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A new crocodilian from the Lower Cretaceous Crato Formation of north-eastern Brazil

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Abstract

A new mesosuchian crocoddian from the Nova Olinda Member of the Crato Formation (Lower Cretaceous, Aptian) of north-eastern Brazil is described. Susisuchus anatoceps gen. et sp. nov. is the first crocodillan to be reported from this formation. It is represented by an incomplete, partially articulated skeleton: the skull and mandible, partial postcranial axial skeleton, forelimbs and portions of the osteodermal skeleton. Preservation of soft tissues includes the skin surrounding both forelimbs and the digits of the right hand. The state of preservation of the specimen suggests that it was incorporated into the basin as a desiccated carcass. Susisuchus anatoceps is one of the oldest crocodilians with a eusuchian-type dorsal shield, comprising a tetraserial paravertebral shield and, either side of this, two sagittal rows of accessory osteoderms. It also possesses amphicoelous thoracic, lumbar and caudal vertebrae. This combination of postcranial features have never before been seen in a crocodilian and warrant the erection of a new family within Mesosuchia: Susisuchidae. Taxonomically, S. anatoceps is similar to a number of Lower Cretaceous mesosuchians previously considered to have given rise to eusuchians, most notably the Glen Rose crocodilian and a new, but as yet undescribed crocodillan from the Lower Cretaceous Winton Formation of western Queensland, Australia. Preliminary preparation of the Winton crocodilian indicates that it may belong to Susisuchidae, supporting the hypotheses of interchange between the vertebrate faunas of South America and Australia during the Lower Cretaceous.
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... The only other crocodyliform material from the Mesozoic of Australia comes from the Aptian-Albian Otway Formation of Victoria and includes isolated osteoderms, vertebrae, and a quadratojugal (see Poropat et al., 2018). Salisbury et al. (2003) suggested this material might pertain to a susisuchid, indicating a close relationship to Isisfordia (Turner and Pritchard, 2015;Montefeltro et al., 2020). ...
... Quadrate.-Although the articular condyles of AM F66766 (Fig. 5.6, 5.7) as discussed in the preceding differ from the condition seen in I. duncani, intraspecific variation (such as other features seen on AM F125553, the braincase assigned to I. molnari, [see Hart et al., 2019]) cannot be ruled out, especially considering the articular condyles of the quadrate preserved in AM F125553 are incomplete. The quadrate is superficially similar to the susisuchids Susisuchus anatoceps Salisbury et al., 2003and Susisuchus jaguarbiensis Fortier and Schultz, 2009(Salisbury et al., 2003Fortier and Schultz, 2009;Leite and Fortier, 2018). As Isisfordia is the only known susisuchid-grade crocodyliform from the Griman Creek Formation, it is reasonable to assume that AM F66766 pertains to this genus. ...
... Quadrate.-Although the articular condyles of AM F66766 (Fig. 5.6, 5.7) as discussed in the preceding differ from the condition seen in I. duncani, intraspecific variation (such as other features seen on AM F125553, the braincase assigned to I. molnari, [see Hart et al., 2019]) cannot be ruled out, especially considering the articular condyles of the quadrate preserved in AM F125553 are incomplete. The quadrate is superficially similar to the susisuchids Susisuchus anatoceps Salisbury et al., 2003and Susisuchus jaguarbiensis Fortier and Schultz, 2009(Salisbury et al., 2003Fortier and Schultz, 2009;Leite and Fortier, 2018). As Isisfordia is the only known susisuchid-grade crocodyliform from the Griman Creek Formation, it is reasonable to assume that AM F66766 pertains to this genus. ...
Article
The sparse record of Cretaceous crocodyliforms in Australia comprises only three species, all within the genus Isisfordia. Isisfordia duncani Salisbury et al., 2006 is from the Albian-Turonian Winton Formation of Queensland, and both Isisfordia molnari Hart et al., 2019 and Isisfordia selaslophensis Etheridge, 1917 have been described from opalized material from the Cenomanian Griman Creek Formation of New South Wales. Here, we describe new cranial and postcranial material, including the most complete crocodyliform skeleton from the Cretaceous of New South Wales, which is assigned to Isisfordia cf. I. selaslophensis. We also reappraise previously described crocodyliform material from the same locality. We find that much of this material displays features that are consistent with Isisfordia.
... Currently, the law in force is The Federal Law of Archaeological, Artistic and Historic Monuments and Zones, published in 1972 [46]. The Instituto Nacional de Antropología e Historia, [26], ( publication retracted by publisher), (b) SMNK PAL 3828, holotype of the pterosaur Ludodactylus sibbicki [28], (c) SMNK 2344 PAL holotype of the pterosaur Tupandactylus navigans [95], (d ) SMNS 58022 holotype of the dinosaur Irritator challengeri [30] (e) SMNK PAL 3804, holotype of the crocodyliform Susisuchus anatoceps [96], ( f ) private collection BMMS BK 2-2, holotype of the putative legged-snake Tetrapodophis amplectus [27], currently interpreted as an aquatic lizard [33], photograph by Michael Caldwell. Abbreviations: SMNK, State Museum of Natural History Karlsruhe, Germany; SMNS, State Museum of Natural History Stuttgart. ...
... This fact, together with the absence of reported exportation permits, leads us to consider that these fossils may have been purchased (figure 5). Some publications state that the fossils were 'obtained from a quarry workman' [92] or 'from a fossil digger' [93] and eight publications [28,30,[94][95][96][97][98][99] directly acknowledge that the specimen was purchased. ...
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Scientific practices stemming from colonialism, whereby middle- and low-income countries supply data for high-income countries and the contributions of local expertise are devalued, are still prevalent today in the field of palaeontology. In response to these unjust practices, countries such as Mexico and Brazil adopted protective laws and regulations during the twentieth century to preserve their palaeontological heritage. However, scientific colonialism is still reflected in many publications describing fossil specimens recovered from these countries. Here, we present examples of ‘palaeontological colonialism’ from publications on Jurassic–Cretaceous fossils from NE Mexico and NE Brazil spanning the last three decades. Common issues that we identified in these publications are the absence of both fieldwork and export permit declarations and the lack of local experts among authorships. In Mexico, access to many fossil specimens is restricted on account of these specimens being housed in private collections, whereas a high number of studies on Brazilian fossils are based on specimens illegally reposited in foreign collections, particularly in Germany and Japan. Finally, we outline and discuss the wider academic and social impacts of these research practices, and propose exhaustive recommendations to scientists, journals, museums, research institutions and government and funding agencies in order to overcome these practices.
... Due to the smaller size of the Arenysuchus holotype (MPZ 2011/184) compared to other allodaposuchids, this low REQ could also be related to the possibility that this specimen might be a juvenile (e.g., Narv aez, 2015;Narv aez et al., 2015). There are a series of cranial characters recognizable in MPZ 2011/184 that have been related with juvenile specimens in extant crocodylians (Salisbury et al., 2003;De Buffr enil et al., 2015;Bailleul et al., 2016;Sayão et al., 2016;Fern andez Blanco et al., 2018): relatively short snout and big skull table; big orbits and supratemporal fossae; 'closed' sutures (sensu Bailleul et al., 2016); concave frontal between the orbits; and feeble ornamentation. However, it has been observed that many of these juvenile characters also appear in adult individuals of dwarf crocodylian species (Salisbury et al., 2003;Sayão et al., 2016). ...
... There are a series of cranial characters recognizable in MPZ 2011/184 that have been related with juvenile specimens in extant crocodylians (Salisbury et al., 2003;De Buffr enil et al., 2015;Bailleul et al., 2016;Sayão et al., 2016;Fern andez Blanco et al., 2018): relatively short snout and big skull table; big orbits and supratemporal fossae; 'closed' sutures (sensu Bailleul et al., 2016); concave frontal between the orbits; and feeble ornamentation. However, it has been observed that many of these juvenile characters also appear in adult individuals of dwarf crocodylian species (Salisbury et al., 2003;Sayão et al., 2016). On the contrary, other characters indicating a higher degree of ontogenetic development are also present in MPZ 2011/184: relatively big pterygoid flanges and small internal choana; subcircular supratemporal fossae (usually more elliptical and obliquely oriented in juveniles); and cranial table with straight margins and long squamosal prongs. ...
Article
The South Pyrenean Basin (northeast Spain) has yielded a rich and diverse collection of vertebrate fossil remains from the uppermost Cretaceous (upper Maastrichtian), amongst which Crocodylomorpha is one of the best represented clades. This record includes remains of the last representatives of the basal eusuchian clade Allodaposuchidae prior to its disappearance after the Cretaceous-Paleogene (K/Pg) extinction event. In this context, the holotype skulls of the allodaposuchids Arenysuchus gascabadiolorum and Agaresuchus subjuniperus were CT scanned to obtain the three-dimensional reconstruction of their inner cranial cavities, including the brain, nerves, blood vessels, paratympanic sinus system, and the paranasal sinuses. These cavities were compared with those of other crocodylomorphs, with special emphasis on other allodaposuchids and related clades such as Crocodylia. The endocranial anatomy of both taxa is consistent with their phylogenetic position as basal eusuchians, showing morphologies and neurosensorial and cognitive capabilities similar to those present in other allodaposuchids. Their inferred sensorial capabilities, such as an acute sense of olfaction and relatively good sight, fall within the range observed in most eusuchians and the crown group Crocodylia, suggesting that the sensory and cognitive skills observed in extant crocodylians were already similar at the end of the Mesozoic. Thanks to this study, all the known genera of Allodaposuchidae now have reconstructions of their inner skull cavities, making this clade one of the neuroanatomically best-studied groups among Neosuchia, providing valuable information on the neurological and neurosensorial evolution of the basal eusuchians and the early radiation of Crocodylia.
... Kischlat and Campos (1990) suggested that Araripemys was more aquatic in its habit than living pleurodires. Only two species of crocodilians are recorded for the Crato Fm.: Araripesuchus gomesi Price (1959) and Susisuchus anatoceps Salisbury et al. (2003). The A. gomesi is a crocodilian presumably terrestrial. ...
... The A. gomesi is a crocodilian presumably terrestrial. S. anatoceps should reach~1 m in length and feed on small prey such as crustaceans, fishes, and insects (Salisbury et al. 2003). Presumably, the hypersaline conditions of the Crato palaeolake prevented S.anatoceps from spending much time hunting in the water. ...
Chapter
The fossil record is uninformative concerning the habits and lifestyles of extinct organisms. Living species are positioned within a trophic hierarchy, presumably extinct taxa were susceptible to the same kind of environmental pressures operating today. In the past, the organisms held similar behavioral and evolutionary dynamics, but the paleoecological investigations are limited by the incompleteness of the fossil record. So, the opportunities to exanimate the structure of ancient ecosystem are extremely rare. The Cretaceous Crato Formation, northeastern Brazil, offers one of these opportunities. Crato fossils provide essential evidence for understanding major issues regarding evolution and paleoecology of this ancient ecosystem. The Crato Fm. deposition took place under anoxic and hypersaline bottom water conditions, as evidenced by the virtually undisturbed lamination pattern, the occurrence of halite pseudomorphs and by the absence of a benthonic fauna. These particular paleoenvironmental conditions made it possible to preserve an exceptional fauna and flora with fine details and even labile tissues. The fossil fauna and flora of the Crato limestone are considered to be predominantly allochthonous. Despite the high-fidelity preservation, the fossils are remarkable for their concentrated abundance as well as for their diversity. Therefore, understanding the trophic hierarchy of these organisms has already provided many important insights into the Early Cretaceous low-latitude Crato biome.
... The shoulder girdle of Confractosuchus closely resembles Anteophthalmosuchus hooleyi (see fig. 16 in (Martin Delfino and Smith, 2016)). Anteophthalmosuchus shoulder girdle morphology was reported to be similar to Isisfordia duncani (scapula only see fig. 2 in Salisbury et al. (2006) and Susisuchus anatoceps (schematic outline, see fig. 3 in Salisbury et al. (2003); however, the published images of both these susisuchids were insufficient to draw such similarities to Confractosuchus. A resemblance with Pachycheilosuchus trinquei (Rogers, 2003) can be established despite a slightly different orientation in the figures and only one view supplied of each (see fig. 6A,B in Rogers (2003)). ...
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Crocodylians are among Earth’s most successful hyper-carnivores, with their crocodyliform ancestors persisting since the Triassic. The diets of extinct crocodyliforms are typically inferred from distinctive bite-marks on fossil bone, which indicate that some species fed on contemporaneous dinosaurs. Nevertheless, the most direct dietary evidence (i.e. preserved gut contents) of these interactions in fossil crocodyliforms has been elusive. Here we report on a new crocodyliform, Confractosuchus sauroktonos gen. et sp. nov., from the Cenomanian (92.5–104 Ma) of Australia, with exceptionally preserved abdominal contents comprising parts of a juvenile ornithopod dinosaur. A phylogenetic analysis recovered Confractosuchus as the sister taxon to a clade comprising susisuchids and hylaeochampsids. The ornithopod remains displayed clear evidence of oral processing, carcass reduction (dismemberment) and bone fragmentation, which are diagnostic hallmarks of some modern crocodylian feeding behaviour. Nevertheless, a macro-generalist feeding strategy for Confractosuchus similar to extant crocodylians is supported by a morphometric analysis of the skull and reveals that dietary versatility accompanied the modular assembly of the modern crocodylian bauplan. Of further interest, these ornithopod bones represent the first skeletal remains of the group from the Winton Formation, previously only known from shed teeth and tracks, and may represent a novel taxon.
... Although present, juvenile crocodylomorph individuals are rare in the Brazilian fossil record, and none of the known specimens are considered yearlings (Salisbury et al. 2003;Figueiredo and Kellner 2009;Geroto and Bertini 2012;Godoy et al. 2018). Nevertheless, semaphoronts comprise an important Institution abbreviations IFSP-VTP -Federal Institute of Education, Science and Technology of São Paulo, Votuporanga Campus. ...
Article
Occurrences of young and immature individuals, relatively rare in the fossil record, are important due to the great amount of morphological and evolutionary information they reveal about a lineage’s development. Although crocodylomorphs are the most abundant terrestrial vertebrates found in the Bauru Basin, southeastern Brazil, even outnumbering dinosaurian materials, much remains to be understood about their anatomy, ecology, and ontogeny. Egg fragments, nests and nesting sites attributed to Baurusuchus have been previously described, but unfortunately none of these yielded embryonic or hatchling remains. Here, we describe, for the first time, skeletal material of a small notosuchian yearling, recovered from the Adamantina Formation, with osteological features consistent with a baurusuchid affinity. We provide and discuss osteological and histological evidence of its ontogenetic stage, revealing morphological characters distinct from most adult forms, including conspicuous centro-parapophyseal laminae and developed ventral keels. Computerised tomography data also allowed for the identification of incipient ossification and a novel ontogenetic feature in the diminishing volume of the frontal´s internal recesses. Similar materials will increase our understanding of notosuchian ontogeny and diversity, thus requiring growth characters to be integrated into future phylogenies.
... Within Mesoeucrocodylia, the information about long bone histology is scarce and most of these works are focused on neosuchians (e.g. dyrosaurids and eusuchians as Susisuchus anatoceps Salisbury et al., 2003;Leidyosuchus Lambe, 1907;Alligator mississippiensis Daudin, 1801;Crocodylus Laurenti, 1768;Gavialis gangeticus Gmelin, 1789;Caiman Spix, 1825;see Peabody 1961;Wink et al. 1987;Castanet 1994;Lee 2004;Schweitzer et al. 2007;Tumarkin-Deratzian 2007;Klein et al. 2009;Garcia 2011;Woodward et al. 2011Woodward et al. , 2014Werning 2013;de Andrade & Sayão 2014;Andrade et al. 2015Andrade et al. , 2018Sayão et al. 2016;Sena et al. 2018). Osteohistological studies carried out in crocodylians show a preponderance of a slow growth bone matrix pattern. ...
Article
Notosuchian crocodyliforms represent an intriguing group since they are mainly terrestrial forms and therefore with completely different lifestyles than extant crocodylian, which is reflected in their particular skeletal anatomy. Although there are some inferences in the literature related to the palaeoecology of notosuchian, little is known about their biology (e.g. metabolism, growth dynamics). The palaeohistology allows us to perform interpretations about the growth dynamics and strategies of growth in these extinct forms. Here, we worked on specimens of Araripesuchus Price, 1959 (Notosuchia, Uruguaysuchidae), coming from La Buitrera Palaeontological Area, Río Negro Province (northern Patagonia, Argentina). We described for the first time the osteohistology of this taxon, based on thin sections of the stylopodium shaft (femur and humerus) of four specimens, providing an assumption of its growth dynamics. A general slow growth rate is inferred for Araripesuchus, based on the poorly vascularized parallel‐fibred/lamellar bone matrix. An unusual pattern of bone deposition was observed in two specimens; we consider this tissue as evidence of a rapid growth event at some point in the ontogeny of these individuals. Finally, it can be interpreted that in Araripesuchus, sexual maturity could be reached at least between eight to thirteen years old. This study is a first step to provide insight into the life history of these terrestrial notosuchids and to provide new empirical evidence for the osteohistological variability and palaeoecology of this peculiar group of extinct crocodyliforms.
... The supratemporal fenestra (=dorsotemporal or upper temporal fenestra; supratemporal foramen of Salisbury et al., 2003) on the left side is complete, whereas the right fenestra preserves only its anterior and anteromedial margins (Figs. 16,17,19,20 very small relative to the cranial table (~27 mm in length as measured along anterior margin;~44 mm in length as measured along medial margin;~32 mm in length as measured along lateral margin) and irregularly shaped, appearing in the form of the letter D (character 207, state 5). ...
Article
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The crocodylian fossil record from the Cenozoic of Australasia is notable for its rich taxonomic diversity, and is primarily represented by members of the clade Mekosuchinae. Reports of crocodylian fossils from Australia date back to the late nineteenth century. In 1886, Charles Walter de Vis proposed the name Pallimnarchus pollens for crocodylian fossils from southeast Queensland—the first binomen given to an extinct crocodylian taxon from Australia. Pallimnarchus has come to be regarded as a large, broad-snouted crocodylian from Australia’s Plio-Pleistocene, and numerous specimens, few of which are sufficiently complete, have been assigned to it by several authors throughout the twentieth century. In the late 1990s, the genus was expanded to include a second species, Pallimnarchus gracilis. Unfortunately, the original syntype series described as Pallimnarchus pollens is very fragmentary and derives from more than one taxon, while a large part of the subsequently selected lectotype specimen is missing. Because descriptions and illustrations of the complete lectotype do not reveal any autapomorphic features, we propose that Pallimnarchus pollens should be regarded as a nomen dubium. Following this decision, the fossil material previously referred to Pallimnarchus is of uncertain taxonomic placement. A partial skull, formerly assigned to Pallimnarchus pollens and known as ‘Geoff Vincent’s specimen’, possesses many features of diagnostic value and is therefore used as basis to erect a new genus and species—Paludirex vincenti gen. et sp. nov. A comprehensive description is given for the osteology of ‘Geoff Vincent’s specimen’ as well as aspects of its palaeoneurology, the latter being a first for an extinct Australian crocodyliform. The newly named genus is characterized by a unique combination of premaxillary features such as a distinctive arching of the anterior alveolar processes of the premaxillae, a peculiar arrangement of the first two premaxillary alveoli and a large size disparity between the 3rd and 4th premaxillary alveoli. These features presently allow formal recognition of two species within the genus, Paludirex vincenti and Paludirex gracilis comb. nov., with the former having comparatively more robust rostral proportions than the latter. The Paludirex vincenti holotype comes from the Pliocene Chinchilla Sand of the Darling Downs, south-eastern Queensland, whereas the material assigned to Paludirex gracilis is from the Pleistocene of Terrace Site Local Fauna, Riversleigh, northwest Queensland. Phylogenetic analyses recover Paludirex vincenti as a mekosuchine, although further cladistic assessments are needed to better understand the relationships within the clade.
... Note that phylogenetic positions of many clades are still under debate (Pu ertolas-Pascual et al. 2020). Literature for vertebral counts of each clade: Paralligatoridae (Wu, Cheng, et al. 2001;Pol et al. 2009); Bernissartiidae (Norell and Clark 1990); Goniopholididae (Wu et al. 1996;Lauprasert et al. 2007;Erickson 2016;Martin et al. 2016; GMNH-PV0000229); Susisuchidae (Salisbury et al. 2003(Salisbury et al. , 2006Figueiredo et al. 2011); Tethysuchia (Troxell 1925b;Storrs 1986;Langston 1995;Jouve and Schwarz 2004;Jouve et al. 2006;Schwarz et al. 2006); Atoposauridae (Wellnhofer 1971;Buscalioni and Sanz 1990;Michard et al. 1990;Storrs and Efimov 2000;Tennant et al. 2016); Notosuchia (Pol 2005;Turner 2006;Fiorelli and Calvo 2008;Sereno and Larsson 2009;Georgi and Krause 2010;Nascimento and Zaher 2010;O'Connor et al. 2010;Nobre and de Souza Carvalho 2013;Leardi et al. 2015;Martinelli et al. 2018); Protosuchia (Colbert and Mook 1951;Li 1985;Wu et al. 1994;Peng 1996;Osm olska et al. 1997;Pol and Norell 2004;Peng and Shu 2005). See Supplementary data, Table S3 for vertebral counts for each species. ...
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