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

The multi-peak adaptive landscape of crocodylomorph body size evolution

Background: Little is known about the long-term patterns of body size evolution in Crocodylomorpha, the > 200-million-year-old group that includes living crocodylians and their extinct relatives. Extant crocodylians are mostly large-bodied (3–7 m) predators. However, extinct crocodylomorphs exhibit a wider range of phenotypes, and many of the earliest taxa were much smaller ( Results: Crocodylomorphs reached an early peak in body size disparity during the Late Jurassic, and underwent an essentially continual decline since then. A multi-peak Ornstein-Uhlenbeck model outperforms all other evolutionary models fitted to our data (including both uniform and non-uniform), indicating that the macroevolutionary dynamics of crocodylomorph body size are better described within the concept of an adaptive landscape, with most body size variation emerging after shifts to new macroevolutionary regimes (analogous to adaptive zones). We did not find support for a consistent evolutionary trend towards larger sizes among lineages (i.e., Cope’s rule), or strong correlations of body size with climate. Instead, the intermediate to large body sizes of some crocodylomorphs are better explained by group-specific adaptations. In particular, the evolution of a more aquatic lifestyle (especially marine) correlates with increases in average body size, though not without exceptions. Conclusions: Shifts between macroevolutionary regimes provide a better explanation of crocodylomorph body size evolution on large phylogenetic and temporal scales, suggesting a central role for lineage-specific adaptations rather than climatic forcing. Shifts leading to larger body sizes occurred in most aquatic and semi-aquatic groups. This, combined with extinctions of groups occupying smaller body size regimes (particularly during the Late Cretaceous and Cenozoic), gave rise to the upward-shifted body size distribution of extant crocodylomorphs compared to their smaller-bodied terrestrial ancestors.</p

RNAi-mediated serotonin transporter suppression rapidly increases serotonergic neurotransmission and hippocampal neurogenesis

Open Access: This work is licensed under the Creative Commons Attribution-NonCommercial-No Derivative Works 3.0 Unported License.-- et al.Current antidepressants, which inhibit the serotonin transporter (SERT), display limited efficacy and slow onset of action. Here, we show that partial reduction of SERT expression by small interference RNA (SERT-siRNA) decreased immobility in the tail suspension test, displaying an antidepressant potential. Moreover, short-term SERT-siRNA treatment modified mouse brain variables considered to be key markers of antidepressant action: reduced expression and function of 5-HT(1A)-autoreceptors, elevated extracellular serotonin in forebrain and increased neurogenesis and expression of plasticity-related genes (BDNF, VEGF, Arc) in hippocampus. Remarkably, these effects occurred much earlier and were of greater magnitude than those evoked by long-term fluoxetine treatment. These findings highlight the critical role of SERT in serotonergic function and show that the reduction of SERT expression regulates serotonergic neurotransmission more potently than pharmacological blockade of SERT. The use of siRNA-targeting genes in serotonin neurons (SERT, 5-HT(1A)-autoreceptor) may be a novel therapeutic strategy to develop fast-acting antidepressants.This research was supported by grants from Spanish Ministry of Science and Innovation-CDTI, with the participation of the DENDRIA Consortium; from Instituto de Salud Carlos III PI10/00290 and Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM, P91C). Structural funds of the European Union, through the National Applied Research Projects (R+D+I 2008/11) and from the Catalan Government (grant 2009SGR220) are also acknowledged.Peer Reviewe

Animalia

PAN-PODOCNEMIDIDAE Joyce, Praham & Gauthier 2004 Gen. et sp. indet. Comparative description. LPRP-USP 0052 (figure 2 A) is elliptic (0,5 width/length ratio) with a missing pole. Its main axis is 5,1 cm long, whereas the minor axis range from 2,9 to 2,2 cm due to compression. Although taphonomicaly distorted, the elongation of LPRP-USP 0052 still matches that of chelids such as Elseya sp., Chelodina sp. and Hydromedusa maximilliani (Winkler 2006). This differs from the rounded shape of almost all described turtle fossil eggs (Azevedo et al. 2000; Jackson et al. 2008, table 1; Knell et al. 2011), except for those from the Jurassic of England (Hirsch 1996; Bray & Hirsch 1998), United States (Bray & Hirsch 1998) and China (Wang et al. 2013). The outer surface of the egg shows folded areas that suggest that the eggshell was flexible before its fossilization (figure 2 A). A different type of sediment fills the egg from its damaged portion compared to that surrounding the egg, suggesting that it was buried and fossilized without the pole, thus helping keeping its biological shape intact. The missing pole may also indicate that the egg had hatched, which is independently supported by CT analysis not revealing any embryonic remains. The WDS analysis of the eggshell indicate calcium as the main component of the eggshell crystalline structure, suggesting that diagenetic modifications had been minimal. The egg outer surface is smooth, differing from the undulated and rough surfaces of turtle eggs from the Jurassic of the United States (Bray & Hirsch 1998) and the Cretaceous of Brazil (Azevedo et al. 2000). The eggshell is relatively thin (145–160 µm thick), including the biomineralized layer and an additional cuticle layer of about 7 µm thick (figures 2 B, D–E). Turtle fossil eggshells with a similar thickness are inferred to have either flexible or rigid eggs, e.g. Testudooflexoolithus bathonicae (Hirsh 1996; Bray & Hirsch 1998), Testudoolithus hirschi (Kohring 1999), eggs from the Jurassic of Colorado (Bray & Hirsch 1998), Haininchelys curiosa (Schleich et al. 1988) and Testudinarum ovum (Schleich & Kästle 1988; Schleich et al. 1988). Hirsch (1983) noticed that, along with to the degree of rigidity, eggshell thickness may be ecological and biological indicators. The sea turtle Lepidochelys kempi lays highly pliable eggs, with eggshells about 40 µm thick; the tortoise Geochelone elephantopus lays rigid-shelled eggs, with eggshells about 400 µm thick; the fresh-water turtle Chelydra serpentina has moderately flexible eggs, with 110 µm thick eggshells, although other fresh-water turtles also have rigid eggshells. The Chelydra serpentina condition best compares to that of LPRP-USP 0052, which is congruent with the host freshwater deposits. In addition, the thickness of the additional cuticle layer of LPRP-USP 0052 resembles that of the other freshwater taxon Erymnochelys madagascariensis (Winkler 2006). The functionality of the cuticle layer in turtles is rarely mentioned, however, analogous cuticle structures in bird eggs are directly related to nesting in wet conditions, as described in Megapodiidae, Podicipedidae and Phoenicopteridae, and are thought to preclude the blocking of pores apertures by foreign material to faciliate gas exchange and limit chemical erosion from microorganisms in the soil (Board 1981; Board et al. 1982; Board & Sparks 1991; Booth & Thompson 1991). The outlines of the shell basic units are not easily seen on the outer surface of LPRP-USP 0052 (figure 2 F). Pore openings are very sparse (figure 2 F), a condition also present in the eggs of the extant pleurodires Podocnemis unifilis (Winkler & Sánchez-Villagra 2006), Hydromedusa maximiliani, Phrynops hilarii and Acanthochelys spixii (Winkler 2006). The pores apertures are typical of those seen in podocnemidid eggs, but also of some chelids (Winkler 2006). The diameters range from 76 to 95 µm (figure 2 F and G), differing from the podocnemidids Podocnemis unifilis (pore openings about 27,7 µm wide) and Bairdemys (pores openings about 170 to 200 µm wide, Winkler & Sánchez-Villagra 2006). In radial view, the shell units display the characteristic acicular crystallographic pattern of aragonitic calcium carbonate crystals (figure 2 E), which is considered a Testudines apomorphy (Young 1950; Hirsch 1983, 1996; Packard & Packard 1988; Winkler 2006). The metastable calcium carbonate crystals project radially from the large primary spherites (figure 2 E) differing from the condition in chelids Elseya sp. and Chelus fimbriatus and the podocnemidids Peltocephalus dumerliana and Erymnochelys madagascariensis, with no visible spherites (Winkler 2006). Most shell units of LPRP-USP 0052 are roughly triangular, without marked borders, but more columnar unities are also present. This diversity of shapes results in relatively loosely abutting shell units (figure 2 B, C and E). According to Winkler & Sánchez-Villagra (2006), this allows “caverns” (large inter-units spaces) among shell units in some portions of the eggshell (figure 2, E), which are absent from rigid-shelled eggs, such as those of the podocnemidid Bairdemys (Winkler & Sánchez-Villagra 2006). On the contrary, the semi-flexible egg of Podocnemis unifilis (Foote 1978) has a mix of areas with and without “caverns” (Winkler & Sánchez-Villagra 2006). Finally, shell units of LPRP-USP 0052 are, in average slightly higher than wide (high/width ratio of 1,1–1,2). This is also notable in flexible turtle fossil eggs, as such Testudooflexoolithus bathonicae (Hirsh 1996; Bray & Hirsch 1998) and Testudooflexoolithus agassizi (Hirsch 1996).Published as part of Marsola, Júlio C. De A., Grellet-Tinner, Gerald, Montefeltro, Felipe C. & Langer, Max C., 2014, The first Pan-Podocnemididae turtle egg from the Presidente Prudente Formation (Late Cretaceous, Bauru Group), Brazil, pp. 187-194 in Zootaxa 3872 (2) on pages 189-191, DOI: 10.11646/zootaxa.3872.2.5, http://zenodo.org/record/494804

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

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-

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

Skull of <i>Aplestosuchus sordidus</i> LPRP/USP 0229a in A, dorsal view; and B, ventral.

<p>Abbreviations: a, angular; ap, anterior palpebral; ana, atlantal neural arch; atl, atlas; bo, basioccipital; bs, basisphenoid; cg, choanal groove; d, dentary; d4, dentary tooth 4; ec, ectopterygoid; eo, exoccipital; f, frontal; hy, hyoid aparatus; if, infratemporal fenestra; j, jugal; m, maxilla; m3, maxillary tooth 3; n, nasal; pa, parietal; pf, prefrontal; pl, palatine; pm, premaxilla; po, postorbital; pp, posterior palpebral; pt, pterygoid; q, quadrate; se, choanal septum; sf, supratemporal fenestra; so, supraoccipital; sq, squamosal; sp, splenial; tof, temporo-orbital foramen; III–V cv, cervical vertebrae III–V. Scale bar equals 10 cm.</p