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Dos Santos DM, de Carvalho JC, de Oliveira CEM, de Andrade MB, Santucci RM. Cranial and postcranial anatomy of a juvenile baurusuchid (Notosuchia, Crocodylomorpha) and the taxonomical implications of ontogeny. Anat Rec (Hoboken) 2024. [PMID: 38429867 DOI: 10.1002/ar.25419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 02/16/2024] [Accepted: 02/19/2024] [Indexed: 03/03/2024]
Abstract
Baurusuchidae comprises a clade of top-tier terrestrial predators and are among the most abundant crocodyliforms found in the Adamantina Formation, Bauru Basin, Brazil (Campanian-Maastrichtian). Here, we provide a detailed description of the cranial and postcranial osteology and myology of the most complete juvenile baurusuchid found to date. Although the preservation of juvenile individuals is somewhat rare, previously reported occurrences of baurusuchid egg clutches, a yearling individual, and larger, but skeletally immature specimens, comprise a unique opportunity to track anatomical changes throughout their ontogenetic series. Its cranial anatomy was resolved with the aid of a three-dimensional model generated by the acquisition of computed tomography data, and its inferred adductor mandibular musculature was compared to that of mature specimens in order to assess possible ontogenetic shifts. A subsequent phylogenetic analysis included the scoring of Gondwanasuchus scabrosus, the smallest baurusuchid species known to date, to evaluate its phylogenetic relations relative to a known juvenile. We find considerable differences between juveniles and adults concerning skull ornamentation and muscle development, which might indicate ontogenetic niche partitioning, and also anatomical and phylogenetic evidence that G. scabrosus corresponds to a young semaphoront lacking mature cranial features.
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Affiliation(s)
- Daniel Martins Dos Santos
- Zoology Graduate Program, Institute of Biological Sciences, University of Brasília, Brasília, Brazil
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Pochat‐Cottilloux Y, Rinder N, Perrichon G, Adrien J, Amiot R, Hua S, Martin JE. The neuroanatomy and pneumaticity of Hamadasuchus (Crocodylomorpha, Peirosauridae) from the Cretaceous of Morocco and its paleoecological significance for altirostral forms. J Anat 2023; 243:374-393. [PMID: 37309776 PMCID: PMC10439374 DOI: 10.1111/joa.13887] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 05/03/2023] [Accepted: 05/03/2023] [Indexed: 06/14/2023] Open
Abstract
We describe the endocranial structures of Hamadasuchus, a peirosaurid crocodylomorph from the late Albian-Cenomanian Kem Kem group of Morocco. The cranial endocast, associated nerves and arteries, endosseous labyrinths, and cranial pneumatization, as well as the bones of the braincase of a new specimen, are reconstructed and compared with extant and fossil crocodylomorphs, which represent different lifestyles. Cranial bones of this specimen are identified as belonging to Hamadasuchus, with close affinities with Rukwasuchus yajabalijekundu, another peirosaurid from the 'middle' Cretaceous of Tanzania. The endocranial structures are comparable to those of R. yajabalijekundu but also to baurusuchids and sebecids (sebecosuchians). Paleobiological traits of Hamadasuchus, such as alert head posture, ecology, and behavior are explored for the first time, using quantitative metrics. The expanded but narrow semi-circular canals and enlarged pneumatization of the skull of Hamadasuchus are linked to a terrestrial lifestyle. Continuing work on the neuroanatomy of supposedly terrestrial crocodylomorphs needs to be broadened to other groups and will allow to characterize whether some internal structures are affected by the lifestyle of these organisms.
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Affiliation(s)
| | - Nicolas Rinder
- Univ Lyon, Univ Lyon 1, ENSL, CNRS, LGL‐TPEVilleurbanneFrance
| | | | - Jérôme Adrien
- Laboratoire MatériauxIngénierie et Science, Institut National des Sciences Appliquées de LyonVilleurbanneFrance
| | - Romain Amiot
- Univ Lyon, Univ Lyon 1, ENSL, CNRS, LGL‐TPEVilleurbanneFrance
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Pochat-Cottilloux Y, Martin JE, Amiot R, Cubo J, de Buffrénil V. A survey of osteoderm histology and ornamentation among Crocodylomorpha: A new proxy to infer lifestyle? J Morphol 2023; 284:e21542. [PMID: 36533737 PMCID: PMC10108047 DOI: 10.1002/jmor.21542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 12/23/2022]
Abstract
Osteoderms of eight extant and extinct species of crocodylomorphs are studied histologically and morphologically. Most osteoderms display the typical "crocodilian" structure with a woven-fibered matrix surrounded by an upper and a lower parallel fibered matrix. The dorsal ornamentation of those specimens consists of a pit-and-ridge structure, with corresponding remodeling mechanisms. However, an osteoderm of Iberosuchus, studied here for the first time, differs in being nearly devoid of ornamentation; moreover, it shows strong bundles of straight Sharpey's fibers perpendicular to the surface in its lateral and dorsal walls, along with a rough plywood-like structure in its basal plate. This suggests that this osteoderm was more deeply anchored within the dermis than the other osteoderms studied hitherto. This peculiar structure might have been linked to a terrestrial ecology and a specific thermoregulation strategy. Some other notosuchians in our sample do not exhibit ornamentation on their osteoderms, as opposed to neosuchians. Considering current interpretations of osteoderm function(s) in crocodilians, our observations are discussed in reference to possible ecophysiological peculiarities of Notosuchia in general, and Iberosuchus in particular.
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Affiliation(s)
| | - Jeremy E Martin
- Univ Lyon, Univ Lyon 1, ENSL, CNRS, LGL-TPE, Villeurbanne, France
| | - Romain Amiot
- Univ Lyon, Univ Lyon 1, ENSL, CNRS, LGL-TPE, Villeurbanne, France
| | - Jorge Cubo
- Centre de Recherche en Paléontologie-Paris (CR2P), Sorbonne Université, Paris, France
| | - Vivian de Buffrénil
- Centre de Recherche en Paléontologie-Paris (CR2P), Sorbonne Université, Paris, France
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Young MT, Bowman CIW, Erb A, Schwab JA, Witmer LM, Herrera Y, Brusatte SL. Evidence for a novel cranial thermoregulatory pathway in thalattosuchian crocodylomorphs. PeerJ 2023; 11:e15353. [PMID: 37151298 PMCID: PMC10162039 DOI: 10.7717/peerj.15353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 04/13/2023] [Indexed: 05/09/2023] Open
Abstract
Thalattosuchian crocodylomorphs were a diverse clade that lived from the Early Jurassic to the Early Cretaceous. The subclade Metriorhynchoidea underwent a remarkable transition, evolving from semi-aquatic ambush predators into fully aquatic forms living in the open oceans. Thalattosuchians share a peculiar palatal morphology with semi-aquatic and aquatic fossil cetaceans: paired anteroposteriorly aligned grooves along the palatal surface of the bony secondary palate. In extant cetaceans, these grooves are continuous with the greater palatine artery foramina, arteries that supply their oral thermoregulatory structures. Herein, we investigate the origins of thalattosuchian palatal grooves by examining CT scans of six thalattosuchian species (one teleosauroid, two early-diverging metriorhynchoids and three metriorhynchids), and CT scans of eleven extant crocodylian species. All thalattosuchians had paired osseous canals, enclosed by the palatines, that connect the nasal cavity to the oral cavity. These osseous canals open into the oral cavity via foramina at the posterior terminus of the palatal grooves. Extant crocodylians lack both the external grooves and the internal canals. We posit that in thalattosuchians these novel palatal canals transmitted hypertrophied medial nasal vessels (artery and vein), creating a novel heat exchange pathway connecting the palatal vascular plexus to the endocranial region. Given the general hypertrophy of thalattosuchian cephalic vasculature, and their increased blood flow and volume, thalattosuchians would have required a more extensive suite of thermoregulatory pathways to maintain stable temperatures for their neurosensory tissues.
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Affiliation(s)
- Mark T. Young
- School of GeoSciences, University of Edinburgh, Edinburgh, United Kingdom
- LWL-Museum für Naturkunde, Münster, Germany
| | | | - Arthur Erb
- School of GeoSciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Julia A. Schwab
- School of GeoSciences, University of Edinburgh, Edinburgh, United Kingdom
- Department of Earth and Environmental Sciences, University of Manchester, Manchester, United Kingdom
| | - Lawrence M. Witmer
- Department of Biomedical Sciences, Ohio University, Athens, Ohio, United States
| | - Yanina Herrera
- Museo de La Plata, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, La Plata, Argentina
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Pochat-Cottilloux Y, Martin JE, Jouve S, Perrichon G, Adrien J, Salaviale C, de Muizon C, Cespedes R, Amiot R. The neuroanatomy of Zulmasuchus querejazus (Crocodylomorpha, Sebecidae) and its implications for the paleoecology of sebecosuchians. Anat Rec (Hoboken) 2021; 305:2708-2728. [PMID: 34825786 DOI: 10.1002/ar.24826] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 09/07/2021] [Accepted: 09/29/2021] [Indexed: 01/14/2023]
Abstract
The endocranial structures of the sebecid crocodylomorph Zulmasuchus querejazus (MHNC 6672) from the Lower Paleocene of Bolivia are described in this article. Using computed tomography scanning, the cranial endocast, associated nerves and arteries, endosseous labyrinths, and cranial pneumatization are reconstructed and compared with those of extant and fossil crocodylomorphs, representative of different ecomorphological adaptations. Z. querejazus exhibits an unusual flexure of the brain, pericerebral spines, semicircular canals with a narrow diameter, as well as enlarged pharyngotympanic sinuses. First, those structures allow to estimate the alert head posture and hearing capabilities of Zulmasuchus. Then, functional comparisons are proposed between this purportedly terrestrial taxon, semi-aquatic, and aquatic forms (extant crocodylians, thalattosuchians, and dyrosaurids). The narrow diameter of the semicircular canals but expanded morphology of the endosseous labyrinths and the enlarged pneumatization of the skull compared to other forms indeed tend to indicate a terrestrial lifestyle for Zulmasuchus. Our results highlight the need to gather new data, especially from altirostral forms in order to further our understanding of the evolution of endocranial structures in crocodylomorphs with different ecomorphological adaptations.
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Affiliation(s)
| | - Jeremy E Martin
- Univ Lyon, Univ Lyon 1, ENSL, CNRS, LGL-TPE, Villeurbanne, France
| | - Stéphane Jouve
- Centre de Recherche en Paléontologie - Paris (CR2P), Sorbonne Université, Paris, France
| | | | - Jérome Adrien
- Laboratoire Matériaux, Ingénierie et Science, Institut National des Sciences Appliquées de Lyon, Villeurbanne, France
| | - Céline Salaviale
- Univ Lyon, Univ Lyon 1, ENSL, CNRS, LGL-TPE, Villeurbanne, France
| | - Christian de Muizon
- Centre de Recherche en Paléontologie - Paris (CR2P), Muséum National d'Histoire Naturelle, CNRS/MNHN/Sorbonne Université, Paris, France
| | - Ricardo Cespedes
- Museo de Historia Natural 'Alcide D'Orbigny', Cochabamba, Bolivia
| | - Romain Amiot
- Univ Lyon, Univ Lyon 1, ENSL, CNRS, LGL-TPE, Villeurbanne, France
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Nicholl CSC, Hunt ESE, Ouarhache D, Mannion PD. A second peirosaurid crocodyliform from the Mid-Cretaceous Kem Kem Group of Morocco and the diversity of Gondwanan notosuchians outside South America. ROYAL SOCIETY OPEN SCIENCE 2021; 8:211254. [PMID: 34659786 PMCID: PMC8511751 DOI: 10.1098/rsos.211254] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/13/2021] [Indexed: 05/04/2023]
Abstract
Notosuchians are an extinct clade of terrestrial crocodyliforms with a particularly rich record in the late Early to Late Cretaceous (approx. 130-66 Ma) of Gondwana. Although much of this diversity comes from South America, Africa and Indo-Madagascar have also yielded numerous notosuchian remains. Three notosuchian species are currently recognized from the early Late Cretaceous (approx. 100 Ma) Kem Kem Group of Morocco, including the peirosaurid Hamadasuchus rebouli. Here, we describe two new specimens that demonstrate the presence of at least a fourth notosuchian species in this fauna. Antaeusuchus taouzensis n. gen. n. sp. is incorporated into one of the largest notosuchian-focused character-taxon matrices yet to be compiled, comprising 443 characters scored for 63 notosuchian species, with an increased sampling of African and peirosaurid species. Parsimony analyses run under equal and extended implied weighting consistently recover Antaeusuchus as a peirosaurid notosuchian, supported by the presence of two distinct waves on the dorsal dentary surface, a surangular which laterally overlaps the dentary above the mandibular fenestra, and a relatively broad mandibular symphysis. Within Peirosauridae, Antaeusuchus is recovered as the sister taxon of Hamadasuchus. However, it differs from Hamadasuchus with respect to several features, including the ornamentation of the lateral surface of the mandible, the angle of divergence of the mandibular rami, the texture of tooth enamel and the shape of the teeth, supporting their generic distinction. We present a critical reappraisal of the non-South American Gondwanan notosuchian record, which spans the Middle Jurassic-late Eocene. This review, as well as our phylogenetic analyses, indicate the existence of at least three approximately contemporaneous peirosaurid lineages within the Kem Kem Group, alongside other notosuchians, and support the peirosaurid affinities of the 'trematochampsid' Miadanasuchus oblita from the Maastrichtian of Madagascar. Furthermore, the Cretaceous record demonstrates the presence of multiple lineages of approximately contemporaneous notosuchians in several African and Madagascan faunas, and supports previous suggestions regarding an undocumented pre-Aptian radiation of Notosuchia. By contrast, the post-Cretaceous record is depauperate, comprising rare occurrences of sebecosuchians in north Africa prior to their extirpation.
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Affiliation(s)
- Cecily S. C. Nicholl
- Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK
| | - Eloise S. E. Hunt
- Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK
- Science and Solutions for a Changing Planet DTP, and the Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Driss Ouarhache
- Laboratoire Géosystèmes, Environnement et Développement Durable, Département de Géologie, Faculté des Sciences Dhar El Mahraz, Université Sidi Mohamed Ben Abdellah, BP 1796, Atlas 30 000, Fès, Morocco
| | - Philip D. Mannion
- Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK
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Pinheiro AEP, Souza LGDE, Bandeira KLN, Brum AS, Pereira PVLGC, Castro LORDE, Ramos RRC, Simbras FM. The first notosuchian crocodyliform from the Araçatuba Formation (Bauru Group, Paraná Basin), and diversification of sphagesaurians. AN ACAD BRAS CIENC 2021; 93:e20201591. [PMID: 34161450 DOI: 10.1590/0001-3765202120201591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Accepted: 04/01/2021] [Indexed: 11/21/2022] Open
Abstract
The mesoeucrocodylian record from the Bauru Group (Paraná Basin, Brazil) comes from three formations: Adamantina (Late Turonian-Early Maastrichtian), Presidente Prudente (Early Campanian-Early Maastrichtian) and Marília (Maastrichtian). These records are restricted to the Early Coniacian-Early Maastrichtian. Here, we report a new crocodyliform record from the Bauru Group, which was the first of the Araçatuba Formation, from a new locality of Coronel Goulart district, in Álvares Machado municipality. Coronelsuchus civali gen. nov. et sp. nov. comprises two related specimens - FFP PG 13 and FFP PG 14 recovered close to each other and on the same muddy sandstone level. We perform a phylogenetic analysis with 392 characters (five new added) and 88 taxa. Our analyses supported the new clades: Sphagesauria, Sphagesaurinae and Caipirasuchinae. Our phylogenetic results suggest C. civali as a basal Sphagesauria. Regarding the Crocodyliform Assemblage Zones (CAZ), the new species is correlated to the CAZ 1, together with small sphagesaurians, Caryonosuchus and itasuchids. The C. civali reveals an older appearing (pre-Turonian) and diversification of Sphagesauria. The specimens also expand the stratigraphic range for Notosuchia in the Bauru Group.
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Affiliation(s)
- André Eduardo P Pinheiro
- Universidade do Estado do Rio de Janeiro, Departamento de Ciências, Faculdade de Formação de Professores (UERJ/DCIEN/FFP), R. Francisco Portela, 1470, Patronato, 24435-005 São Gonçalo, RJ Brazil
| | - Lucy G DE Souza
- Universidade Federal do Acre, Museu da Amazônia (UFAC/MUSA), Av. Margarida, 6305, Jorge Teixeira, 69088-265 Manaus, AM, Brazil
| | - Kamila L N Bandeira
- Universidade Federal do Rio de Janeiro, Departamento de Geologia e Paleontologia, Museu Nacional, (UFRJ/DGP/MN), Quinta da Boa Vista, s/n, São Cristóvão, 20940-040 Rio de Janeiro, RJ, Brazil
| | - Arthur S Brum
- Universidade Federal do Rio de Janeiro, Departamento de Geologia e Paleontologia, Museu Nacional, (UFRJ/DGP/MN), Quinta da Boa Vista, s/n, São Cristóvão, 20940-040 Rio de Janeiro, RJ, Brazil
| | - Paulo Victor Luiz G C Pereira
- Universidade Federal of Rio de Janeiro, Departamento de Geologia, Instituto de Geociências, (UFRJ/DEGEO/IGEO), Av. Athos da Silveira Ramos 274, Prédio CCMN, 21941-611 Rio de Janeiro, RJ, Brazil
| | - Luís Otávio R DE Castro
- Universidade Federal of Rio de Janeiro, Departamento de Geologia, Instituto de Geociências, (UFRJ/DEGEO/IGEO), Av. Athos da Silveira Ramos 274, Prédio CCMN, 21941-611 Rio de Janeiro, RJ, Brazil
| | - Renato R C Ramos
- Universidade Federal do Rio de Janeiro, Departamento de Geologia e Paleontologia, Museu Nacional, (UFRJ/DGP/MN), Quinta da Boa Vista, s/n, São Cristóvão, 20940-040 Rio de Janeiro, RJ, Brazil
| | - Felipe M Simbras
- Universidade Federal Rural de Pernambuco (UFRPE), Departamento de Biologia, R. Dom Manuel de Medeiros, s/n, Dois Irmãos, 52171-900 Recife, PE, Brazil
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Iijima M, Kubo T. Vertebrae-Based Body Length Estimation in Crocodylians and Its Implication for Sexual Maturity and the Maximum Sizes. Integr Org Biol 2020; 2:obaa042. [PMID: 33791579 PMCID: PMC7891683 DOI: 10.1093/iob/obaa042] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Body size is fundamental to the physiology and ecology of organisms. Crocodyliforms are no exception, and several methods have been developed to estimate their absolute body sizes from bone measurements. However, species-specific sizes, such as sexually mature sizes and the maximum sizes were not taken into account due to the challenging maturity assessment of osteological specimens. Here, we provide a vertebrae-based method to estimate absolute and species-specific body lengths in crocodylians. Lengths of cervical to anterior caudal centra were measured and relations between the body lengths (snout-vent and total lengths [TLs]) and lengths of either a single centrum or a series of centra were modeled for extant species. Additionally, states of neurocentral (NC) suture closure were recorded for the maturity assessment. Comparisons of TLs and timings of NC suture closure showed that most extant crocodylians reach sexual maturity before closure of precaudal NC sutures. Centrum lengths (CLs) of the smallest individuals with closed precaudal NC sutures within species were correlated with the species maximum TLs in extant taxa; therefore, the upper or lower limit of the species maximum sizes can be determined from CLs and states of NC suture closure. The application of the current method to noncrocodylian crocodyliforms requires similar numbers of precaudal vertebrae, body proportions, and timings of NC suture closure as compared to extant crocodylians.
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Affiliation(s)
- Masaya Iijima
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
- Nagoya University Museum, Furocho, Chikusa-Ku, Nagoya, Aichi 464-8601, Japan
- Engineering Research Center for Mineral Resources and Mine Environments, School of Resource and Environmental Engineering, Hefei University of Technology, 193 Tunxi Road, Baohe, Hefei, Anhui 230009, China
| | - Tai Kubo
- The University Museum, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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