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Narváez I, de Celis A, Escaso F, Martín de Jesús S, Pérez-García A, Ortega F. A new Crocodyloidea from the middle Eocene of Zamora (Duero Basin, Spain). Anat Rec (Hoboken) 2024. [PMID: 38444286 DOI: 10.1002/ar.25422] [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: 12/23/2023] [Revised: 02/07/2024] [Accepted: 02/21/2024] [Indexed: 03/07/2024]
Abstract
The eusuchian crocodyliforms recorded in the Eocene levels of the Spanish Duero Basin belong to three lineages: Planocraniidae, with the species Duerosuchus piscator; Alligatoroidea, represented by several specimens of the genus Diplocynodon; and Crocodyloidea, which includes several specimens traditionally attributed to Asiatosuchus. The genus Asiatosuchus, established in 1940 based on a middle Eocene species from Mongolia, has subsequently served as a wastebasket taxon for Paleogene remains belonging to several species, not only from Asia but also belonging to the European and North American records. Many of these species are known by highly fragmentary remains, sharing the presence of characters such as a flat and triangular skull, and long symphyses in the lower jaw, recognized as characteristic for the crocodyloids. In addition to isolated cranial remains, among the material traditionally attributed to Asiatosuchus at the Duero Basin stands out a nearly complete skull and a left mandible, from the middle Eocene area of Casaseca de Campeán (Zamora Province). The present study analyses in detail these specimens, previously reported during the 1980s, but analyzed in a very preliminary way. They are included for the first time in a phylogenetic analysis to establish the systematic position of this Spanish form. The results confirm that it corresponds to a new species of basal crocodyloid, defined here as Asiatosuchus oenotriensis sp. nov.
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Affiliation(s)
- Iván Narváez
- Grupo de Biología Evolutiva, Departamento de Física Matemática y de Fluidos, Facultad de Ciencias, UNED, Madrid, Spain
| | - Ane de Celis
- Grupo de Biología Evolutiva, Departamento de Física Matemática y de Fluidos, Facultad de Ciencias, UNED, Madrid, Spain
| | - Fernando Escaso
- Grupo de Biología Evolutiva, Departamento de Física Matemática y de Fluidos, Facultad de Ciencias, UNED, Madrid, Spain
| | - Santiago Martín de Jesús
- Colección de Vertebrados Fósiles de la Cuenca del Duero (Sala de las Tortugas), Departamento de Geología, Facultad de Ciencias, Universidad de Salamanca, Salamanca, Spain
| | - Adán Pérez-García
- Grupo de Biología Evolutiva, Departamento de Física Matemática y de Fluidos, Facultad de Ciencias, UNED, Madrid, Spain
| | - Francisco Ortega
- Grupo de Biología Evolutiva, Departamento de Física Matemática y de Fluidos, Facultad de Ciencias, UNED, Madrid, Spain
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2
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Darlim G, Suraprasit K, Chaimanee Y, Tian P, Yamee C, Rugbumrung M, Kaweera A, Rabi M. An extinct deep-snouted Alligator species from the Quaternary of Thailand and comments on the evolution of crushing dentition in alligatorids. Sci Rep 2023; 13:10406. [PMID: 37443318 PMCID: PMC10344928 DOI: 10.1038/s41598-023-36559-6] [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: 04/12/2023] [Accepted: 06/06/2023] [Indexed: 07/15/2023] Open
Abstract
Fossil Alligator remains from Asia are critical for tracing the enigmatic evolutionary origin of the Chinese alligator, Alligator sinensis, the only living representative of Alligatoridae outside the New World. The Asian fossil record is extremely scarce and it remains unknown whether A. sinensis is an anagenetic lineage or alternatively, extinct divergent species were once present. We provide a detailed comparative description of a morphologically highly distinct Alligator skull from the Quaternary of Thailand. Several autapomorphic characters warrant the designation of a new species. Alligator munensis sp. nov. shares obvious derived features with A. sinensis but autapomorphies imply a cladogenetic split, possibly driven by the uplift of the southeastern Tibetan plateau. The presence of enlarged posterior alveoli in Alligator munensis is most consistent with a reversal to the alligatorine ancestral condition of having crushing dentition, a morphology strikingly absent among living alligatorids. Crushing dentition has been previously considered to indicate an ecological specialisation in early alligatorines that was subsequently lost in Alligator spp. However, we argue that there is yet no evidence for crushing dentition reflecting an adaptation for a narrower niche, while opportunistic feeding, including seasonal utilisation of hard-shelled preys, is a reasonable alternative interpretation of its function.
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Affiliation(s)
- Gustavo Darlim
- Department of Geosciences, Eberhard Karls Universität Tübingen, Hölderlinstraße 12, 72074, Tübingen, Germany.
| | - Kantapon Suraprasit
- Department of Geology, Faculty of Science, Center of Excellence in Morphology of Earth Surface and Advanced Geohazards in Southeast Asia (MESA CE), Chulalongkorn University, Bangkok, 10330, Thailand
| | - Yaowalak Chaimanee
- Laboratory PALEVOPRIM, UMR 7262 CNRS, University of Poitiers, 6 Rue Michel Brunet, 86073, Poitiers Cedex 9, France
| | - Pannipa Tian
- Department of Mineral Resources, Rama VI Road, Bangkok, 10400, Thailand
| | - Chotima Yamee
- Department of Mineral Resources, Rama VI Road, Bangkok, 10400, Thailand
| | - Mana Rugbumrung
- Department of Mineral Resources, Rama VI Road, Bangkok, 10400, Thailand
| | - Adulwit Kaweera
- Department of Mineral Resources, Rama VI Road, Bangkok, 10400, Thailand
| | - Márton Rabi
- Department of Geosciences, Eberhard Karls Universität Tübingen, Hölderlinstraße 12, 72074, Tübingen, Germany.
- Central Natural Science Collections, Martin-Luther University Halle-Wittenberg, 06108, Halle (Saale), Germany.
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3
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Massonne T, Böhme M. Re-evaluation of the morphology and phylogeny of Diplocynodon levantinicum Huene & Nikoloff, 1963 and the stratigraphic age of the West Maritsa coal field (Upper Thrace Basin, Bulgaria). PeerJ 2022; 10:e14167. [PMID: 36389401 PMCID: PMC9653056 DOI: 10.7717/peerj.14167] [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: 07/21/2022] [Accepted: 09/12/2022] [Indexed: 11/11/2022] Open
Abstract
Diplocynodon levantinicum Huene & Nikoloff, 1963 was described based on few bone fragments from the West-Maritsa lignite basin of Central Bulgaria. Huene & Nikoloff, 1963 assumed a late Pliocene age, implying that this species represents the stratigraphically youngest crocodilian of Europe. In this current study, we re-evaluate the stratigraphy of the West-Maritsa Basin and conclude a late Oligocene age of ~26 Ma for the Kipra coal-seam, the fossiliferous horizon. Furthermore, topotypical and undescribed D. levantinicum specimens are accessible now and allowed for a deeper taxonomic and phylogenetic analysis. A comparison with other Diplocynodon species reveals D. levantinicum as a valid species, having (1) a long suborbital fenestra, (2) a very short dentary symphysis, (3) a large gap between the first and second dentary alveolus, (4) an occlusion pit in line with the tooth row posterior to the 14th dentary alveolus, (5) a sulcus lateral to the glenoid fossa and, (6) a lingual foramen for the articular artery situated entirely on the surangular. The phylogenetic analyses find D. levantinicum deeply nested inside the Diplocynodontinae subfamily. After the disappearance of the Paratethyan influence (Solenovian regional stage) in the Upper Thrace Basin this species has roamed during the late Oligocene extensive freshwater lake and swamp ecosystems represented by the Maritsa Formation. Diplocynodon levantinicum represents the only nominal Diplocynodon taxon of late Oligocene (Chattian) age.
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Affiliation(s)
- Tobias Massonne
- Senckenberg Center of Human Evolution and Palaeoecology, Tübingen, Germany,Department of Geosciences, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
| | - Madelaine Böhme
- Senckenberg Center of Human Evolution and Palaeoecology, Tübingen, Germany,Department of Geosciences, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
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4
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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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5
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Brochu CA, de Celis A, Adams AJ, Drumheller SK, Nestler JH, Benefit BR, Grossman A, Kirera F, Lehmann T, Liutkus-Pierce C, Manthi FK, McCrossin ML, McNulty KP, Nyaboke Juma R. Giant dwarf crocodiles from the Miocene of Kenya and crocodylid faunal dynamics in the late Cenozoic of East Africa. Anat Rec (Hoboken) 2022; 305:2729-2765. [PMID: 35674271 PMCID: PMC9541231 DOI: 10.1002/ar.25005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 05/13/2022] [Accepted: 05/16/2022] [Indexed: 12/03/2022]
Abstract
We describe two new osteolaemine crocodylids from the Early and early Middle Miocene of Kenya: Kinyang mabokoensis tax. nov. (Maboko, 15 Ma) and Kinyang tchernovi tax. nov. (Karungu and Loperot, 18 Ma). Additional material referable to Kinyang is known from Chianda and Moruorot. The skull was broad and dorsoventrally deep, and the genus can be diagnosed based on the combined presence of a partial overbite, a subdivided fossa for the lateral collateral ligament on the surangular, and a maxilla with no more than 13 alveoli. Phylogenetic analyses based on morphological and combined morphological and molecular data support a referral of Kinyang to Osteolaeminae, and morphological data alone put the new taxon at the base of Euthecodontini. Some Kinyang maxillae preserve blind pits on the medial caviconchal recess wall. Kinyang co‐occurs with the osteolaemine Brochuchus at some localities, and together, they reinforce the phylogenetic disparity between early Neogene osteolaemine‐dominated faunas and faunas dominated by crocodylines beginning in the Late Miocene in the Kenya Rift. The causes of this turnover remain unclear, though changes in prevailing vegetation resulting from tectonic and climatic drivers may provide a partial explanation.
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Affiliation(s)
- Christopher A Brochu
- Department of Earth and Environmental Sciences, University of Iowa, Iowa City, Iowa, USA
| | - Ane de Celis
- Grupo de Biología Evolutiva, Facultad de Ciencias, Universidad Nacional de Educación a Distancia, Madrid, Spain
| | - Amanda J Adams
- Department of Earth and Environmental Sciences, University of Iowa, Iowa City, Iowa, USA.,Department of Biological Sciences, Fort Hays State University, Hays, Kansas, USA
| | - Stephanie K Drumheller
- Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, Tennessee, USA
| | - Jennifer H Nestler
- Department of Earth and Environmental Sciences, University of Iowa, Iowa City, Iowa, USA
| | - Brenda R Benefit
- Department of Anthropology, New Mexico State University, Las Cruces, New Mexico, USA
| | - Aryeh Grossman
- Department of Anatomy, College of Graduate Studies, Midwestern University, Glendale, Arizona, USA.,Arizona College of Veterinary Medicine, Midwestern University, Glendale, Arizona, USA.,Arizona College of Osteopathic Medicine, Midwestern University, Glendale, Arizona, USA
| | - Francis Kirera
- Mercer University School of Medicine, Macon, Georgia, USA
| | - Thomas Lehmann
- Senckenberg Research Institute and Natural History Museum Frankfurt, Frankfurt am Main, Germany
| | - Cynthia Liutkus-Pierce
- Department of Geological and Environmental Sciences, Appalachian State University, Boone, North Carolina, USA
| | - Fredrick K Manthi
- Department of Earth Sciences, National Museums of Kenya, Nairobi, Kenya
| | - Monte L McCrossin
- Department of Anthropology, New Mexico State University, Las Cruces, New Mexico, USA
| | - Kieran P McNulty
- Department of Anthropology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Rose Nyaboke Juma
- Department of Earth Sciences, National Museums of Kenya, Nairobi, Kenya
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6
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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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7
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Stocker MR, Brochu CA, Kirk EC. A new caimanine alligatorid from the Middle Eocene of Southwest Texas and implications for spatial and temporal shifts in Paleogene crocodyliform diversity. PeerJ 2021; 9:e10665. [PMID: 33520458 PMCID: PMC7812925 DOI: 10.7717/peerj.10665] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 12/08/2020] [Indexed: 11/24/2022] Open
Abstract
Dramatic early Cenozoic climatic shifts resulted in faunal reorganization on a global scale. Among vertebrates, multiple groups of mammals (e.g., adapiform and omomyiform primates, mesonychids, taeniodonts, dichobunid artiodactyls) are well known from the Western Interior of North America in the warm, greenhouse conditions of the early Eocene, but a dramatic drop in the diversity of these groups, along with the introduction of more dry-tolerant taxa, occurred near the Eocene–Oligocene boundary. Crocodyliforms underwent a striking loss of diversity at this time as well. Pre-Uintan crocodyliform assemblages in the central Western Interior are characterized by multiple taxa, whereas Chadronian assemblages are depauperate with only Alligator prenasalis previously known. Crocodyliform diversity through the intervening Uintan and Duchesnean is not well understood. The middle Eocene Devil’s Graveyard Formation (DGF) of southwest Texas provides new data from southern latitudes during that crucial period. A new specimen from the middle member of the DGF (late Uintan–Duchesnean) is the most complete cranial material of an alligatorid known from Paleogene deposits outside the Western Interior. We identify this specimen as a caimanine based on notched descending laminae of the pterygoids posterior to the choanae and long descending processes of the exoccipitals that are in contact with the basioccipital tubera. Unlike Eocaiman cavernensis, the anterior palatine process is rounded rather than quadrangular. The relationships and age of this new taxon support the hypothesis that the modern distribution of caimanines represents a contraction of a more expansive early Cenozoic distribution. We hypothesize that the range of caimanines tracked shifting warm, humid climatic conditions that contracted latitudinally toward the hothouse-icehouse transition later in the Eocene.
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Affiliation(s)
- Michelle R Stocker
- Department of Geosciences, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, USA.,Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, USA
| | - Christopher A Brochu
- Department of Earth and Environmental Sciences, University of Iowa, Iowa City, IA, USA
| | - E Christopher Kirk
- Department of Anthropology, The University of Texas at Austin, Austin, TX, USA.,Jackson School Museum of Earth History, The University of Texas at Austin, Austin, TX, USA
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8
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Brochu CA. Pliocene crocodiles from Kanapoi, Turkana Basin, Kenya. J Hum Evol 2020; 140:102410. [DOI: 10.1016/j.jhevol.2017.10.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 08/07/2017] [Accepted: 10/05/2017] [Indexed: 11/25/2022]
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9
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Massonne T, Vasilyan D, Rabi M, Böhme M. A new alligatoroid from the Eocene of Vietnam highlights an extinct Asian clade independent from extant Alligator sinensis. PeerJ 2019; 7:e7562. [PMID: 31720094 PMCID: PMC6839522 DOI: 10.7717/peerj.7562] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 07/27/2019] [Indexed: 11/20/2022] Open
Abstract
During systematic paleontological surveys in the Na Duong Basin in North Vietnam between 2009 and 2012, well-preserved fossilized cranial and postcranial remains belonging to at least 29 individuals of a middle to late Eocene (late Bartonian to Priabonian age (39–35 Ma)) alligatoroid were collected. Comparative anatomical study of the material warrants the diagnosis of a new taxon, Orientalosuchus naduongensis gen. et sp. nov. The combined presence of an enlarged fifth maxillary tooth, prominent preorbital ridges, a large supraoccipital exposure on the skull table, a palatine-pterygoid suture anterior to the posterior end of the suborbital fenestra, and a pterygoid forming a neck surrounding the choana is unique to this species. Unlike previous phylogenies, our parsimony analysis recovers a monophyletic Late Cretaceous to Paleogene East to Southeastern Asian alligatoroid group, here named Orientalosuchina. The group includes Orientalosuchus naduongensis, Krabisuchus siamogallicus, Eoalligator chunyii, Jiangxisuchus nankangensis and Protoalligator huiningensis, all of them sharing a medial shifted quadrate foramen aerum. The recognition of this clade indicates at least two separate dispersal events from North America to Asia: one during the Late Cretaceous by Orientalosuchina and one by the ancestor of Alligator sinensis during the Paleogene or Neogene, the timing of which is poorly constrained.
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Affiliation(s)
- Tobias Massonne
- Department of Geosciences, Eberhard-Karls-Universität Tübingen, Tübingen, Germany.,Senckenberg Center for Human Evolution and Palaeoecology, Tuebingen, Germany
| | - Davit Vasilyan
- JURASSICA Museum, Porrentruy, Switzerland.,Department of Geosciences, University of Fribourg, Fribourg, Switzerland
| | - Márton Rabi
- Department of Geosciences, Eberhard-Karls-Universität Tübingen, Tübingen, Germany.,Central Natural Science Collections, Martin-Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Madelaine Böhme
- Department of Geosciences, Eberhard-Karls-Universität Tübingen, Tübingen, Germany.,Senckenberg Center for Human Evolution and Palaeoecology, Tuebingen, Germany
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10
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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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11
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De Celis A, Narváez I, Ortega F. Spatiotemporal palaeodiversity patterns of modern crocodiles (Crocodyliformes: Eusuchia). Zool J Linn Soc 2019. [DOI: 10.1093/zoolinnean/zlz038] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Abstract
Eusuchia is a crocodyliform clade with a rich and diverse fossil record dating back to the Mesozoic. There are several recent studies that analyse crocodyliform palaeodiversity over time, but none of them focuses exclusively on eusuchians. Thus, we estimated subsampled eusuchian palaeodiversity species dynamics over time not only at a global scale, but also by continents and main crocodylian lineages (Alligatoroidea, Crocodyloidea and Gavialoidea). These estimates reveal complex spatiotemporal palaeodiversity patterns, in which two maxima can be detected: the first during the Palaeocene and the second, which is also the biggest, in the middle-late Miocene. The Palaeocene shift is related to a North American alligatoroid diversification, whereas the middle–late Miocene maximum is related to a diversification of the three main Crocodylia lineages in Gondwanan land masses, but especially in South America. Additionally, a model-based study using generalized least squares was carried out to analyse the relationships between different abiotic and sampling proxies and eusuchian palaeodiversity. The results show that palaeotemperature is the most important factor amongst the analysed proxies, in accordance with previous studies. However, the results suggest that, along with palaeotemperature, other abiotic and/or biotic factors might also be driving eusuchian palaeodiversity dynamics.
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Affiliation(s)
- Ane De Celis
- Grupo de Biología Evolutiva, Departamento de Física Matemática y de Fluidos, Universidad Nacional de Educación a Distancia, Madrid, Spain
| | - Iván Narváez
- Grupo de Biología Evolutiva, Departamento de Física Matemática y de Fluidos, Universidad Nacional de Educación a Distancia, Madrid, Spain
| | - Francisco Ortega
- Grupo de Biología Evolutiva, Departamento de Física Matemática y de Fluidos, Universidad Nacional de Educación a Distancia, Madrid, Spain
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Rio JP, Mannion PD, Tschopp E, Martin JE, Delfino M. Reappraisal of the morphology and phylogenetic relationships of the alligatoroid crocodylian Diplocynodon hantoniensis from the late Eocene of the United Kingdom. Zool J Linn Soc 2019. [DOI: 10.1093/zoolinnean/zlz034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
AbstractDiplocynodon is a genus of basal alligatoroid comprising nine species, which spanned the late Palaeocene to middle Miocene of Europe. Despite recent revisions of most Diplocynodon species, one of the earliest named and most complete, Diplocynodon hantoniensis, has not been re-described for over 150 years. This species is known from the remains of numerous individuals from the Priabonian (late Eocene) Headon Hill Formation, which crops out at Hordle (Hordwell) Cliff in Hampshire, United Kingdom. Here we re-describe and diagnose Diplocynodon hantoniensis, providing the first detailed description of postcranial anatomy in Diplocynodon, and indeed any basal alligatoroid. Diplocynodon hantoniensis is diagnosed by four autapomorphies, including retention of the ectopterygoid–pterygoid flexure through ontogeny and a unique anterior process of the ectopterygoid adjacent to the posteriormost maxillary alveoli. A critical review of previously referred remains from elsewhere in Europe and the USA restricts Diplocynodon hantoniensis to the late Eocene of the UK. Through comparisons with extant crocodylians, the well-preserved postcranial skeleton enables the interpretation of numerous muscle attachments in the forelimbs and hindlimbs, providing a potentially rich source of character data for future phylogenetic analyses. Based on a comparison of humeral morphology between a large sample of crocodylian species, we outline two new morphological characters in the humerus. We include D. hantoniensis in a phylogenetic analysis, including all putative Diplocynodon species (103 taxa scored for 187 characters). We use four different character-weighting schemes: equal weighting, implied weighting (k value = 8) and extended implied weighting with k-values of 4 and 8. In general, these weighted analyses produce congruent results with the equal-weights analysis, and increase the resolution within Diplocynodon. We recover a monophyletic Diplocynodon in three of the four analyses. However, the fourth analysis, with the strongest downweighting of homoplastic characters and missing data (extended implied weighting with k = 4), recovers the Palaeocene Diplocynodon remensis outside Diplocynodon. Our comprehensive revision of one of the most completely known Diplocynodon species facilitates comparisons in the genus, as well as between other basal alligatoroids, and forms the basis for comparing postcranial anatomy in other fossil crocodylians.
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Affiliation(s)
- Jonathan P Rio
- Department of Earth Science and Engineering, Imperial College London, London, UK
| | - Philip D Mannion
- Department of Earth Sciences, University College London, London, UK
| | - Emanuel Tschopp
- Division of Paleontology, American Museum of Natural History, New York, USA
| | - Jeremy E Martin
- Université Lyon, ENS de Lyon, Université Lyon 1, CNRS, UMR 5276 Laboratoire de Géologie de Lyon: Terre, Planète, Environnement, Lyon, France
| | - Massimo Delfino
- Dipartimento di Scienze della Terra, Università di Torino, Torino, Italy
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Edifici ICTAICP, Carrer de les Columnes s/n, Campus de la UAB, Barcelona, Spain
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