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Burke PMJ, Mannion PD. Neuroanatomy of the crocodylian Tomistoma dowsoni from the Miocene of North Africa provides insights into the evolutionary history of gavialoids. J Anat 2023; 243:1-22. [PMID: 36929596 PMCID: PMC10273334 DOI: 10.1111/joa.13846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 01/24/2023] [Accepted: 01/24/2023] [Indexed: 03/18/2023] Open
Abstract
The interrelationships of the extant crocodylians Gavialis gangeticus and Tomistoma schlegelii have been historically disputed. Whereas molecular analyses indicate a sister taxon relationship between these two gavialoid species, morphological datasets typically place Gavialis as the outgroup to all other extant crocodylians. Recent morphological-based phylogenetic analyses have begun to resolve this discrepancy, recovering Gavialis as the closest living relative of Tomistoma; however, several stratigraphically early fossil taxa are recovered as closer to Gavialis than Tomistoma, resulting in anomalously early divergence timings. As such, additional morphological data might be required to resolve these remaining discrepancies. 'Tomistoma' dowsoni is an extinct species of gavialoid from the Miocene of North Africa. Utilising CT scans of a near-complete, referred skull, we reconstruct the neuroanatomy and neurosensory apparatus of 'Tomistoma' dowsoni. Based on qualitative and quantitative morphometric comparisons with other crocodyliforms, the neuroanatomy of 'Tomistoma' dowsoni is characterised by an intermediate morphology between the two extant gavialoids, more closely resembling Gavialis. This mirrors the results of recent studies based on the external anatomy of these three species and other fossil gavialoids. Several neuroanatomical features of these species appear to reflect ecological and/or phylogenetic signals. For example, the 'simple' morphology of their neurosensory apparatus is broadly similar to that of other long and narrow-snouted (longirostrine), aquatic crocodyliforms. A dorsoventrally short, anteroposteriorly long endosseous labyrinth is also associated with longirostry. These features indicate that snout and skull morphology, which are themselves partly constrained by ecology, exert an influence on neuroanatomical morphology, as has also been recognised in birds and turtles. Conversely, the presence of a pterygoid bulla in Gavialis and several extinct gavialoids, and its absence in Tomistoma schlegelii, could be interpreted as a phylogenetic signal of crocodylians more closely related to Gavialis than to Tomistoma. Evaluation of additional fossil gavialoids will be needed to further test whether these and other neuroanatomical features primarily reflect a phylogenetic or ecological signal. By incorporating such previously inaccessible information of extinct and extant gavialoids into phylogenetic and macroecological studies, we can potentially further constrain the clade's interrelationships, as well as evaluate the timing and ecological association of the evolution of these neuroanatomical features. Finally, our study supports recent phylogenetic analyses that place 'Tomistoma' dowsoni as being phylogenetically closer to Gavialis gangeticus than to Tomistoma schlegelii, indicating the necessity of a taxonomic revision of this fossil species.
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2
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Perrichon G, Hautier L, Pochat-Cottilloux Y, Raselli I, Salaviale C, Dailh B, Rinder N, Fernandez V, Adrien J, Lachambre J, Martin JE. Ontogenetic variability of the intertympanic sinus distinguishes lineages within Crocodylia. J Anat 2023; 242:1096-1123. [PMID: 36709416 PMCID: PMC10184552 DOI: 10.1111/joa.13830] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 01/10/2023] [Accepted: 01/10/2023] [Indexed: 01/30/2023] Open
Abstract
The phylogenetic relationships within crown Crocodylia remain contentious due to conflicts between molecular and morphological hypotheses. However, morphology-based datasets are mostly constructed on external characters, overlooking internal structures. Here, we use 3D geometric morphometrics to study the shape of the intertympanic sinus system in crown crocodylians during ontogeny, in order to assess its significance in a taxonomic context. Intertympanic sinus shape was found to be highly correlated with size and modulated by cranial shape during development. Still, adult sinus morphology distinguishes specimens at the family, genus and species level. We observe a clear distinction between Alligatoridae and Longirostres, a separation of different Crocodylus species and the subfossil Malagasy genus Voay, and a distinction between the Tomistoma and Gavialis lineages. Our approach is independent of molecular methods but concurs with the molecular topologies. Therefore, sinus characters could add significantly to morphological datasets, offering an alternative viewpoint to resolve problems in crocodylian relationships.
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Affiliation(s)
- Gwendal Perrichon
- CNRS UMR 5276, Université Claude Bernard Lyon 1, ENS de Lyon, Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement, Villeurbanne, France
| | - Lionel Hautier
- Institut des Sciences de l'Évolution, Université Montpellier, CNRS, IRD, EPHE, Montpellier, France.,Mammal Section, Life Sciences, Vertebrate Division, The Natural History Museum, London, UK
| | - Yohan Pochat-Cottilloux
- CNRS UMR 5276, Université Claude Bernard Lyon 1, ENS de Lyon, Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement, Villeurbanne, France
| | - Irena Raselli
- Geoscience Department, Chemin de Musée 6, University of Fribourg, Jurassica Museum, Porrentruy, Switzerland
| | - Céline Salaviale
- CNRS UMR 5276, Université Claude Bernard Lyon 1, ENS de Lyon, Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement, Villeurbanne, France
| | - Benjamin Dailh
- CNRS UMR 5276, Université Claude Bernard Lyon 1, ENS de Lyon, Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement, Villeurbanne, France
| | - Nicolas Rinder
- CNRS UMR 5276, Université Claude Bernard Lyon 1, ENS de Lyon, Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement, Villeurbanne, France
| | | | - Jérôme Adrien
- Laboratoire Matériaux, Ingénierie et Science, Institut National des Sciences Appliquées de Lyon, Villeurbanne, France
| | - Joël Lachambre
- Laboratoire Matériaux, Ingénierie et Science, Institut National des Sciences Appliquées de Lyon, Villeurbanne, France
| | - Jeremy E Martin
- CNRS UMR 5276, Université Claude Bernard Lyon 1, ENS de Lyon, Laboratoire de Géologie de Lyon: Terre, Planètes, Environnement, Villeurbanne, France
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3
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Boerman SA, Perrichon G, Yang J, Li CS, Martin JE, Speijer RP, Smith T. A juvenile skull from the early Palaeocene of China extends the appearance of crocodyloids in Asia back by 15–20 million years. Zool J Linn Soc 2022. [DOI: 10.1093/zoolinnean/zlac067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
The earliest Crocodylia from Asia have been represented so far only by alligatoroids and planocraniids. Although definitive crocodyloids are not known until the late Eocene, it has been hypothesized that Asiatosuchus-like basal crocodyloids originated in Asia before the late Palaeocene. In this paper, we describe a new fossil crocodyloid from the lower Palaeocene of Qianshan Basin, Anhui Province, China. The skull and lower jaw fragment exhibit several characteristics typical of juvenile crocodylians. They also display a combination of features not seen in any other taxon, warranting the erection of a new species and genus, Qianshanosuchus youngi gen. & sp. nov. Its affinities are tested in phylogenetic analyses based on two recent character matrices of Eusuchia. To assess the effect of juvenile characteristics on the outcome of the phylogenetic analyses, juvenile specimens of extant crocodylian taxa are analysed in the same way, showing that the effect of their ontogenetic stage on their placement in the tree is minimal. Our analyses point to a basal crocodyloid position for Q. youngi. With these findings, the presence of Crocodyloidea in Asia is extended to the early Palaeocene, 15–20 Myr earlier than formerly thought. Furthermore, our results corroborate previous hypotheses of a Palaeocene dispersal route of Asiatosuchus-like crocodyloids from Asia into Europe.
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Affiliation(s)
- Sophie A Boerman
- Department of Earth and Environmental Sciences, KU Leuven , 3001 Leuven , Belgium
- Directorate Earth and History of Life, Royal Belgian Institute of Natural Sciences , 29 Rue Vautier, B-1000 Brussels , Belgium
| | - Gwendal Perrichon
- Laboratoire de Géologie de Lyon: Terre, Planètes, et Environnement, UMR 5276, CNRS, ENS de Lyon, Université Claude Bernard Lyon 1, Université de Lyon , 46 Allée d’Italie, F-69342 Lyon , France
| | - Jian Yang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences , Xiangshan, Beijing 100093 , China
| | - Cheng-Sen Li
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences , Xiangshan, Beijing 100093 , China
| | - Jeremy E Martin
- Laboratoire de Géologie de Lyon: Terre, Planètes, et Environnement, UMR 5276, CNRS, ENS de Lyon, Université Claude Bernard Lyon 1, Université de Lyon , 46 Allée d’Italie, F-69342 Lyon , France
| | - Robert P Speijer
- Department of Earth and Environmental Sciences, KU Leuven , 3001 Leuven , Belgium
| | - Thierry Smith
- Directorate Earth and History of Life, Royal Belgian Institute of Natural Sciences , 29 Rue Vautier, B-1000 Brussels , Belgium
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4
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Salas-Gismondi R, Ochoa D, Jouve S, Romero PE, Cardich J, Perez A, DeVries T, Baby P, Urbina M, Carré M. Miocene fossils from the southeastern Pacific shed light on the last radiation of marine crocodylians. Proc Biol Sci 2022; 289:20220380. [PMID: 35538785 PMCID: PMC9091840 DOI: 10.1098/rspb.2022.0380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The evolution of crocodylians as sea dwellers remains obscure because living representatives are basically freshwater inhabitants and fossil evidence lacks crucial aspects about crocodylian occupation of marine ecosystems. New fossils from marine deposits of Peru reveal that crocodylians were habitual coastal residents of the southeastern Pacific (SEP) for approximately 14 million years within the Miocene (ca 19 to 5 Ma), an epoch including the highest global peak of marine crocodylian diversity. The assemblage of the SEP comprised two long and slender-snouted (longirostrine) taxa of the Gavialidae: the giant Piscogavialis and a new early diverging species, Sacacosuchus cordovai. Although living gavialids (Gavialis and Tomistoma) are freshwater forms, this remarkable fossil record and a suite of evolutionary morphological analyses reveal that the whole evolution of marine crocodylians pertained to the gavialids and their stem relatives (Gavialoidea). This adaptive radiation produced two longirostrine ecomorphs with dissimilar trophic roles in seawaters and involved multiple transmarine dispersals to South America and most landmasses. Marine gavialoids were shallow sea dwellers, and their Cenozoic diversification was influenced by the availability of coastal habitats. Soon after the richness peak of the Miocene, gavialoid crocodylians disappeared from the sea, probably as part of the marine megafauna extinction of the Pliocene.
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Affiliation(s)
- Rodolfo Salas-Gismondi
- Facultad de Ciencias y Filosofía/Centro de Investigación para el Desarrollo Integral y Sostenible, Laboratorios de Investigación y Desarrollo, Universidad Peruana Cayetano Heredia, Lima, Perú.,Departamento de Paleontología de Vertebrados, Museo de Historia Natural, UNMSM, Lima, Perú.,Division of Paleontology, American Museum of Natural History, New York, NY 10024-5192, USA
| | - Diana Ochoa
- Facultad de Ciencias y Filosofía/Centro de Investigación para el Desarrollo Integral y Sostenible, Laboratorios de Investigación y Desarrollo, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Stephane Jouve
- Centre de Recherche en Paléontologie-Paris (CR2P), Sorbonne Université, CNRS-MNHN-Sorbonne Université, 4 Place Jussieu, 75005 Paris, France
| | - Pedro E Romero
- Facultad de Ciencias y Filosofía/Centro de Investigación para el Desarrollo Integral y Sostenible, Laboratorios de Investigación y Desarrollo, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Jorge Cardich
- Facultad de Ciencias y Filosofía/Centro de Investigación para el Desarrollo Integral y Sostenible, Laboratorios de Investigación y Desarrollo, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Alexander Perez
- Facultad de Ciencias y Filosofía/Centro de Investigación para el Desarrollo Integral y Sostenible, Laboratorios de Investigación y Desarrollo, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Thomas DeVries
- Burke Museum of Natural History and Culture, University of Washington, Seattle, WA 98195, USA
| | - Patrice Baby
- Géosciences- Environnements Toulouse, Université de Toulouse; UPS (SVT-OMP), CNRS, IRD, 14 Avenue Édouard Belin, F-31400 Toulouse, France
| | - Mario Urbina
- Departamento de Paleontología de Vertebrados, Museo de Historia Natural, UNMSM, Lima, Perú
| | - Matthieu Carré
- Facultad de Ciencias y Filosofía/Centro de Investigación para el Desarrollo Integral y Sostenible, Laboratorios de Investigación y Desarrollo, Universidad Peruana Cayetano Heredia, Lima, Perú.,LOCEAN Laboratory, UMR7159 (CNRS-IRD-MNHN-Sorbonnne Universités), Paris, France
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5
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Iijima M, Qiao Y, Lin W, Peng Y, Yoneda M, Liu J. An intermediate crocodylian linking two extant gharials from the Bronze Age of China and its human-induced extinction. Proc Biol Sci 2022; 289:20220085. [PMID: 35259993 PMCID: PMC8905159 DOI: 10.1098/rspb.2022.0085] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
A solid phylogenetic framework is the basis of biological studies, yet higher level relationships are still unresolved in some major vertebrate lineages. One such group is Crocodylia, where the branching pattern of three major families (Alligatoridae, Crocodylidae and Gavialidae) has been disputed over decades due to the uncertain relationship of two slender-snouted lineages, gavialines and tomistomines. Here, we report a bizarre crocodylian from the Bronze Age of China, which shows a mosaic of gavialine and tomistomine features across the skeleton, rendering support to their sister taxon relationship as molecular works have consistently postulated. Gavialine characters of the new Chinese crocodylian include a novel configuration of the pterygoid bulla, a vocal structure known in mature male Indian gharials. Extinct gavialines have repeatedly evolved potentially male-only acoustic apparatus of various shapes, illuminating the deep history of sexual selection on acoustic signalling in a slender-snouted group of crocodylians. Lastly, a cutmark analysis combined with accelerator mass spectrometry (AMS) radiocarbon dating of bone remains demonstrated that two individuals from Shang and Zhou dynasties in Guangdong, China, suffered head injuries and decapitation. Archaeological evidence together with historical accounts suggests the human-induced extinction of this unique crocodylian only a few hundred years ago.
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Affiliation(s)
- Masaya Iijima
- School of Resource and Environmental Engineering, Hefei University of Technology, 193 Tunxi Road, Baohe, Hefei, Anhui 230009, People's Republic of China,Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA,Nagoya University Museum, Furocho, Chikusa-Ku, Nagoya, Aichi 464-8601, Japan
| | - Yu Qiao
- School of Resource and Environmental Engineering, Hefei University of Technology, 193 Tunxi Road, Baohe, Hefei, Anhui 230009, People's Republic of China
| | - Wenbin Lin
- Xinhui Museum, 12 Gongyuan Road, Xinhui, Jiangmen, Guangdong 529199, People's Republic of China
| | - Youjie Peng
- Shunde Museum, Bishui Road, Shunde, Foshan, Guangdong 528300, People's Republic of China
| | - Minoru Yoneda
- The University Museum, The University of Tokyo, Hongo 7-3-1, Bunkyo, Tokyo 113-0033, Japan
| | - Jun Liu
- School of Resource and Environmental Engineering, Hefei University of Technology, 193 Tunxi Road, Baohe, Hefei, Anhui 230009, People's Republic of China
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6
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Darlim G, Lee MSY, Walter J, Rabi M. The impact of molecular data on the phylogenetic position of the putative oldest crown crocodilian and the age of the clade. Biol Lett 2022; 18:20210603. [PMID: 35135314 PMCID: PMC8825999 DOI: 10.1098/rsbl.2021.0603] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The use of molecular data for living groups is vital for interpreting fossils, especially when morphology-only analyses retrieve problematic phylogenies for living forms. These topological discrepancies impact on the inferred phylogenetic position of many fossil taxa. In Crocodylia, morphology-based phylogenetic inferences differ fundamentally in placing Gavialis basal to all other living forms, whereas molecular data consistently unite it with crocodylids. The Cenomanian Portugalosuchus azenhae was recently described as the oldest crown crocodilian, with affinities to Gavialis, based on morphology-only analyses, thus representing a potentially important new molecular clock calibration. Here, we performed analyses incorporating DNA data into these morphological datasets, using scaffold and supermatrix (total evidence) approaches, in order to evaluate the position of basal crocodylians, including Portugalosuchus. Our analyses incorporating DNA data robustly recovered Portugalosuchus outside Crocodylia (as well as thoracosaurs, planocraniids and Borealosuchus spp.), questioning the status of Portugalosuchus as crown crocodilian and any future use as a node calibration in molecular clock studies. Finally, we discuss the impact of ambiguous fossil calibration and how, with the increasing size of phylogenomic datasets, the molecular scaffold might be an efficient (though imperfect) approximation of more rigorous but demanding supermatrix analyses.
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Affiliation(s)
- Gustavo Darlim
- Department of Geosciences, Eberhard Karls Universität Tübingen, Hölderlinstraße 12, 72074 Tübingen, Germany
| | - Michael S. Y. Lee
- School of Biological Sciences, Flinders University, GPO Box 2100, South Australia 5001, Australia,Australia Earth Sciences Section, South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia
| | - Jules Walter
- Department of Geosciences, Eberhard Karls Universität Tübingen, Hölderlinstraße 12, 72074 Tübingen, Germany,Dipartimento di Scienze della Terra, Universitàt degli Studi di Torino, Via Valperga Caluso 35, 10125 Torino, Italy
| | - Márton Rabi
- Department of Geosciences, Eberhard Karls Universität Tübingen, Hölderlinstraße 12, 72074 Tübingen, Germany,Central Natural Science Collections, Martin-Luther University Halle-Wittenberg, D-06108 Halle (Saale), Germany
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7
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Kuzmin IT, Boitsova EA, Gombolevskiy VA, Mazur EV, Morozov SP, Sennikov AG, Skutschas PP, Sues H. Braincase anatomy of extant Crocodylia, with new insights into the development and evolution of the neurocranium in crocodylomorphs. J Anat 2021; 239:983-1038. [PMID: 34176132 PMCID: PMC8546529 DOI: 10.1111/joa.13490] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/02/2021] [Accepted: 06/03/2021] [Indexed: 12/30/2022] Open
Abstract
Present-day crocodylians exhibit a remarkably akinetic skull with a highly modified braincase. We present a comprehensive description of the neurocranial osteology of extant crocodylians, with notes on the development of individual skeletal elements and a discussion of the terminology used for this project. The quadrate is rigidly fixed by multiple contacts with most braincase elements. The parabasisphenoid is sutured to the pterygoids (palate) and the quadrate (suspensorium); as a result, the basipterygoid joint is completely immobilized. The prootic is reduced and externally concealed by the quadrate. It has a verticalized buttress that participates in the canal for the temporal vasculature. The ventrolateral processes of the otoccipitals completely cover the posteroventral region of the braincase, enclose the occipital nerves and blood vessels in narrow bony canals and also provide additional sutural contacts between the braincase elements and further consolidate the posterior portion of the crocodylian skull. The otic capsule of crocodylians has a characteristic cochlear prominence that corresponds to the lateral route of the perilymphatic sac. Complex internal structures of the otoccipital (extracapsular buttress) additionally arrange the neurovascular structures of the periotic space of the cranium. Most of the braincase elements of crocodylians are excavated by the paratympanic pneumatic sinuses. The braincase in various extant crocodylians has an overall similar structure with some consistent variation between taxa. Several newly observed features of the braincase are present in Gavialis gangeticus and extant members of Crocodylidae to the exclusion of alligatorids: the reduced exposure of the prootic buttress on the floor of the temporal canal, the sagittal nuchal crest of the supraoccipital projecting posteriorly beyond the postoccipital processes and the reduced paratympanic pneumaticity. The most distinctive features of the crocodylian braincase (fixed quadrate and basipterygoid joint, consolidated occiput) evolved relatively rapidly at the base of Crocodylomorpha and accompanied the initial diversification of this clade during the Late Triassic and Early Jurassic. We hypothesize that profound rearrangements in the individual development of the braincases of basal crocodylomorphs underlie these rapid evolutionary modifications. These rearrangements are likely reflected in the embryonic development of extant crocodylians and include the involvement of neomorphic dermal anlagen in different portions of the developing chondrocranium, the extensive ossification of the palatoquadrate cartilage as a single expanded quadrate and the anteromedial inclination of the quadrate.
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Affiliation(s)
- Ivan T. Kuzmin
- Department of Vertebrate ZoologySaint Petersburg State UniversitySt. PetersburgRussian Federation
| | - Elizaveta A. Boitsova
- Department of Vertebrate ZoologySaint Petersburg State UniversitySt. PetersburgRussian Federation
| | - Victor A. Gombolevskiy
- Research and Practical Clinical Center of Diagnostics and Telemedicine TechnologiesMoscowRussian Federation
| | - Evgeniia V. Mazur
- Department of Vertebrate ZoologySaint Petersburg State UniversitySt. PetersburgRussian Federation
| | - Sergey P. Morozov
- Research and Practical Clinical Center of Diagnostics and Telemedicine TechnologiesMoscowRussian Federation
| | | | - Pavel P. Skutschas
- Department of Vertebrate ZoologySaint Petersburg State UniversitySt. PetersburgRussian Federation
| | - Hans‐Dieter Sues
- Department of PaleobiologyNational Museum of Natural HistorySmithsonian InstitutionWashingtonDCUSA
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8
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Rio JP, Mannion PD. Phylogenetic analysis of a new morphological dataset elucidates the evolutionary history of Crocodylia and resolves the long-standing gharial problem. PeerJ 2021; 9:e12094. [PMID: 34567843 PMCID: PMC8428266 DOI: 10.7717/peerj.12094] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 08/09/2021] [Indexed: 12/16/2022] Open
Abstract
First appearing in the latest Cretaceous, Crocodylia is a clade of semi-aquatic, predatory reptiles, defined by the last common ancestor of extant alligators, caimans, crocodiles, and gharials. Despite large strides in resolving crocodylian interrelationships over the last three decades, several outstanding problems persist in crocodylian systematics. Most notably, there has been persistent discordance between morphological and molecular datasets surrounding the affinities of the extant gharials, Gavialis gangeticus and Tomistoma schlegelii. Whereas molecular data consistently support a sister taxon relationship, in which they are more closely related to crocodylids than to alligatorids, morphological data indicate that Gavialis is the sister taxon to all other extant crocodylians. Here we present a new morphological dataset for Crocodylia based on a critical reappraisal of published crocodylian character data matrices and extensive firsthand observations of a global sample of crocodylians. This comprises the most taxonomically comprehensive crocodylian dataset to date (144 OTUs scored for 330 characters) and includes a new, illustrated character list with modifications to the construction and scoring of characters, and 46 novel characters. Under a maximum parsimony framework, our analyses robustly recover Gavialis as more closely related to Tomistoma than to other extant crocodylians for the first time based on morphology alone. This result is recovered regardless of the weighting strategy and treatment of quantitative characters. However, analyses using continuous characters and extended implied weighting (with high k-values) produced the most resolved, well-supported, and stratigraphically congruent topologies overall. Resolution of the gharial problem reveals that: (1) several gavialoids lack plesiomorphic features that formerly drew them towards the stem of Crocodylia; and (2) more widespread similarities occur between species traditionally divided into tomistomines and gavialoids, with these interpreted here as homology rather than homoplasy. There remains significant temporal incongruence regarding the inferred divergence timing of the extant gharials, indicating that several putative gavialids ('thoracosaurs') are incorrectly placed and require future re-appraisal. New alligatoroid interrelationships include: (1) support for a North American origin of Caimaninae in the latest Cretaceous; (2) the recovery of the early Paleogene South American taxon Eocaiman as a 'basal' alligatoroid; and (3) the paraphyly of the Cenozoic European taxon Diplocynodon. Among crocodyloids, notable results include modifications to the taxonomic content of Mekosuchinae, including biogeographic affinities of this clade with latest Cretaceous-early Paleogene Asian crocodyloids. In light of our new results, we provide a comprehensive review of the evolutionary and biogeographic history of Crocodylia, which included multiple instances of transoceanic and continental dispersal.
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Affiliation(s)
- Jonathan P. Rio
- Department of Earth Science and Engineering, Imperial College London, London, United Kingdom
| | - Philip D. Mannion
- Department of Earth Sciences, University College London, London, United Kingdom
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9
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Ristevski J, Price GJ, Weisbecker V, Salisbury SW. First record of a tomistomine crocodylian from Australia. Sci Rep 2021; 11:12158. [PMID: 34108569 PMCID: PMC8190066 DOI: 10.1038/s41598-021-91717-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 05/10/2021] [Indexed: 02/05/2023] Open
Abstract
Based on the known fossil record, the majority of crocodylians from the Cenozoic Era of Australia are referred to the extinct clade Mekosuchinae. The only extant crocodylians in Australia are two species of Crocodylus. Hence, the viewpoint that Crocodylus and mekosuchines have been the only crocodylians inhabiting Australia during the Cenozoic has remained largely undisputed. Herein we describe Australia's first tomistomine crocodylian, Gunggamarandu maunala gen. et sp. nov., thus challenging the notion of mekosuchine dominance during most of the Cenozoic. The holotype specimen of Gunggamarandu maunala derives from the Pliocene or Pleistocene of south-eastern Queensland, marking the southern-most global record for Tomistominae. Gunggamarandu maunala is known from a large, incomplete cranium that possesses a unique combination of features that distinguishes it from other crocodylians. Phylogenetic analyses place Gunggamarandu in a basal position within Tomistominae, specifically as a sister taxon to Dollosuchoides from the Eocene of Europe. These results hint at a potential ghost lineage between European and Australian tomistomines going back more than 50 million years. The cranial proportions of the Gunggamarandu maunala holotype specimen indicate it is the largest crocodyliform yet discovered from Australia.
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Affiliation(s)
- Jorgo Ristevski
- School of Biological Sciences, The University of Queensland, Brisbane, QLD, 4072, Australia.
| | - Gilbert J Price
- School of Earth and Environmental Sciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Vera Weisbecker
- School of Biological Sciences, The University of Queensland, Brisbane, QLD, 4072, Australia
- College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia
| | - Steven W Salisbury
- School of Biological Sciences, The University of Queensland, Brisbane, QLD, 4072, Australia
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10
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Hekkala E, Gatesy J, Narechania A, Meredith R, Russello M, Aardema ML, Jensen E, Montanari S, Brochu C, Norell M, Amato G. Paleogenomics illuminates the evolutionary history of the extinct Holocene "horned" crocodile of Madagascar, Voay robustus. Commun Biol 2021; 4:505. [PMID: 33907305 PMCID: PMC8079395 DOI: 10.1038/s42003-021-02017-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 03/24/2021] [Indexed: 12/12/2022] Open
Abstract
Ancient DNA is transforming our ability to reconstruct historical patterns and mechanisms shaping modern diversity and distributions. In particular, molecular data from extinct Holocene island faunas have revealed surprising biogeographic scenarios. Here, we recovered partial mitochondrial (mt) genomes for 1300-1400 year old specimens (n = 2) of the extinct "horned" crocodile, Voay robustus, collected from Holocene deposits in southwestern Madagascar. Phylogenetic analyses of partial mt genomes and tip-dated timetrees based on molecular, fossil, and stratigraphic data favor a sister group relationship between Voay and Crocodylus (true crocodiles). These well supported trees conflict with recent morphological systematic work that has consistently placed Voay within Osteolaeminae (dwarf crocodiles and kin) and provide evidence for likely homoplasy in crocodylian cranial anatomy and snout shape. The close relationship between Voay and Crocodylus lends additional context for understanding the biogeographic origins of these genera and refines competing hypotheses for the recent extinction of Voay from Madagascar.
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Affiliation(s)
- E Hekkala
- Department of Biological Sciences, Fordham University, Bronx, NY, USA.
- American Museum of Natural History, New York, NY, USA.
| | - J Gatesy
- American Museum of Natural History, New York, NY, USA
| | - A Narechania
- American Museum of Natural History, New York, NY, USA
| | - R Meredith
- American Museum of Natural History, New York, NY, USA
- Montclair State University, Montclair, NJ, USA
| | - M Russello
- University of British Columbia, Department of Biology, Kelowna, BC, Canada
| | - M L Aardema
- American Museum of Natural History, New York, NY, USA
- Montclair State University, Montclair, NJ, USA
| | - E Jensen
- University of British Columbia, Department of Biology, Kelowna, BC, Canada
- Newcastle University, School of Natural and Environmental Sciences Ecology Group, Newcastle, UK
| | - S Montanari
- American Museum of Natural History, New York, NY, USA
| | - C Brochu
- University of Iowa, Department of Geosciences, Iowa City, IA, USA
| | - M Norell
- American Museum of Natural History, New York, NY, USA
| | - G Amato
- American Museum of Natural History, New York, NY, USA
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11
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Ristevski J, Yates AM, Price GJ, Molnar RE, Weisbecker V, Salisbury SW. Australia's prehistoric 'swamp king': revision of the Plio-Pleistocene crocodylian genus Pallimnarchus de Vis, 1886. PeerJ 2020; 8:e10466. [PMID: 33391869 PMCID: PMC7759136 DOI: 10.7717/peerj.10466] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 11/10/2020] [Indexed: 12/16/2022] Open
Abstract
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.
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Affiliation(s)
- Jorgo Ristevski
- School of Biological Sciences, The Univeristy of Queensland, Brisbane, QLD, Australia
| | - Adam M. Yates
- Museum of Central Australia, Museum and Art Gallery of the Northern Territory, Alice Springs, NT, Australia
| | - Gilbert J. Price
- School of Earth and Environmental Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Ralph E. Molnar
- University of California Museum of Paleontology, Berkeley, CA, USA
| | - Vera Weisbecker
- School of Biological Sciences, The Univeristy of Queensland, Brisbane, QLD, Australia
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia
| | - Steven W. Salisbury
- School of Biological Sciences, The Univeristy of Queensland, Brisbane, QLD, Australia
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12
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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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13
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Iijima M, Kubo T. Intervertebral joint polarity reversions in extant and extinct crocodylians. ACTA ZOOL-STOCKHOLM 2020. [DOI: 10.1111/azo.12346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Masaya Iijima
- Department of Biological Sciences Clemson University Clemson SC USA
- Nagoya University Museum Nagoya Aichi Japan
- Engineering Research Center for Mineral Resources and Mine Environments, School of Resource and Environmental Engineering Hefei University of Technology Hefei China
| | - Tai Kubo
- The University Museum The University of Tokyo Tokyo Japan
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14
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Hutchinson JR, Felkler D, Houston K, Chang YM, Brueggen J, Kledzik D, Vliet KA. Divergent evolution of terrestrial locomotor abilities in extant Crocodylia. Sci Rep 2019; 9:19302. [PMID: 31848420 PMCID: PMC6917812 DOI: 10.1038/s41598-019-55768-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 12/03/2019] [Indexed: 12/14/2022] Open
Abstract
Extant Crocodylia are exceptional because they employ almost the full range of quadrupedal footfall patterns ("gaits") used by mammals; including asymmetrical gaits such as galloping and bounding. Perhaps this capacity evolved in stem Crocodylomorpha, during the Triassic when taxa were smaller, terrestrial, and long-legged. However, confusion about which Crocodylia use asymmetrical gaits and why persists, impeding reconstructions of locomotor evolution. Our experimental gait analysis of locomotor kinematics across 42 individuals from 15 species of Crocodylia obtained 184 data points for a wide velocity range (0.15-4.35 ms-1). Our results suggest either that asymmetrical gaits are ancestral for Crocodylia and lost in the alligator lineage, or that asymmetrical gaits evolved within Crocodylia at the base of the crocodile line. Regardless, we recorded usage of asymmetrical gaits in 7 species of Crocodyloidea (crocodiles); including novel documentation of these behaviours in 5 species (3 critically endangered). Larger Crocodylia use relatively less extreme gait kinematics consistent with steeply decreasing athletic ability with size. We found differences between asymmetrical and symmetrical gaits in Crocodylia: asymmetrical gaits involved greater size-normalized stride frequencies and smaller duty factors (relative ground contact times), consistent with increased mechanical demands. Remarkably, these gaits did not differ in maximal velocities obtained: whether in Alligatoroidea or Crocodyloidea, trotting or bounding achieved similar velocities, revealing that the alligator lineage is capable of hitherto unappreciated extreme locomotor performance despite a lack of asymmetrical gait usage. Hence asymmetrical gaits have benefits other than velocity capacity that explain their prevalence in Crocodyloidea and absence in Alligatoroidea-and their broader evolution.
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Affiliation(s)
- John R Hutchinson
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hawkshead Lane, North Mymms, AL9 7TA, United Kingdom.
| | - Dean Felkler
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, The Royal Veterinary College, Hawkshead Lane, North Mymms, AL9 7TA, United Kingdom
| | - Kati Houston
- St Augustine Alligator Farm and Zoological Park, St Augustine, Florida, USA
| | - Yu-Mei Chang
- Research Support Office, The Royal Veterinary College, Royal College Street, London, NW1 0TU, United Kingdom
| | - John Brueggen
- St Augustine Alligator Farm and Zoological Park, St Augustine, Florida, USA
| | - David Kledzik
- St Augustine Alligator Farm and Zoological Park, St Augustine, Florida, USA
| | - Kent A Vliet
- St Augustine Alligator Farm and Zoological Park, St Augustine, Florida, USA
- University of Florida, Department of Biology, 208 Carr Hall, PO Box 118525, Gainesville, Florida, 32611-8525, USA
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15
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Groh SS, Upchurch P, Barrett PM, Day JJ. The phylogenetic relationships of neosuchian crocodiles and their implications for the convergent evolution of the longirostrine condition. Zool J Linn Soc 2019. [DOI: 10.1093/zoolinnean/zlz117] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Since their origin in the Late Triassic, crocodylomorphs have had a long history of evolutionary change. Numerous studies examined their phylogeny, but none have attempted to unify their morphological characters into a single, combined dataset. Following a comprehensive review of published character sets, we present a new dataset for the crocodylomorph clade Neosuchia consisting of 569 morphological characters for 112 taxa. For the first time in crocodylian phylogenetic studies, quantitative variation was treated as continuous data (82 characters). To provide the best estimate of neosuchian relationships, and to investigate the origins of longirostry, these data were analysed using a variety of approaches. Our results show that equally weighted parsimony and Bayesian methods cluster unrelated longirostrine forms together, producing a topology that conflicts strongly with their stratigraphic distributions. By contrast, applying extended implied weighting improves stratigraphic congruence and removes longirostrine clustering. The resulting topologies resolve the major neosuchian clades, confirming several recent hypotheses regarding the phylogenetic placements of particular species (e.g. Baryphracta deponiae as a member of Diplocynodontinae) and groups (e.g. Tethysuchia as non-eusuchian neosuchians). The longirostrine condition arose at least three times independently by modification of the maxilla and premaxilla, accompanied by skull roof changes unique to each longirostrine clade.
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Affiliation(s)
- Sebastian S Groh
- Department of Earth Sciences, University College London, London, UK
- Department of Earth Sciences, Natural History Museum, London, UK
| | - Paul Upchurch
- Department of Earth Sciences, University College London, London, UK
| | - Paul M Barrett
- Department of Earth Sciences, Natural History Museum, London, UK
| | - Julia J Day
- Department of Genetics, Environment and Evolution, University College London, London, UK
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16
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Souza RG, Figueiredo RG, Azevedo SAK, Riff D, Kellner AWA. Systematic revision of Sarcosuchus hartti (Crocodyliformes) from the Recôncavo Basin (Early Cretaceous) of Bahia, north-eastern Brazil. Zool J Linn Soc 2019. [DOI: 10.1093/zoolinnean/zlz057] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
AbstractSarcosuchus hartii was a top predator that inhabited the fluvial and coastal areas of north-eastern Brazil during the Early Cretaceous. Several fossil remains were recovered during the late 19th and early 20th centuries from strata that outcrop in the Recôncavo Basin in the state of Bahia. A re-analysis of this material shows that S. hartii is a valid species. The Brazilian taxon differs from the African Sarcosuchus imperator in the unique pattern of anastomosing ornamentation observed on the enamel surface. The inclusion of S. hartii in a novel phylogenetic analysis recovered it inside Tethysuchia, a large clade comprising South and North American pholidosaurids along Elosuchidae and Dyrosauridae. The evolutionary origin of Sarcosuchus is likely related to a cladogenesis event that resulted from the break-up of Gondwana.
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Affiliation(s)
- Rafael G Souza
- Laboratório de Sistemática e Tafonomia de Vertebrados Fósseis, Setor de Paleovertebrados, Departamento de Geologia e Paleontologia, Museu Nacional, Universidade Federal do Rio de Janeiro, Quinta da Boa Vista s/n, São Cristóvão, Rio de Janeiro, RJ, Brazil
| | - Rodrigo G Figueiredo
- Departamento de Biologia, Universidade Federal do Espírito Santo, Alto Universitário s/n, Guararema, Alegre, ES, Brazil
| | - Sérgio A K Azevedo
- Laboratório de Processamento de Imagem Digital, Setor de Paleovertebrados, Departamento de Geologia e Paleontologia, Museu Nacional, Universidade Federal do Rio de Janeiro, Quinta da Boa Vista s/n, São Cristóvão, Rio de Janeiro, RJ, Brazil
| | - Douglas Riff
- Laboratório de Paleontologia, Instituto de Biologia, Universidade Federal de Uberlândia, Rua Ceará s/n, Umuarama, Uberlândia, MG, Brazil
| | - Alexander W A Kellner
- Laboratório de Sistemática e Tafonomia de Vertebrados Fósseis, Setor de Paleovertebrados, Departamento de Geologia e Paleontologia, Museu Nacional, Universidade Federal do Rio de Janeiro, Quinta da Boa Vista s/n, São Cristóvão, Rio de Janeiro, RJ, Brazil
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17
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Sookias RB. Exploring the effects of character construction and choice, outgroups and analytical method on phylogenetic inference from discrete characters in extant crocodilians. Zool J Linn Soc 2019. [DOI: 10.1093/zoolinnean/zlz015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
Phylogenies for fossil taxa must be inferred from morphology, but accuracy of inference is questionable. Here, morphological characters for extant crocodilians are investigated to assess how to improve inference accuracy. The homoplasy of characters is assessed against a DNA-based phylogenetic tree. Cranial characters are significantly less homoplastic, but this result is perhaps confounded by research effort. Meristic characters are significantly more homoplastic and should be used with caution. Characters were reassessed first hand and documented. Those characters passing tests of robust construction are significantly less homoplastic. Suggestions are made for means to improve coding of discrete characters. Phylogenies inferred using only robust characters and a reassessed matrix, including corrected scorings, were not overall closer to the DNA tree, but did often place the gharial (Gavialis) in a position agreeing with or closer to it. The effects of the choice of analytical method were modest, but Bayesian analysis of the reassessed matrix placed Gavialis and Mecistops (slender-snouted crocodile) in DNA-concordant positions. Use of extant rather than extinct outgroups, even with the original matrix, placed Gavialis in a more DNA-concordant position, as did factoring out 3D skull shape. The morphological case for placement of Gavialis outside other extant crocodilians is arguably overstated, with many characters linked to skull shape.
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Affiliation(s)
- Roland B Sookias
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstraße, Berlin, Germany
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