The Early Evolution of Rhynchosaurs

The rhynchosaurian archosauromorphs are an important and diverse group of fossil tetrapods that first appeared during the Early Triassic and probably became extinct during the early Late Triassic (early Norian). Here, the early evolution of rhynchosaurs during the Early and early Middle Triassic (Induan-Anisian: 252.2-242 Mya) is reviewed based on new anatomical observations and their implications for the taxonomy, phylogenetic relationships and macroevolutionary history of the group. A quantitative phylogenetic analysis recovered a paraphyletic genus Rhynchosaurus, with “Rhynchosaurus” brodiei more closely related to hyperodapedontines than to Rhynchosaurus articeps. Therefore, a new genus is erected, resulting in the new combination Langeronyx brodiei. A body size analysis found two independent increases in size in the evolutionary history of rhynchosaurs, one among stenaulorhynchines and the other in the hyperodapedontine lineage. Maximum likelihood fitting of phenotypic evolution models to body size data found ambiguous results, with body size evolution potentially interpreted as fitting either a non-directional Brownian motion model or a stasis model. A Dispersal-ExtinctionCladogenesis analysis reconstructed the areas that are now South Africa and Europe as the ancestral areas of Rhynchosauria and Rhynchosauridae, respectively. The reconstruction of dispersal events between geographic areas that are broadly separated paleolatitudinally implies that barriers to the dispersal of rhynchosaurs from either side of the paleo-Equator during the Middle Triassic were either absent or permeable.Fil: Ezcurra, Martin Daniel. University of Birmingham; Reino Unido. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Montefeltro, Felipe C.. University of Birmingham; Reino Unido. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Butler, Richard J.. University of Birmingham; Reino Unid

The stem-archosaur evolutionary radiation in South America

The oldest archosauromorphs (dinosaurs, birds, crocodiles, and their stem-taxa) arerecorded in middle−upper Permian rocks, but it was not after the Permo−Triassic massextinction that the group shows a substantially high taxonomic richness andecomorphological disparity. The early evolutionary history of the Archosauromorphaduring the Early and Middle Triassic is mainly based on fossils recovered from rocks insouthern Africa, Europe and Asia, whereas South America possesses a morecomplete fossil record of the group only in the Late Triassic. Here we revisit, discuss,and reanalyse the non-archosaurian archosauromorph fossil record of the current-daySouth America. The Early Triassic archosauromorph record in this continent is stillscarce, but it documents the early evolution of the group in western Pangaea and iscrucial to understand more globally the biotic recovery after the Permo−Triassic massextinction. The Middle Triassic record is extremely scarce, but the Late Triassicarchosauromorph assemblage of South America is among the most diverse andabundant worldwide. The last decade has witnessed a considerable improvement inour knowledge of the record, taxonomy, phylogeny, and macroevolution of the groupwith the input from the South American fossils. Nevertheless, a considerable amount ofresearch is needed and ideally should be focused on some particular aspects of theTriassic evolutionary radiation of Archosauromorpha. Among them, the Early Triassicrecord should be expanded, more numerous and more complete Middle Triassicarchosauromorph specimens are crucial to have a more complete picture of theevolution of the group, and the taxonomy of groups like proterochampsids andhyperodapedontine rhynchosaurs should be clarified through detailed anatomical work.Fil: Ezcurra, Martin Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’; ArgentinaFil: Montefeltro, Felipe C.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Pinheiro, Felipe L.. Universidade Federal do Pampa; BrasilFil: Trotteyn, Maria Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Gentil, Adriel Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’; ArgentinaFil: Lehmann, Oscar Emilio Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’; ArgentinaFil: Pradelli, Luciano Agustín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’; Argentin

The Late Triassic Ischigualasto Formation at Cerro Las Lajas (La Rioja, Argentina): fossil tetrapods, high-resolution chronostratigraphy, and faunal correlations

Present knowledge of Late Triassic tetrapod evolution, including the rise of dinosaurs, relies heavily on the fossil-rich continental deposits of South America, their precise depositional histories and correlations. We report on an extended succession of the Ischigualasto Formation exposed in the Hoyada del Cerro Las Lajas (La Rioja, Argentina), where more than 100 tetrapod fossils were newly collected, augmented by historical finds such as the ornithosuchid Venaticosuchus rusconii and the putative ornithischian Pisanosaurus mertii. Detailed lithostratigraphy combined with high-precision U–Pb geochronology from three intercalated tuffs are used to construct a robust Bayesian age model for the formation, constraining its deposition between 230.2 ± 1.9 Ma and 221.4 ± 1.2 Ma, and its fossil-bearing interval to 229.20 + 0.11/− 0.15–226.85 + 1.45/− 2.01 Ma. The latter is divided into a lower Hyperodapedon and an upper Teyumbaita biozones, based on the ranges of the eponymous rhynchosaurs, allowing biostratigraphic correlations to elsewhere in the Ischigualasto-Villa Unión Basin, as well as to the Paraná Basin in Brazil. The temporally calibrated Ischigualasto biostratigraphy suggests the persistence of rhynchosaur-dominated faunas into the earliest Norian. Our ca. 229 Ma age assignment to Pi. mertii partially fills the ghost lineage between younger ornithischian records and the oldest known saurischians at ca. 233 Ma.Fil: Desojo, Julia Brenda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Fiorelli, Lucas Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Secretaría de Industria y Minería. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja; ArgentinaFil: Ezcurra, Martin Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Martinelli, Agustín Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Ramezani, Jahandar. Massachusetts Institute of Technology; Estados UnidosFil: Da Rosa, Átila. A. S.. Universidade Federal de Santa Maria; BrasilFil: von Baczko, Maria Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Trotteyn, Maria Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Montefeltro, Felipe C.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Ezpeleta, Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Langer, Max C.. Universidade de Sao Paulo; Brasi

The Bauru Basin in São Paulo and its tetrapods

Funding Information: The authors thank the editors of Derbyana, especially its Editor-in-Chief Silvio T. Hiruma, for the invitation to participate in this volume dedicated to “Advances in Paleontology”. This contribution results from FAPESP grant 2020/07997-4, to which most of the authors are affiliated. We also thank the Derbyana ad-hoc reviewers, Drs. Agustin Martinelli and Fabiano Iori, for their helpful comments to the manuscript. FIGURE 6 – Cumulative chronological distribution of the tetrapod fossil record in the Bauru Basin of São Paulo (1913-2022) compared to science and technology funding metrics and events: A – For all tetrapods; grey bars indicate total records of tables 1-5; green line indicates taxonomic richness (grey lines in Tables 1-5); pink line indicates FAPESP budget in billions of reais between 1976 and 2021 (FAPESP 2022); blue line indicates CNPq, CAPES, and FINEP budget in millions of reais between 1996 and 2018 (ESCOBAR 2019). Events indicated by arrows correspond, in chronological sequence, to the foundations of USP, “Instituto Geográfico e Geológico”, FAPESP, Unicamp, UNESP, “Instituto Geológico”, and Monte Alto Museum of Paleontology, the implementations of the Qualis list, the Lattes curriculum, the CAPES Portal de Periódicos, and the CNPq “grant”, the foundation of the Marília Museum of Paleontology, the release of the first MCT/CNPq public call for “Strengthening National Paleontology”, and the foundation of “Pedro Candolo” Museum of Paleontology. B – Separately for each recorded tetrapod group, coloured lines indicate total of records in tables 1-5 of Anura = light blue, Crocodyliformes = red, Mammalia = purple, Sauropoda = green, Squamata = yellow, Testudines = orange, and Theropoda = dark blue. Publisher Copyright: Copyright © 2022 The Institute of Electronics, Information and Communication Engineers.The Bauru Basin bears one of the best sampled tetrapod paleofaunas of Brazil, with about 70% of this diversity collected from its deposits in São Paulo. Its fossils are known since the beginning of the 20th century, coming from all stratigraphic units of the Basin cropping-out in the state, i.e., Santo Anastácio, Araçatuba, Adamantina (alternatively divided into Vale do Rio do Peixe, Presidente Prudente, and São José do Rio Preto formations), and Marília formations. Identified taxa include rare anurans, mammals, and squamates, an important set of testudines, theropods (including birds), and sauropods, in addition to one of the most diverse crocodyliform faunas known worldwide. This congregates more than fifty unique taxonomic entities, including 42 formally described species. Based on biostratigraphic correlations (including tetrapods), on few absolute ages, and other sources of evidence, the Bauru Basin deposits in São Paulo seem to be chronologically restricted to the Late Cretaceous, but further investigation is much needed. Finally, the history of research with such fossils highlights the importance of public funding for research and decentralization of university education for the advancement of science.publishersversionpublishe

A New Baurusuchid (Crocodyliformes, Mesoeucrocodylia) from the Late Cretaceous of Brazil and the Phylogeny of Baurusuchidae

Background: Baurusuchidae is a group of extinct Crocodyliformes with peculiar, dog-faced skulls, hypertrophied canines, and terrestrial, cursorial limb morphologies. Their importance for crocodyliform evolution and biogeography is widely recognized, and many new taxa have been recently described. In most phylogenetic analyses of Mesoeucrocodylia, the entire clade is represented only by Baurusuchus pachecoi, and no work has attempted to study the internal relationships of the group or diagnose the clade and its members. Methodology/Principal Findings: Based on a nearly complete skull and a referred partial skull and lower jaw, we describe a new baurusuchid from the Vale do Rio do Peixe Formation (Bauru Group), Late Cretaceous of Brazil. The taxon is diagnosed by a suite of characters that include: four maxillary teeth, supratemporal fenestra with equally developed medial and anterior rims, four laterally visible quadrate fenestrae, lateral Eustachian foramina larger than medial Eustachian foramen, deep depression on the dorsal surface of pterygoid wing. The new taxon was compared to all other baurusuchids and their internal relationships were examined based on the maximum parsimony analysis of a discrete morphological data matrix. Conclusion: The monophyly of Baurusuchidae is supported by a large number of unique characters implying an equally large morphological gap between the clade and its immediate outgroups. A complex phylogeny of baurusuchids was recovered. The internal branch pattern suggests two main lineages, one with a relatively broad geographical range between Argentina and Brazil (Pissarrachampsinae), which includes the new taxon, and an endemic clade of the Bauru Group in Brazil (Baurusuchinae).FAPESP[2008/57642-6]Programa de Pos-Graduacao em Biologia ComparadaFFCLRP-USPPrograma Doutorando com Estagio no ExteriorCAPES[1275/10-0]CNPQCRCNSER

The Quaternary vertebrate fauna of the limestone cave Gruta do Ioio, northeastern Brazil

The present study reports the Quaternary vertebrate fauna of Gruta do Ioio, a partially submerged limestone cave located in central Bahia, northeastern Brazil. A semi-arid weather prevails nowadays in the area, which is mostly covered by a xeric low arboreal scrubland known as Caatinga. The identified taxa include: Rhamdia (Osteichtyes, Siluriformes), Caiman (Crocodyliformes, Caimaninae), Myocastor cf. Myocastor coypus (Rodentia, Myocastoridae), Holochilus sciureus (Rodentia, Sigmodontinae), Natalus cf. Natalus macrourus (Chiroptera, Natalidae), Tonatia bidens, Trachops cirrhosus (Chiroptera, Phyllostomidae), and Eira cf. Eira barbara (Carnivora, Mustelidae). Whereas Rhamdia and Caiman have scarce fossil records, the recovered mammals have already been reported from Quaternary localities of northeastern Brazil, although only two of them are present in the current local fauna. Taphonomic signatures and the nature of the fossiliferous site indicate that the vertebrates lived inside or nearby the cave, including the swamp by its main entrance. Radiocarbon dating of dental bioapatite yielded calibrated ages between 19,980 and 22,040 BP. This indicates that the accumulation started at least during the late Pleistocene, within the Last Glacial Maximum. In agreement with the mode of life of most taxa recognized here, previous studies indicated that this was a wetter period in the region. (C) 2014 Elsevier Ltd and INQUA. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Palaeoenvironmental characterization of a crocodilian nesting site from the Late Cretaceous of Brazil and the evolution of crocodyliform nesting strategies

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULODespite the vast crocodyliform fossil record, little is known about the reproductive biology and nesting strategies of the extinct members of the group. Here we report a large accumulation of crocodilian fossil eggs from the type locality of the baurusuchid Pissarrachampsa sera. Sedimentary fades and architectural elements of the site support a palaeoenvironmental model with a shallow lacustrine, playa-lake system interacting to ephemeral braided fluvial channels, with aeolian influence and development of sandy soils. The presence of pedogenic calcretes in the palaeosols indicates arid to semi-arid conditions. The crocodilian affinity of the eggs is supported by the thin eggshell which bears wedge-shaped shell units with tabular microstructures. Furthermore, taphonomic data support an autochthonous assemblage of eggs and skeletal remains, hinting at a monotypical stratigraphic horizon and suggesting P. sera as the egg-laying taxon. The repeated pattern of four (eventually five) eggs per clutch at the site demonstrates that P. sera laid fewer eggs compared to modern crocodilians, indicating that k-selected reproductive strategy pattern is pervasive in the fossil record of Notosuchia. In the crocodyliform phylogenetic framework, the k-strategy and the "egg clutch sizes" optimization of Notosuchia is opposite to the strategy with larger clutches consistently occurring in modern Crocodylia and Neosuchia, the sister Glade to Notosuchia. Yet, the lack of data on more early-branching taxa renders unclear which pattern is plesiomorphic for Crocodyliformes as a whole. (C) 2016 Elsevier B.V. All rights reserved.Despite the vast crocodyliform fossil record, little is known about the reproductive biology and nesting strategies of the extinct members of the group. Here we report a large accumulation of crocodilian fossil eggs from the type locality of the baurusuchid Pissarrachampsa sera. Sedimentary fades and architectural elements of the site support a palaeoenvironmental model with a shallow lacustrine, playa-lake system interacting to ephemeral braided fluvial channels, with aeolian influence and development of sandy soils. The presence of pedogenic calcretes in the palaeosols indicates arid to semi-arid conditions. The crocodilian affinity of the eggs is supported by the thin eggshell which bears wedge-shaped shell units with tabular microstructures. Furthermore, taphonomic data support an autochthonous assemblage of eggs and skeletal remains, hinting at a monotypical stratigraphic horizon and suggesting P. sera as the egg-laying taxon. The repeated pattern of four (eventually five) eggs per clutch at the site demonstrates that P. sera laid fewer eggs compared to modern crocodilians, indicating that k-selected reproductive strategy pattern is pervasive in the fossil record of Notosuchia. In the crocodyliform phylogenetic framework, the k-strategy and the "egg clutch sizes" optimization of Notosuchia is opposite to the strategy with larger clutches consistently occurring in modern Crocodylia and Neosuchia, the sister Glade to Notosuchia. Yet, the lack of data on more early-branching taxa renders unclear which pattern is plesiomorphic for Crocodyliformes as a whole4571221232FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO2010/14797-0; 2013/23114-1; 2010/19787-2; 2013/11358-3; 2014/03825-

An Additional Baurusuchid from the Cretaceous of Brazil with Evidence of Interspecific Predation among Crocodyliformes

<div><p>A new Baurusuchidae (Crocodyliformes, Mesoeucrocodylia), <i>Aplestosuchus sordidus</i>, is described based on a nearly complete skeleton collected in deposits of the Adamantina Formation (Bauru Group, Late Cretaceous) of Brazil. The nesting of the new taxon within Baurusuchidae can be ensured based on several exclusive skull features of this clade, such as the quadrate depression, medial approximation of the prefrontals, rostral extension of palatines (not reaching the level of the rostral margin of suborbital fenestrae), cylindrical dorsal portion of palatine bar, ridge on the ectopterygoid-jugal articulation, and supraoccipital with restricted thin transversal exposure in the caudalmost part of the skull roof. A newly proposed phylogeny of Baurusuchidae encompasses <i>A. sordidus</i> and recently described forms, suggesting its sixter-taxon relationship to <i>Baurusuchus albertoi</i>, within Baurusuchinae. Additionally, the remains of a sphagesaurid crocodyliform were preserved in the abdominal cavity of the new baurusuchid. Direct fossil evidence of behavioral interaction among fossil crocodyliforms is rare and mostly restricted to bite marks resulting from predation, as well as possible conspecific male-to-male aggression. This is the first time that a direct and unmistaken evidence of predation between different taxa of this group is recorded as fossils. This discovery confirms that baurusuchids were top predators of their time, with sphagesaurids occupying a lower trophic position, possibly with a more generalist diet.</p></div

Finite elements analysis suggests a defensive role for osteoderms in titanosaur dinosaurs (Sauropoda)

Here we present, for the first time, the use of finite element analysis to evaluate bites of two possible predators, a baurusuchid crocodyliform and an abelisaurid theropod into titanosaur osteoderms, in order to test if these structures could act as defensive tools. Our results showed that bites caused much less stress on osteoderms that did not went through internal resorption and were composed mainly by solid bone. Our data strengths the hypothesis that titanosaur osteoderms could have provided more functions than just mineral storage.Fil: Silva Junior, Julian C.G.. Universidade de Sao Paulo; BrasilFil: Montefeltro, Felipe C.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Marinho, Thiago S.. Universidade Federal Do Triangulo Mineiro; BrasilFil: Martinelli, Agustín Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Langer, Max C.. Universidade de Sao Paulo; Brasi

The largest teeth of <i>Aplestosuchus sordidus</i>.

<p>A, Third maxillary (right) tooth; B, Fourth dentary (right) tooth. Scale bar equals 2 cm.</p