generalists" during the evolution of Spinosauridae did not require substantial modification of the brain and sensory systems. [ABSTRACT FROM AUTHOR]

The origin of the air sac system present in birds has been an enigma for decades. Skeletal pneumaticity related to an air sac system is present in both derived non-avian dinosaurs and pterosaurs. But the question remained open whether this was a shared trait present in the common avemetatarsalian ancestor. We analyzed three taxa from the Late Triassic of South Brazil, which are some of the oldest representatives of this clade (233.23 ± 0.73 Ma), including two sauropodomorphs and one herrerasaurid. All three taxa present shallow lateral fossae in the centra of their presacral vertebrae. Foramina are present in many of the fossae but at diminutive sizes consistent with neurovascular rather than pneumatic origin. Micro-tomography reveals a chaotic architecture of dense apneumatic bone tissue in all three taxa. The early sauropodomorphs showed more complex vascularity, which possibly served as the framework for the future camerate and camellate pneumatic structures of more derived saurischians. Finally, the evidence of the absence of postcranial skeletal pneumaticity in the oldest dinosaurs contradicts the homology hypothesis for an invasive diverticula system and suggests that this trait evolved independently at least 3 times in pterosaurs, theropods, and sauropodomorphs. [ABSTRACT FROM AUTHOR]

Dinosaur fossils are becoming increasingly well-known from the Bauru Basin of Brazil, and represent some of the last occurring dinosaurs in South America before the end-Cretaceous mass extinction. However, sampling across the basin is not uniform, and comparatively little is known about the fossils from the northern part of the basin. Our fieldwork team discovered two isolated and well-preserved ziphodont theropod teeth from northern basin strata of the Maastrichtian Marília Formation of the south of the state of Goiás. We here identify them using quantitative analysis of morphometric data and comparisons to teeth previously described in the literature. Our comparisons and analyses indicate that they can be assigned to Abelisauridae. These specimens have little evident crown enamel ornamentation, a characteristic widely present in the teeth of theropods from the Southern Hemisphere. The materials described here are the northernmost Bauru Basin abelisaurids reported so far, demonstrating that these carnivorous dinosaurs were important faunal components across the extent of the basin, as they were in other regions of South America. • This study presents a first Abelisauridae records from the from state of Goiás of Late Cretaceous Bauru Group. • The Upper Cretaceous Abelisauridae from South America were expanded into a new area. [ABSTRACT FROM AUTHOR]

Some new tridactyl footprints have been recorded in the Malhada Vermelha farm locality, municipality of Fortaleza dos Nogueiras, state of Maranhão, northern Brazil, from the Sambaíba Formation, Parnaíba Sedimentary Basin. The specimens are fifteen isolated, in situ, mesaxonic tridactyl tracks preserved in six sandstone slabs as concave epireliefs. Abundant MISS evidence is preserved in the track-bearing blocks. The footprints are referred to as Grallator isp., linking them with an theropodian origin. The footprint-bearing levels were accumulated in shallow environments influenced by a tidal flat. The occurrence and interpretation of these findings bring a new approach to sedimentary subenvironments in the Sambaíba Formation. • Ichnofossils consisting of tridactyl footprints were found in the Sambaíba Formation, attributed to sedimentation in an arid climate. • All the track-bearing surfaces in the slabs or blocks have abundant evidence of microbially induced sedimentary structures. • The general features of the tracks presented herein allow to link their producer with Theropoda. • The analysis of the Sambaíba Sandstone outcropping in the study area allows us to consider the occurrence of marine incursions in that region of the basin during the late Triassic and early Jurassic. [ABSTRACT FROM AUTHOR]

Ichnofossils are a useful tool in determining some aspects of the palaeoecology from past ecosystems, being often used as evidence of interactions between extinct organisms. In this paper we describe tooth traces found in UFRJ-DG 705 R, a fragmentary sauropod epiphysis, from the Presidente Prudente Formation, Bauru Group. We infer that these traces were made by a small to medium-sized crocodyliform, most likely an itasuchid, in a possible act of necrophagy. This new record of tooth traces in the Bauru Group showcases important evidence concerning trophic relations between sauropods and crocodyliforms in this locality during the Late Cretaceous. [ABSTRACT FROM AUTHOR]

The description of new titanosaur specimens unearthed from deposits of the Serra da Galga Formation (Bauru Group, Late Cretaceous) at the BR-262 site, near Peirópolis (Uberaba, Minas Gerais State, Brazil), sheds light on the taxonomy of two taxa previously known from the same area and geological unit: Baurutitan britoi and Trigonosaurus pricei. A comparative revision indicates that T. pricei represents a junior synonym of Ba. britoi, and that the BR-262 specimens belong to that latter species. The information provided by the new specimens also revealed that the paratype of T. pricei (MCT 1719-R), a caudal vertebral series, actually represents a new taxon, named here as Caieiria allocaudata gen. et sp. nov. [ABSTRACT FROM AUTHOR]

Despite being poorly known from limited skeletal remains as teeth and a few postcranial material, spinosaurid remains have been reported from two different Lower Cretaceous localities in Brazil, with three officially proposed taxa up to now: Angaturama, Irritator and Oxalaia. Here, we report the first record of a spinosaurid pedal ungual from the Itapecuru Formation, Parnaíba Basin, Lower Cretaceous rocks of Maranhão State. The specimen retains a quite flat ventral surface that is proportionally almost two times broader than its proximal depth, which is a feature also found in Spinosaurus. Moreover, size inferences are made for this immature specimen. [ABSTRACT FROM AUTHOR]

The Vila Botucaraí site is located west of the municipality of Candelária, Rio Grande do Sul State, southern Brazil, and is particularly important because it represents the type locality of the species Exaeretodon riograndensis (Cynodontia, Traversodontidae), Charruodon tetracuspidatus (Cynodontia, Probainognathia) and Proterochampsa nodosa (Archosauriformes, Proterochampsidae). The site is correlated to the Hyperodapedon Assemblage Zone whose fossiliferous content allows to correlate it to the lower half of the Ischigualasto Formation (Ischigualasto-Villa Unión Basin), of late Carnian age, in Argentina. The aim of this study is to record the first remains of dinosaurs from this locality, found in 2001 during the Pró-Guaiba Project and stored in the Scientific Collection of the Paleontology Section of the Museu de Ciências Naturais, Secretaria Estadual do Meio Ambiente e Infraestrutura, Porto Alegre, RS. In addition to the taxa mentioned at the Vila Botucaraí site, the archosauromorph Hyperodapedon sp. was also preliminarily recorded. The Dinosauria specimen includes four dorsal vertebrae (MCN-PV 10347a, b, c, d). The general characteristics observed are: (i) absence of a ventral keel in the vertebral centra, shared with Guaibasaurus , Bagualosaurus , Pampadromaeus ; (ii) amphicoelic centra with concave ventral surface, shared with Bagualosaurus , Guaibasaurus , and most non-sauropod sauropodomorphs (exceptions are, for example, Riojasaurus ; also, this character does not appear in herrerasaurids); (iii) vertebral laminae connected to the diapophysis, and their arrangement results in different fossae, as in Bagualosaurus , Buriolestes , Guaibasaurus , and herrerasaurids; (iv) neural spine anteroposteriorly elongated and transversely narrow, as in Bagualosaurus , Pampadromaeus , Buriolestes , Macrocollum , differing from herrerasaurids and theropods. This set of characters is similar to that observed in basal sauropodomorphs, quite different from the neural spine with a spine table, such as the observed in herrerasaurids. Specimen MCN-PV 10347 is here considered a member of the Sauropodomorpha clade and tentatively identified as cf. Bagualosauria. The features of this specimen are shared among Carnian (e.g., Buriolestes schultzi , Bagualosaurus agudoensis) and Norian (e.g., Unaysaurus tolentinoi , Guaibasaurus candelariensis) sauropodomorphs. In addition to this, the new material expands the knowledge regarding the number of outcrops with the occurrence of sauropodomorphs for the Triassic in Brazil, as well as about the paleofauna of the Vila Botucaraí site, allowing us to infer its biostratigraphic correlation with one of the sub-divisions already proposed for the Hyperodapedon AZ, the Exaeretodon Subzone, interpreted as the top of this AZ. Despite the abundance of sauropodomorphs in Rio Grande do Sul, this record confirms the occurrence of this clade at the Hyperodapedon AZ in the Candelária region. • Taxonomic analysis of the dorsal vertebrae of a non-sauropod sauropodomorph. • The correlations of coeval extracts within the of Hyperodapedon AZ. • First record of a dinosaur cf. Bagualosauria outside the locality -type of Bagualosaurus agudoensis. [ABSTRACT FROM AUTHOR]

Aeolosaurus is a late Cretaceous Titanosaur genus with two species discovered in Argentina and one in Brazil. Although the allocation of the Argentinean Aeolosaurus seems unequivocal, that is not the case for the Brazilian species Aeolosaurus maximus since several authors questioned its positioning into this genus, based on both anatomical and phylogenetic data. The revision of the diagnosis of Ae. maximus, with the proposition of a new autapomorphy, corroborates the anatomical uniqueness and our phylogenetic analysis stresses that the relation of Ae. maximus to the Argentinean Aeolosaurus is uncertain. Based upon that, we propose a new genus, Arrudatitan, to accommodate the Brazilian taxon. [ABSTRACT FROM AUTHOR]

The recognition of ontogenetic edentulism in the Jurassic noasaurid Limusaurus inextricabilis shed new light on the dietary diversity within Ceratosauria, a stem lineage of non-avian theropod dinosaurs known for peculiar craniomandibular adaptations. Until now, edentulism in Ceratosauria was exclusive to adult individuals of Limusaurus. Here, an exceptionally complete skeleton of a new toothless ceratosaur, Berthasaura leopoldinae gen. et sp. nov., is described from the Cretaceous aeolian sandstones of the Bauru Basin, Southern Brazil. The specimen resembles adult individuals of Limusaurus by the absence of teeth but based on the unfused condition of several elements (e.g., skull, vertebral column) it clearly represents an ontogenetically immature individual, indicating that it might never have had teeth. The phylogenetic analysis performed here has nested Berthasaura leopoldinae as an early-divergent Noasauridae, not closely related to Limusaurus. It represents the most complete non-avian theropod from the Brazilian Cretaceous and preserves the most complete noasaurid axial series known so far. Moreover, the new taxon exhibits many novel osteological features, uncommon in non-avian theropods, and unprecedented even among South American ceratosaurs. These include not only toothless jaws but also a premaxilla with cutting occlusal edge, and a slightly downturned rostral tip. This indicate that B. leopoldinae unlikely had the same diet as other ceratosaurs, most being regarded as carnivorous. As the ontogenetically more mature specimens of Limusaurus, Berthasaura might have been herbivorous or at least omnivorous, corroborating with an early evolutionary divergence of noasaurids from the ceratosaurian bauplan by disparate feeding modes. [ABSTRACT FROM AUTHOR]

The record of unenlagiines in Brazil, except for one dorsal vertebra, is still under debate based on isolated teeth. Here, we describe Ypupiara lopai gen. et sp. nov., the first dromaeosaurid species from Brazil, from the Maastrichtian of the Bauru Group, Paraná Basin. The specimen consists of a partial right maxilla (with three teeth in loci) and a right dentary. Ypupiara is characterized by a restricted number of neurovascular foramina on the lateral surface of the maxilla, a rectangular and anteroposteriorly expanded interdental plate, and a labiolingual compression of the teeth, which have a labiolingual diameter more than 3/5 of the rostrocaudal diameter. Our phylogenetic analysis recovers Ypupiara as an unenlagiine based on the fluted teeth and places it as the sister taxon of Austroraptor due to the ratio of the labiolingual and mesiodistal diameters of the teeth being more than 3/5. We also erect the new group Unenlagiinia, which includes Unenlagiinae and Halszkaraptorinae. Ypupiara nests within Unenlagiinia based on the widely spaced teeth and the lack of mesial and distal carinae in the maxillary teeth. The morphology of the teeth is similar to Buitreraptor, although the proportions are markedly distinct. The teeth and comparisons with other Unenlagiinia also support fish being part of the diet for Ypupiara. We also performed a parsimony analysis of endemicity, which suggested that the presence of unenlagiines in Brazilian Upper Cretaceous outcrops is explained by dispersion or extinction events. The new species provides new information on the evolution of Gondwanan dromaeosaurids, and its preserved teeth provide new data to enable the assignment of isolated dromaeosaurid teeth from the Bauru Group. [ABSTRACT FROM AUTHOR]

The morphology of the ankle is a crucial topic towards our understanding of the evolutionary history of Archosauria. The morphology of these bones is directly correlated with posture, and subsequently this provides an important phylogenetic signal. The astragalar anatomy is widely adopted in phylogenetic studies of dinosaurs, however, this bone is largely missing from some of our geologically oldest dinosaurian specimens. This is the case for Buriolestes schultzi, an early sauropodomorph from the Upper Triassic (Carnian) of southern Brazil. Here, a new astragalus is reported from the type locality of B. schultzi. The presence of a markedly rimmed and elliptical fossa posterior to the anterior ascending process corroborates saurischian affinities for this new specimen. Moreover, the short anteromedial corner of the element differs from that of several other post-Carnian sauropodomorphs. Additionally, the absence of the astragalar posterior crest in this specimen also differentiates it from several theropods. Unfortunately, there are no autapomorphic traits that support a reliable alpha taxonomic assignation. Therefore, the specimen in question cannot be positively assigned to B. schultzi. Conversely, there are no significant differences between the new specimen and B. schultzi, which could alternatively be supportive of a taxonomic assignment based on topotypical principles. [ABSTRACT FROM AUTHOR]

The first chondrichthyan teeth, dermal and oropharyngeal denticles from the Lower Cretaceous lacustrine Quiricó Formation (Sanfranciscana Basin), in southeastern Brazil are described. Eight microremains morphologies have been recovered from lower levels of this formation, dated as possibly Valanginian with basis on ostracods. The dermal denticles belongs to indeterminate Hybodontiformes; some teeth are ascribed to ?Lonchidiidae. The presence of Tribodus is suggested by some dermal denticles, but this assignment requires confirmation with more complete material. The new specimens indicate a much greater diversity of chondrichthyans in the Quiricó Formation than previously thought. The associated occurrence of hybodontiforms, the coelacanthiform Mawsonia and early neopterygians observed in the Sanfranciscana Basin is not uncommon for the Cretaceous sedimentary strata of Brazil and Africa. However, the use of the Quiricó Formation shark remains as biostratigraphic tool is limited, due to their current poor taxonomic and relatively broad temporal distribution. [ABSTRACT FROM AUTHOR]

The fusion of the sacrum occurs in the major dinosaur lineages, i.e. ornithischians, theropods, and sauropodomorphs, but it is unclear if this trait is a common ancestral condition, or if it evolved independently in each lineage, or even how or if it is related to ontogeny. In addition, the order in which the different structures of the sacrum are fused, as well as the causes that lead to this co‐ossification, are poorly understood. Herein, we described the oldest record of fused sacral vertebrae within dinosaurs, based on two primordial sacral vertebrae from the Late Triassic of Candelária Sequence, southern Brazil. We used computed microtomography (micro‐CT) to analyze the extent of vertebral fusion, which revealed that it occurred only between the centra. We also assessed the occurrence of sacral fusion in Dinosauria and close relatives. The degree of fusion observed in representatives of the major dinosaur lineages suggested that there may be a sequential pattern of fusion of the elements of the sacrum, more clearly observed in Sauropodomorpha. Our analyses suggest that primordial sacral vertebrae fuse earlier in the lineage (as seen in Norian sauropodomorphs). Intervertebral fusion is observed to encompass progressively more vertebral units as sauropodomorphs evolve, reaching up to five or more fully fused sacrals in Neosauropoda. Furthermore, the new specimen described here indicates that the fusion of sacral elements occurred early in the evolution of dinosaurs. Factors such as ontogeny and the increase in body size, combined with the incorporation of vertebrae to the sacrum may have a significant role in the process and in the variation of sacral fusion observed. [ABSTRACT FROM AUTHOR]

Our knowledge on the anatomy of the first dinosaurs (Late Triassic, 235–205 Ma) has drastically increased in the last years, mainly due to several new findings of exceptionally well‐preserved specimens. Nevertheless, some structures such as the neurocranium and its associated structures (brain, labyrinth, cranial nerves, and vasculature) remain poorly known, especially due to the lack of specimens preserving a complete and articulated neurocranium. This study helps to fill this gap by investigating the endocranial cavity of one of the earliest sauropodomorphs, Buriolestes schultzi, from the Upper Triassic (Carnian—c. 233 Ma) of Brazil. The endocranial anatomy of this animal sheds light on the ancestral condition of the brain of sauropodomorphs, revealing an elongated olfactory tract combined to a relatively small pituitary gland and well‐developed flocculus of the cerebellum. These traits change drastically across the evolutionary history of sauropodomorphs, reaching the opposite morphology in Jurassic times. Furthermore, we present here the first calculations of the Reptile Encephalization Quotient (REQ) for a Triassic dinosaur. The REQ of B. schultzi is lower than that of Jurassic theropods, but higher than that of later sauropodomorphs. The combination of cerebral, dental, and postcranial data suggest that B. schultzi was an active small predator, able to track moving prey. [ABSTRACT FROM AUTHOR]

Upper Triassic (Carnian) strata from the Candelária Sequence of southern Brazil bear the oldest records of dinosaurs worldwide. In consequence, investigation of the specimens yielded by these fossiliferous units is crucial for a more comprehensive knowledge regarding the origin, early diversification and radiation of dinosaurs. Herein we reassess a dinosaur specimen from Brazil, informally known as the 'Big Saturnalia', a supposed large-sized sauropodomorph unearthed at the 'Cerro da Alemoa' locality in Santa Maria municipality, Rio Grande do Sul State. However, our phylogenetic analyses and comparisons of the known elements of this specimen resulted in herrerasaurid affinities instead. In fact, it is the largest specimen so far of a herrerasaurid from the Candelária Sequence. It preserves cranial and postcranial elements, with the former being unprecedented for dinosaurs from the Alemoa local fauna. The morphology of the specimen allows new insights into the anatomy, evolution and distribution of some character states among Herrerasauridae, including but not limited to the typical craniocaudally short caudal dorsal vertebrae. Moreover, the specimen adds to the dinosauromorph diversity in the Carnian units of southern Brazil and its large size provides further support for herrerasaurids as top-tier predators during the dawn of dinosaurs in south-western Pangaea. [ABSTRACT FROM AUTHOR]

Buriolestes schultzi is a small sauropodomorph dinosaur from Carnian beds (ca., 233 Ma) of southern Brazil. It is one of the earliest members of that lineage and is a key taxon to investigate the initial evolution of Sauropodomorpha. Here, we attribute a new specimen to B. schultzi from Late Triassic of southern Brazil, which represents the first occurrence of the taxon outside the type locality. The new specimen comprises a disarticulated and partial skeleton, including cranial and postcranial elements. It is tentatively regarded as an additional specimen of B. schultzi according to a unique combination of traits (including autapomorphies). Conversely, the new specimen is stouter than the other specimens of B. schultzi, as shown by femoral Robustness Index. Based on femoral circumference, the estimated body mass of the new specimen is approximately 15 kg, which is far higher than the previous estimations for other specimens of B. schultzi (i.e., approximately 7 kg). In fact, the new specimen and some specimens of Eoraptor lunensis and Saturnalia tupiniquim were found to be significantly stouter than coeval sauropodomorphs. Therefore, instead of all being constructed as gracile, the earliest sauropodomorphs experienced an unappreciated intraspecific variation in robustness. This is interesting because more precise data on species body mass are crucial in order to better understand the complex terrestrial ecosystems in which dinosaurs originated., (© 2023 American Association for Anatomy.)

Discoveries from South America have increased our knowledge on the early evolutionary history of sauropodomorph dinosaurs. The dietary shift from faunivorous to herbivorous creatures and the increasing body size are both widely documented in the fossil record. Conversely, the initial evolution of the elongated neck is poorly known. It is one of the most diagnostic features of Sauropodomorpha. There is a gap between the record of short-necked sauropodomorphs from Carnian (±233 Ma) and long-necked forms from early Norian (±225 Ma). As a consequence, it is unknown if the cervical vertebrae became long gradually or abruptly. In the present study, we present a new specimen excavated from strata that belong to this time interval (±228 Ma). CAPPA/UFSM 0352 comprises a series of five cervical vertebrae unearthed from the Late Triassic of Southern Brazil. The vertebrae are proportionately longer than that of older forms and proportionately shorter than that of younger ones. Therefore, our results demonstrate that the elongation of the neck of sauropodomorphs is an example of gradual evolutionary process. Except by its elongated shape, the general anatomy of the cervical elements resembles that of the earliest forms (i.e., have a conservative anatomy). Combined with previous data, it is possible to conclude that the shape of the skull and teeth, as well as the neck proportions, were the first structures to clearly differ derived sauropodomorphs from early diverging forms. Finally, some of the recovered phylogenetic scenarios favor the origins of the elongated neck in the clade Bagualosauria., (© 2022 American Association for Anatomy.)

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., (© 2023 American Association for Anatomy.)

Several new early sauropodomorphs have been described from Carnian South American strata that include the oldest unambiguous dinosaurs worldwide. Hence, these findings suggest a high diversity in the origin of the group. Here we offer three hypotheses based in novel data that can explain this diversity at the first branches of the long evolutionary tree of the sauropodomorphs. The first hypothesis explains that the Triassic specimens excavated from Brazilian strata are not coeval owing to the lack of stratigraphic control. Fortunately, new studies are constraining the age of Triassic outcrops from Brazil. The second hypothesis suggests an overstated diversity in response to the unknown ontogenetic pathways adopted by early dinosaurs. This hypothesis still demands new findings in order to clarify these ontogenetic pathways. The third hypothesis supports a high diversity in the same time span in response to distinct ecological roles adopted by the early sauropodomorphs. Indeed, there are specimens with different tooth morphologies, indicating diverse feeding strategies. This hypothesis is supported in an ecomorphological analysis derived from discrete anatomical traits. Therefore, although facing many conflicting questions regarding alpha taxonomy of Carnian sauropodomorphs, new discoveries and alternative approaches are leading towards a better understanding of the early evolution of Sauropodomorpha. [ABSTRACT FROM AUTHOR]

The southern Goiás state region of Central Brazil has an extensive and informative record of fossil biota. Particularly over the last five years, there has been a great increase in fossil finds, which has enabled a greater understanding of this region's fauna and flora during the Late Cretaceous. In this article, we provide an updated synthesis of the biota from the Cretaceous of the southern Goiás state, the record of plants, gastropods, turtles, crocodilians, titanosaurs, and theropod dinosaurs. [ABSTRACT FROM AUTHOR]

A fossil spine, originally described as belonging to Perciformes from the Late Cretaceous Marilia Formation, Bauru Basin, Southeastern Brazil, is here restudied based on paleohistology. In addition to the overall morphology of the spine, our histological results point to the presence of pseudolamellar bone with embedded star-shaped osteocytes. These results confirm the recent redescription of this specimen as a Siluriformes, and confirm the absence, so far, of Percomorpha in freshwater deposits from the Cretaceous of Brazil and South America. [ABSTRACT FROM AUTHOR]

Abelisaurid theropods dominated the predator role across Gondwana during the Late Cretaceous. They are characterized by highly reduced forelimbs and one of the most specialized cranial morphologies among carnivorous dinosaurs, exemplified by a broad skull, short rostrum, high occipital region, and highly kinetic intramandibular joint, suggestive of a specialized feeding strategy. Late Cretaceous abelisaurids are known from some remarkably complete taxa with well-preserved skulls. However, little is known about the pattern of character transformation that led to their highly modified condition because there are no well-preserved abelisaurids before the Late Cretaceous. Here we report a basal abelisaurid from the Early Cretaceous of Brazil that preserves a complete skull and reveals an early stage in the cranial evolution of the group. It lacks the specialized temporal and mandibular features characteristic of derived abelisaurids, including the kinetic intramandibular joint and knoblike dorsal projection of the parietals. [ABSTRACT FROM AUTHOR]

Although the knowledge of bone histology of non-avian theropods has advanced considerably in recent decades, data about the bone tissue patterns, growth dynamics and ontogeny of some taxa such as abelisauroids are still limited. Here we describe the bone microstructure and growth dynamics of the Brazilian noasaurine Vespersaurus paranaensis using five femora and six tibiae and quantify the annual growth marks through retrocalculation of missing ones to estimate ontogenetic ages. The femoral series comprises four femoral histological classes (FHC I-IV), varying from two annuli or LAGs to seven LAGs. Femora show that sexual maturity was achieved around the seventh to tenth year of life, whereas the tibiae suggest it was earlier (around three to five years old). Tibiae represent three histological classes (THC I-III) displaying from three to nine LAGs. Two tibiae (THC III) exhibit an external fundamental system indicating that these specimens reached full skeletal size. The heterogeneous maturity observed in Vespersaurus hind limb bones could result from differential allometry scaling between femora and tibiae length with the body length. The predominant parallel-fibered bone matrix suggests that Vespersaurus grew more slowly than most theropods, including other abelisauroids, in a pattern shared with the noasaurines Masiakasaurus knopfleri from Madagascar and CPPLIP 1490 from Brazil. This deviation from the typical theropod growth pattern may be mainly correlated with small body size, but also may related to resource limitation imposed by the arid climate prevailing in southwestern Gondwana during Cretaceous. Moreover, given the ecological and phylogenetic similarities among these taxa, such features would probably be apomorphic within Noasauridae. [ABSTRACT FROM AUTHOR]

Several new sauropodomorphs have been described in recent years, including the unaysaurid sauropodomorph Macrocollum itaquii (Late Triassic, Brazil). This study presents a detailed description of the craniomandibular anatomy of M. itaquii based on the holotype, a paratype and a newly referred specimen. A phylogenetic analysis using an updated dataset is performed to test a previous hypothesis regarding the affinities of this taxon and its potential influence in the phylogeny of Triassic and Early Jurassic sauropodomorphs. The taxon is supported as a member of Unaysauridae. This clade is recovered as the basal-most group within Massopoda rather than the sister group to Plateosauria. However, the position of M. itaquii (and unaysaurids) is likely to be highly labile due to specific, transitional aspects of its anatomy. The most recently discovered M. itaquii specimen, in conjunction with other newly discovered specimens, serve to elucidate the transition from slender basal sauropodomorphs to more robust derived members within this group. [ABSTRACT FROM AUTHOR]

The new ichnospecies Paleohelcura araraquarensis isp. nov. is described from the Upper Jurassic-Lower Cretaceous Botucatu Formation of Brazil. This formation records a gigantic eolian sand sea (erg), formed under an arid climate in the south-central part of Gondwana. This trackway is composed of two track rows, whose internal width is less than one-quarter of the external width, with alternating to staggered series, consisting of three elliptical tracks that can vary from slightly elongated to tapered or circular. The trackways were found in yellowish/reddish sandstone in a quarry in the Araraquara municipality, São Paulo State. Comparisons with neoichnological studies and morphological inferences indicate that the producer of Paleohelcura araraquarensis isp. nov. was most likely a pterygote insect, and so could have fulfilled one of the ecological roles that different species of this group are capable of performing in dune deserts. The producer could have had a herbivorous or carnivorous diet or been part of the fauna of omnivores, being able to adopt herbivorous, carnivorous, and saprophagous diets when necessary. In modern dune deserts, some species of pterygote insects are detritivores (like Tenebrionidae), relying on organic matter that accumulated among the sand grains of the dunes during dry periods with no plant growth. The presence of additional burrows suggests that the Botucatu paleodesert would have had a detritivorous fauna like this. Based on the interpretation of the ichnofossil producers, it was possible to reconstruct the food web of this paleodesert. All the omnivorous and herbivorous invertebrates and the herbivorous ornithopod dinosaurs made up the primary consumers. These animals were, in turn, the food source for bigger carnivorous or omnivorous animals unable to feed on detritus, like arachnids, possible predatory insects, mammaliaforms, and theropod dinosaurs. The highest trophic level was occupied by larger theropod dinosaurs and mammaliaforms, which, because of their size, could prey upon a wide range of animals. The producer of Paleohelcura araraquarensis isp. nov. could have been a primary consumer if it were an omnivorous detritivore or a herbivore, or a secondary consumer if it were produced by a predatory insect or an omnivore relying on animal biomass. The description of this new trackway expands the knowledge on the faunal composition of the Botucatu paleodesert and provides insights into the ecological relationships in ancient deserts. The presence of these arthropod trackways in Mesozoic eolian deposits helps to trace a continuity between Paleozoic and post-Paleozoic desert ichnofaunas, further reinforcing a single Octopodichnus—Entradichnus Ichnofacies for eolian deposits. [ABSTRACT FROM AUTHOR]

We present a systematic revision of the 'prosauropod' dinosaur Unaysaurus tolentinoi. Past phylogenetic treatments of this taxon have presented it as a key constituent of the low-diversity Plateosauridae. This clade, along with Massospondylidae, is currently regarded as a relatively non-controversial example of monophyly within non-sauropodan sauropodomorphs – an otherwise pectinate grade of animals from which the apically nested Sauropoda is derived. The inclusion of Unaysaurus within Plateosauridae is primarily dependent on similarities shared with the Northern Hemisphere taxon Plateosaurus, with a sister-taxon relationship between these taxa indicating the earliest known instance of Pangaean cosmopolitanism among early sauropodomorphs. However, an in-depth exploration of the character states that in the past have produced this relationship shows that many either present a complex distribution throughout early Sauropodomorpha, or are subject to ambiguities in the formulation and scoring of primary homologies. An updated cladistic analysis finds weak continued support for a sister-taxon relationship between Unaysaurus and Plateosaurus; however, this result is supported by synapomorphies that are either labile with respect to taxon inclusion, not exclusively restricted to the clade, or represented by character-state dichotomies of relatively subtle differentiation. These uncertainties aside, the validity of Unaysaurus tolentinoi remains supported by several unambiguous autapomorphies. Although strong anatomical evidence for monophyletic divergences amongst early sauropodomorphs remains elusive, the relatively low stratigraphical occurrence of Unaysaurus demonstrates that the typical 'prosauropod' bauplan – and hence habitual herbivory – had evolved by the early Norian. [ABSTRACT FROM AUTHOR]

Predatory dinosaurs were an important ecological component of terrestrial Mesozoic ecosystems. Though theropod dinosaurs carried this role during the Jurassic and Cretaceous Periods (and probably the post-Carnian portion of the Triassic), it is difficult to depict the Carnian scenario, due to the scarcity of fossils. Until now, knowledge on the earliest predatory dinosaurs mostly relies on herrerasaurids recorded in Carnian strata of South America. Phylogenetic investigations recovered the clade in different positions within Dinosauria, whereas fewer studies challenged its monophyly. Although herrerasaurid fossils are much better recorded in present-day Argentina than in Brazil, Argentinean strata so far yielded no fairly complete skeleton representing a single individual. Here, we describe Gnathovorax cabreirai, a new herrerasaurid based on an exquisite specimen found as part of a multitaxic association form southern Brazil. The type specimen comprises a complete and well-preserved articulated skeleton, preserved in close association (side by side) with rhynchosaur and cynodont remains. Given its superb state of preservation and completeness, the new specimen sheds light into poorly understood aspects of the herrerasaurid anatomy, including endocranial soft tissues. The specimen also reinforces the monophyletic status of the group, and provides clues on the ecomorphology of the early carnivorous dinosaurs. Indeed, an ecomorphological analysis employing dental traits indicates that herrerasaurids occupy a particular area in the morphospace of faunivorous dinosaurs, which partially overlaps the area occupied by post-Carnian theropods. This indicates that herrerasaurid dinosaurs preceded the ecological role that later would be occupied by large to medium-sized theropods. [ABSTRACT FROM AUTHOR]

Saturnalia tupiniquim is a sauropodomorph dinosaur from the Late Triassic (Carnian–c. 233 Ma) Santa Maria Formation of Brazil. Due to its phylogenetic position and age, it is important for studies focusing on the early evolution of both dinosaurs and sauropodomorphs. The osteology of Saturnalia has been described in a series of papers, but its cranial anatomy remains mostly unknown. Here, we describe the skull bones of one of its paratypes (only in the type-series to possess such remains) based on CT Scan data. The newly described elements allowed estimating the cranial length of Saturnalia and provide additional support for the presence of a reduced skull (i.e. two thirds of the femoral length) in this taxon, as typical of later sauropodomorphs. Skull reduction in Saturnalia could be related to an increased efficiency for predatory feeding behaviour, allowing fast movements of the head in order to secure small and elusive prey, a hypothesis also supported by data from its tooth and brain morphology. A principal co-ordinates analysis of the sauropodomorph jaw feeding apparatus shows marked shifts in morphospace occupation in different stages of the first 30 million years of their evolutionary history. One of these shifts is observed between non-plateosaurian and plateosaurian sauropodomorphs, suggesting that, despite also having an omnivorous diet, the feeding behaviour of some early Carnian sauropodomorphs, such as Saturnalia, was markedly different from that of later Triassic taxa. A second shift, between Late Triassic and Early Jurassic taxa, is congruent with a floral turnover hypothesis across the Triassic-Jurassic boundary. [ABSTRACT FROM AUTHOR]

Sauropodomorphs are the most abundant and diverse clade of Triassic dinosaurs, but the taxonomy of their earliest (Carnian) representatives is still poorly understood. One such taxon is Pampadromaeus barberenai, represented by a nearly complete disarticulated skeleton recovered from the upper part of the Santa Maria Formation of Rio Grande do Sul, Brazil. Here, the osteology of Pam. barberenai is fully described for the first time. Detailed comparisons with other Carnian sauropodomorphs reveal a unique anatomy, corroborating its status as a valid species. Potential autapomorphies of Pam. barberenai can be seen in the articulation of the sacral zygapophyses, the length of the pectoral epipodium, the shape of the distal articulation of the femur and the proximal articulation of metatarsal 1. A novel phylogenetic study shows that relationships among the Carnian sauropodomorphs are poorly constrained, possibly because they belong to a “zone of variability”, where homoplasy abounds. Yet, there is some evidence that Pam. barberenai may nest within Saturnaliidae, along with Saturnalia tupiniquim and Chromogisaurus novasi, which represents the sister group to the larger sauropodomorphs, i.e. Bagualosauria. [ABSTRACT FROM AUTHOR]

The Wachholz site (Caturrita Formation, Late Triassic), in Agudo, Rio Grande do Sul (RS), southern Brazil, has yielded several sauropodomorphs. This includes CAPPA/UFSM 0002, described here based on associated elements from the basalmost portion of the site. The specimen possesses a set of traits shared with typical 'prosauropods': a concave caudal margin of the trunk neural spines and a broadly convex proximal end of metacarpal V. However, it also retains some plesiomorphic features, for instance, the slender pedal digit I. Some bones closely resemble those of Unaysaurus tolentinoi, the other definitive sauropodomorph from the Caturrita Formation, an affinity corroborated by a new phylogenetic analysis. An updated biostratigraphic framework correlates the Wachholz, Água Negra (São Martinho da Serra/RS) and Botucaraí Hill (Candelária/RS) sites based on their sample of sauropodomorphs. In addition, the record of Jachaleria in the Botucaraí Hill site, a dicynodont also known from early Norian deposits of Argentina, indicates an equivalent age to deposits bearing U. tolentioni. Accordingly, a more constrained age is proposed for the Água Negra site. This is important as the early Norian marks the transition from an epoch of low sauropodomorphs representativeness to a period of extreme abundance of the group in Early-to-Middle Mesozoic ecosystems. [ABSTRACT FROM AUTHOR]

Although Titanosauria is the most diverse and late-surviving sauropod lineage, cranial elements are known for just over 24 of its 70+ genera - the vast majority of which are fairly fragmentary and restricted to the Late Cretaceous. Only three complete titanosaur skulls have been described to date; two of these are from the latest Cretaceous ( Nemegtosaurus, Rapetosaurus), and the third, Tapuiasaurus, is from the Early Cretaceous (Aptian). In this contribution, we build on the initial treatment of the taxon by providing a complete description of the cranial elements that benefits from additional preparation and computed tomography imaging. We identify six additional features diagnosing Tapuiasaurus macedoi, including a jugal with an elongate lacrimal process forming much of the posteroventral border of the antorbital fenestra, a lateral temporal fenestra divided by a second squamosal-postorbital contact, and upper jaw teeth with labial wear facets. We directed the new morphological data in Tapuiasaurus as well as other observations towards a re-analysis of its phylogenetic position within Titanosauria. Our analysis yielded 34 most parsimonious trees, most of which recovered Tapuiasaurus in a basal position adjacent to the Early Cretaceous taxa Malawisaurus and Tangvayosaurus, but two trees recovered it within Late Cretaceous nemegtosaurids. We explored the effects of missing data and missing stratigraphic ranges on our results, concluding that (1) when missing data levels are high, resolution of even small amounts of that missing data can have dramatic effects on topology, (2) taxa that are mostly scored for characters that cannot be scored in other taxa may be topologically unstable and (3) there were several suboptimal trees that had greatly improved stratigraphic fit with relatively little compromise in terms of tree length. [ABSTRACT FROM AUTHOR]

Titanosaurian dinosaurs include some of the largest land-living animals that ever existed, and most were discovered in Cretaceous deposits of Argentina. Here we describe the first Brazilian gigantic titanosaur, Austroposeidon magnificus gen. et sp. nov., from the Late Cretaceous Presidente Prudente Formation (Bauru Group, Paraná Basin), São Paulo State, southeast Brazil. The size of this animal is estimated around 25 meters. It consists of a partial vertebral column composed by the last two cervical and the first dorsal vertebrae, all fairly complete and incomplete portions of at least one sacral and seven dorsal elements. The new species displays four autapomorphies: robust and tall centropostzygapophyseal laminae (cpol) in the last cervical vertebrae; last cervical vertebra bearing the posterior centrodiapophyseal lamina (pcdl) bifurcated; first dorsal vertebra with the anterior and posterior centrodiapophyseal laminae (acdl/pcdl) curved ventrolaterally, and the diapophysis reaching the dorsal margin of the centrum; posterior dorsal vertebra bearing forked spinoprezygapophyseal laminae (sprl). The phylogenetic analysis presented here reveals that Austroposeidon magnificus is the sister group of the Lognkosauria. CT scans reveal some new osteological internal features in the cervical vertebrae such as the intercalation of dense growth rings with camellae, reported for the first time in sauropods. The new taxon further shows that giant titanosaurs were also present in Brazil during the Late Cretaceous and provides new information about the evolution and internal osteological structures in the vertebrae of the Titanosauria clade. [ABSTRACT FROM AUTHOR]

Abelisauridae is a diverse clade of theropod dinosaurs, geographically well-distributed especially in the southern continents during the Cretaceous. The record of abelisaurids in South America comes mainly from Patagonia, whereas in Brazil they are mostly represented by numerous dental crowns and isolated bones, with few formally named species, mostly coming from the Late Cretaceous beds of the Bauru Group. In this contribution, we describe a small abelisaurid mid-caudal vertebra (LPRP/USP L0020) from the Presidente Prudente Formation, Bauru Group. LPRP/USP L0020 bears several abelisaurid features, such as an almost flat ventral surface, a poorly constrict centrum, lack of pneumatization, and distally positioned transverse processes. Body length estimation suggest that LPRP/USP L0020 belonged to a roughly 3.4 m long adult animal, representing one of the smallest known abelisaurids. The discovery of LPRP/USP L0020 indicates that Late Cretaceous abelisaurids from central South America were more diverse in body size than previously known, and possibly as diverse as their Patagonian counterparts. • Abelisauridae are the main group of theropods found in the Bauru Basin, Late Cretaceous, Brazil. • A new vertebra of Abelisauridae (LPRP/USP L0020) is described from Osvaldo Cruz, São Paulo, Presidente Prudente Formation. • LPRP/USP L0020 is regarded belonging to a small size Abelisauridae. • LPRP/USP L0020 suggests that abelisaurids were highly diverse in central South America during the Late Cretaceous. [ABSTRACT FROM AUTHOR]

In South America, little is known about Jurassic dinosaurs, contrasting with the extensive record of the late Triassic and Cretaceous, mainly in a vast area corresponding to the northern half of South America (west Gondwana). Herein, we describe for the first time a theropod dinosaur recovered from the Aliança Formation of the Jatobá Basin, represented by a caudal vertebra. Compared with theropods from the Jurassic, the specimen from Brazil is closer related to the basal neotheropods such as Dilophosaurus wetherilli , from the early Jurassic of North America. Basal neotheropods exhibited a worldwide distribution during the early Jurassic period, as suggested by the record in North America, South Africa and Antarctica. Thus, the new record from the Brazil suggests the survival of the basal lineage represented by Dilophosaurus and close relatives during the Middle-Late Jurassic. The new fossil occurrence described here also enables a worldwide correlation, reinforcing a Jurassic rather than a Late Triassic age for the Aliança Formation, for which it is provisionally assigned a Middle-Late Jurassic age. • In northern South America, little is known about Jurassic dinosaurs. • We describe a basal neotheropod dinosaur recovered from the Aliança Formation. • It constitutes the oldest record for the Jurassic in Brazil. • The fossil reinforcing a Jurassic rather than a Late Triassic age for the Aliança Formation. [ABSTRACT FROM AUTHOR]

Abstract: Dinosaur footprints found in an outcrop of the Caturrita Formation (Rio Grande do Sul State, Southern Brazil), associated with a diverse and well preserved record of fauna and flora, reopen the debate about its exclusive Triassic age. The studied footprints were identified as Eubrontes isp. and are interpreted as having been produced by large theropod dinosaurs. The morphological characteristics and dimensions of the footprints are more derived than those commonly found in the Carnian–Norian, and are more consistent with those found during the Rhaetian–Jurassic. The trackmaker does not correspond to any type of dinosaur yet known from Triassic rocks of Brazil. Recent studies with the paleofloristic content of this unit also support a more advanced Rhaetian or even Jurassic age for this unit. [Copyright &y& Elsevier]

Abstract: In this study, we describe a small theropod dorsal vertebra from the Late Cretaceous Bauru Group (Brazil). The specimen is referred to the maniraptoran clade Unenlagiidae based on the following combination of characters: diapophyses short, wide and weakly inclined; dorsal surface of the neural spine transversely expanded; neural spine at least twice as high than it is long at mid-height; and deep lateral excavations of the ventrolateral surface of the neural spine. The vertebra belonged to an ontogenetically mature individual with an estimate total body length of around 1 m. This is the first evidence of Unenlagiidae in Brazil, a clade currently known only from Argentina and possibly Madagascar. The presence of large- to small-bodied forms in the Turonian–Santonian of South America indicates that Unenlagiinae were ecologically disparate during the first half of the Cretaceous. The Bauru vertebra shows a combination of avian-like, Rahonavis-like and Unenlagia-like features, making it a possible pivotal taxon in future phylogenetic investigations of intra- and interrelationships of unenlagiids. [Copyright &y& Elsevier]

Abstract: An isolated caudal vertebral centrum of a theropod dinosaur was discovered in the Bauru Basin (Late Cretaceous) of Brazil, in the Maastrichtian São José do Rio Preto Formation. The vertebral centrum has pneumatic features that are similar to those in the megaraptoran theropods Aerosteon, Megaraptor, and Orkoraptor. For example, all these taxa share with the caudal centrum here described the presence of true pleurocoels or pneumatic foramina, immersed within a depression or fossa. Thus, the specimen is considered the first record of Megaraptora in Brazil. The present analysis provides new information on the vertebral caudal anatomy of this clade of bizarre Cretaceous theropods. [Copyright &y& Elsevier]

The ichthyofauna of the Lower Cretaceous Quiricó Formation (Sanfranciscana Basin), Minas Gerais, Brazil, comprises so far taxa like Hybodontiformes (Chondrichthyes), Dastilbe , Laeliichthys , Mawsonia , and isolated Amiidae teeth and Semionotiformes scales. Here we report new remains of a dipnoan tooth plate and its associated pterygopalatine and Lepisosteidae material comprising isolated scales, a hyoid arch, and a partially preserved individual including several scales, vertebrae, neural and haemal spines, pterygiophores, and associated anal fin. Although isolated or incomplete, these new fossils, collected from upper sandstone levels of fluvio-lacustrine deposits, increase the diversity of the ichthyofauna of the Quiricó Formation. This discovery adds important information to the understanding of the relationships of Brazilian and African faunas during the initial stages of the opening of the Atlantic Ocean. • New Lepisosteidae and dipnoan fossils from the Cretaceous Quiricó Formation, Brazil. • Increase of Lower Cretaceous Lepisosteidae sites in South America. • Quiricó Formation fauna is similar to coeval North African ones. [ABSTRACT FROM AUTHOR]

This work aimed to investigate the ichnofossiliferous sites in Nioaque and surrounding region, Mato Grosso do Sul state, Brazil, analyzing their paleontological, stratigraphic and paleoenvironmental context, because dinosaur tracks were found in an area previously mapped as Permo–Carboniferous age. Some sedimentary facies previously assigned to the glacial Aquidauana Formation were herein reinterpreted as part of the basal section of the Botucatu Formation (Late Jurassic/Early Cretaceous) and include floodplain and residual channel deposits, possibly representing the lower half of this formation's sequence in the studied area. The ichnofossils that have been found include both isolated tracks of Theropoda and Ornithopoda, a trackway of Eubrontes isp., a vertebrate burrow and invertebrate traces (Palaeophycus) possibly related to the Entradichnus ichnofacies. Sedimentological interpretation suggests the existence of a river system just before the deposition of the typical Botucatu eolian facies in this region. This is the first documented record of fluvial deposits transitionally to the traditional eolian Botucatu Formation. Noteworthy, the dinosaur tracks have played a key role for the interpretation of these rocks as Botucatu Formation and for better understanding the whole system due to the impossible Paleozoic age (dinosaur tracks). • First occurrence of fluvial deposits related to the desertic Botucatu Formation. • Dinosaur tracks, vertebrate burrows and invertebrate ichnofossils were documented. • A significant part of Permian Aquidauana Formation is reinterpreted as Jurassic—Cretaceous Botucatu Formation. • Sedimentological interpretation suggesting a fluvial system at the basal section of the Botucatu Formation. [ABSTRACT FROM AUTHOR]

The early evolution of theropod dinosaurs is poorly understood. Whereas sauropodomorphs are well-known from the oldest dinosaur bearing outcrops, the record of theropods is fragmentary and ambiguous. The Triassic deposits from Brazil yielded some of the oldest dinosaurs worldwide. These dinosaurs came from two distinct Assemblage Zones (AZ): the Hyperodapedon AZ (Carnian) and the Riograndia AZ (early Norian). Here, a specimen previously assigned to cf. Dinosauromorpha is reassessed. CAPPA/UFSM 0157 comes from an enigmatic assemblage with predominance of the traversodotind cynodont Siriusgnathus. This assemblage has been tentatively assigned to the Riograndia AZ. However, the absence of index fossils still hampers a reliable assignation. The specimen, which comprises a proximal portion of a left femur, belongs to a new theropod taxon erected here as Erythrovenator jacuiensis gen. et sp. nov. The new dinosaur differs from all other known Triassic dinosaurs based on the absence of a raised dorsolateral trochanter of the femur. Erythrovenator jacuiensis gen. et sp. nov. is regarded as a theropod on the basis of the pyramidal shape of the anterior trochanter in anterior view. The results of a phylogenetic analysis corroborate this assignation. Therefore, the new dinosaur represents one of the oldest theropod dinosaurs worldwide, shedding lights on some of the earliest theropod features. Finally, the new specimen also represents the first carnivorous dinosaur from the assemblage dominated by the traversodontid cynodont Siriusgnathus , increasing our knowledge of the faunal content of this enigmatic assemblage. • A new theropod dinosaur from the Late Triassic of Brazil is described. • It is one of the oldest known theropods worldwide. • This sheds light on some of the earliest theropod features. • The new theropod comes from a peculiar fauna dominated by traversodontid cynodonts. • The new theropod represents the first carnivorous dinosaur from this assemblage. [ABSTRACT FROM AUTHOR]

Theropod tooth crowns are abundant in the Upper Cretaceous (post-Coniacian) continental deposits of the Bauru Group, Brazil. The distribution of anatomical crown features indicates that a variety of carnivorous dinosaurs inhabited the area at that time, which is consistent with fossil records from other parts of Gondwana. More specifically, some authors have attributed several isolated specimens to the Carcharodontosauridae; while this has important implications for palaeobiogeography and paleoecology, other scholars have argued that the clade became extinct during the Turonian. In this study, we conducted discriminant and phylogenetic analyses for 18 crowns putatively assigned to the Carcharodontosauridae. In short, the discriminant analysis suggested that the specimens should be tentatively assigned to the following groups: non-abelisauroid Ceratosauria, Abelisauridae, Neovenatoridae, Dromaeosauridae, and Pantyrannosauria. By contrast, the phylogenetic analysis indicated that all should be assigned to abelisaurid theropods, which is consistent with the theropod osteological records in both Brazil and Argentina. We recommend using a combined approach involving morphometric and phylogenetic tools when identifying isolated teeth, as this may yield more reliable identifications. We also suggest that all previous reports on the presence of post-Turonian carcharodontosaurids in the Bauru Group are invalid, which also corroborates previous work. Our results indicate that abelisaurids from the Bauru Basin were diverse in morphology and activity; that is, many were quite large and/or played important ecological roles. Findings also support the hypothesis that this taxon had a preference for semi-arid environments. • Several Carcharodontosauridae isolated crowns from Upper Cretaceous of Brazil were reassessed. • Morphological, phylogenetic and morphometric tests were performed. • The materials belong to indeterminate Abelisauridae. • Abelisauridae from Bauru Basin were well diverse and reached large body-sizes. [ABSTRACT FROM AUTHOR]

The titanosaurs were diverse at the end of the Cretaceous of Brazil. Here we describe several new titanosaur remains of outcrops in the Cachoeira do Bom Jardim Formation, Cambambe Basin, (Upper Cretaceous), collected near the Jangada Roncador community, Chapada dos Guimarães municipality, Mato Grosso, Brazil. Although fragmentary, these specimens indicate the presence of two different sizes bone groups, suggesting, possible, at least two individuals. Despite not having enough diagnostic elements to identify a new species, they are different from the Brazilian species previously described. The area of study in this work has an importance, since with materials collected in this locality was described the species Pycnonemosaurus nevesi. Finally, the titanosaur's fauna of Jangada Roncador can be related to other occurrences, such as the Late Cretaceous Bauru Group, indicating a higher diversity of Brazilian titanosaurians than previously thought. • New importante titanosaur sauropods from the Late Cretaceous Ribeirao Boiadeiro Formation. • Titanosaur dinosaur diversity of the Central Brazil. • Upper Cretaceous Ribeirao Boiadeiro Formation has contributed to South American titanosaurian knowledgment. [ABSTRACT FROM AUTHOR]

Araripe Basin has a large wealth fossil localities represented by diversity and abundance of animals and plants with excellent preservation state. Among these animals, the fishes that are represented by 30 known species stand out, including the Coelacanthiforme. This group of fishes is one of the rarest in the fossil record and three species were identified to the Jurassic and Cretaceous of Araripe Basin so far: Mawsonia gigas Woodward 1907 in Brejo Santo and Romualdo formations; Mawsonia brasiliensis Yabumoto 2002 in the Romualdo Formation and; Axelrodichthys araripensis Maisey 1986 in the Crato and Romualdo formations. This paper encompasses the Mawsoniidae studies, including all the species, distributed in Brejo Santo (Tithonian), Crato (Aptian) and Romualdo (Albian) formations, with a new record of Mawsoniidae to Barbalha (Aptian) Formation. • New record of Mawsoniidae to Barbalha Formation. • Expansion of temporal distribution of Mawsoniidae in Mesozoic. • The third specimen of Mawsonia brasiliensis described in literature. [ABSTRACT FROM AUTHOR]

Two new ascaridoid species, Bauruascaris cretacicus n. gen. et n. sp., and Bauruascaris adamantinensis n. gen. et n. sp., are described based on the fossils of eggs preserved in 80–70 million year old phosphatized coprolites of Crocodyliformes, chronologically assigned to the Upper Cretaceous (Campanian/Maastrichtian age), collected from sedimentary rocks of the Bauru Group, Adamantina Formation in the municipality of Santo Anastácio, in the southwestern region of the state of São Paulo, Brazil, South America. This paper describes the oldest ascaridoid species ever recorded in Crocodylomorpha. Hence, this article contributes to the body of knowledge about the evolutionary history of this nematode group. It also offers a clue about the composition of the parasite fauna of these reptiles from the Late Cretaceous, which is still unknown despite numerous studies about various aspects of their biology and the pioneering paleoparasitological analysis of animal coprolites by South American researchers. Unlabelled Image • Two new ascaridoids are described based on fossils of eggs in 80–70 mya Crocodylomorpha coprolites. • This paper reports the oldest Ascaridoidea species parasitic in Crocodyliformes. • Bauruascaris is the second oldest genus Ascaridoidea recorded in the literature. [ABSTRACT FROM AUTHOR]

A new paraclupeid fish, Tunisiaclupea speratus, gen. et sp. nov., is described from the Upper Barremian (Early Cretaceous) of the Chotts Basin, southern Tunisia. With a series of predorsal scutes of different size and shape, it is distinguished from other paraclupeids by the following combination of characters: anterior neural spines unfused; first uroneural bearing a dorsal laminar expansion and extending anteriorly nearly to third preural centrum; and hypural diastema present. The results of a phylogenetic analysis reconfirmed the monophyly of Ellimmichthyiformes and resolved Sorbinichthyoidei (Gasteroclupeidae + Sorbinichthyidae) as the most basal clade, with the Diplomystus clade the next, Armigatidae more derived than Diplomystus clade but with few diagnostic features, and Paraclupeidae with well-supported monophyly. Tunisiaclupea was resolved as a basal paraclupeid and an intermediate lineage between Ellimma branneri from the Lower Cretaceous of Brazil and Tycheroichthys dunveganensis from the Upper Cretaceous of North America. Tunisiaclupea is among the oldest ellimmichthyiforms known so far and extends the distribution of Paraclupeidae to the southern Mediterranean Tethys in the Early Cretaceous. Ellimmichthyiform diversity reached its peak in the Mediterranean region during the early Late Cretaceous, which might have resulted from allopatric speciation promoted by the sea-level highstand and the consequential land-sea distribution with increased food input, dispersal routes, and habitat fragmentation for these fishes. [ABSTRACT FROM AUTHOR]

The Late Triassic (Carnian) upper Santa Maria Formation of south Brazil has yielded some of the oldest unequivocal records of dinosaurs. Here, we describe a new saurischian dinosaur from this formation, Nhandumirim waldsangae, gen. et sp. nov., based on a semiarticulated skeleton, including trunk, sacral, and caudal vertebrae, one chevron, right ilium, femur, partial tibia, fibula, and metatarsals II and IV, as well as ungual and non-ungual phalanges. The new taxon differs from all other Carnian dinosauromorphs through a unique combination of characters, some of which are autapomorphic: caudal centra with sharp longitudinal ventral keels; brevis fossa extending for less than three-quarters of the ventral surface of the postacetabular ala of the ilium; dorsolateral trochanter ending well distal to the level of the femoral head; distal part of the tibia with a mediolaterally extending tuberosity on its cranial surface and a tabular caudolateral flange; conspicuous, craniomedially oriented semicircular articular facet on the distal fibula; and a straight metatarsal IV. This clearly distinguishes Nhandumirim waldsangae from both Saturnalia tupiniquim and Staurikosaurus pricei, which were collected nearby and at a similar stratigraphic level. Despite not being fully grown, the differences between Nhandumirim waldsangae and those saurischians cannot be attributed to ontogeny. The phylogenetic position of Nhandumirim waldsangae suggests that it represents one of the earliest members of Theropoda. Nhandumirim waldsangae shows that some typical theropod characters were already present early in dinosaur evolution, and it represents possibly the oldest record of the group known in Brazil. [ABSTRACT FROM AUTHOR]

The rise of sauropodomorphs is still poorly understood due to the scarcity of well-preserved fossils in early Norian rocks. Here, we present an association of complete and exceptionally well-preserved dinosaur skeletons that helps fill that gap. They represent a new species, which is recovered as a member of a clade solely composed of Gondwanan Triassic taxa. The new species allows the definition of a set of anatomical changes that shaped sauropodomorph evolution along a period from 233 to 225 Ma, as recorded in the well dated Late Triassic beds of Brazil. In that time span, apart from achieving a more herbivorous diet, sauropodomorph dinosaurs increased their size in a ratio of 230% and their typical long neck was also established, becoming proportionally twice longer than those of basal taxa. Indeed, the new dinosaur is the oldest-known sauropodomorph with such an elongated neck, suggesting that the ability to feed on high vegetation was a key trait achieved along the early Norian. Finally, the clustered preservation mode of the skeletons represents the oldest evidence of gregarious behaviour among sauropodomorphs., (© 2018 The Author(s).)