eprintid: 10194213 rev_number: 14 eprint_status: archive userid: 699 dir: disk0/10/19/42/13 datestamp: 2024-07-05 12:44:03 lastmod: 2024-12-17 15:12:55 status_changed: 2024-07-05 12:44:03 type: article metadata_visibility: show sword_depositor: 699 creators_name: Burke, Paul MJ creators_name: Nicholl, Cecily SC creators_name: Pittard, Bethany E creators_name: Sallam, Hesham creators_name: Mannion, Philip D title: The anatomy and taxonomy of the North African Early Miocene crocodylian 'Tomistoma' dowsoni and the phylogenetic relationships of gavialoids ispublished: pub keywords: Gavialis, gavialoids, Tomistoma, phylogenetics, systematics, Miocene note: Copyright © 2024 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. abstract: For decades, the interrelationships of the extant crocodylians Gavialis gangeticus and Tomistoma schlegelii have been debated, with only recent morphological phylogenetic analyses recovering the sister-taxon relationship between these two gavialoid species that has long been apparent in topologies based on molecular data. Several extinct species from the Mediterranean region are currently assigned to Tomistoma; however, their phylogenetic placement is labile, and often they do not form a clade with Tomistoma schlegelii. Here, we present a revision of Tomistoma dowsoni from the Early Miocene of Egypt and Libya, based on the type specimen (a partial snout and mandible) and referred material, including a nearly complete skull. These specimens show no notable anatomical differences and diagnostic features include: (1) a heart-shaped naris; (2) a prefrontal and lacrimal that are equidimensional in anteroposterior length; and (3) a prominent posterior process of the supraoccipital with a convex posterior margin. Maximum parsimony analysis, under both equal and extended implied weighting, recovers Tomistoma dowsoni as a phylogenetically nested gavialine, distantly related to Tomistoma schlegelii and other Mediterranean species currently referred to Tomistoma. Instead, Tomistoma dowsoni forms a sister-taxon relationship with Eogavialis andrewsi, from the Late Miocene of Kenya. Given that this clade does not consistently cluster with the type species of Eogavialis, and that Tomistoma dowsoni is diagnostic and clearly not referrable to Tomistoma, we herein erect the genus Sutekhsuchus, with the new combination Sutekhsuchus dowsoni. Our phylogenetic analyses recover the European Miocene gavialoids in a monophyletic group with the North American Thecachampsa, forming a clade of early-diverging gavialines that underwent transoceanic dispersal. We also recover a monophyletic group of thoracosaurs, comprising Eothoracosaurus, Portugalosuchus, and Thoracosaurus, which is expanded to include other Late Cretaceous–Early Paleogene European, North American, and North African species under extended implied weighting. https://zoobank.org/urn:lsid:zoobank.org:pub:2DE71417-8088-4749-8672-72E4A40C0B39 date: 2024 date_type: published publisher: Taylor & Francis official_url: https://doi.org/10.1080/14772019.2024.2384548 oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 2292163 doi: 10.1080/14772019.2024.2384548 lyricists_name: Mannion, Philip lyricists_id: PDMAN77 actors_name: Mannion, Philip actors_id: PDMAN77 actors_role: owner funding_acknowledgements: RGF\EA\201037, UF160216, URF\R\221010 [Royal Society]; RPG-2021-202 [Leverhulme Trust]; NE/X014010/1 [Natural Environment Research Council [2006-2012]] full_text_status: public publication: Journal of Systematic Palaeontology volume: 22 number: 1 article_number: 2384548 issn: 0968-0462 citation: Burke, Paul MJ; Nicholl, Cecily SC; Pittard, Bethany E; Sallam, Hesham; Mannion, Philip D; (2024) The anatomy and taxonomy of the North African Early Miocene crocodylian 'Tomistoma' dowsoni and the phylogenetic relationships of gavialoids. Journal of Systematic Palaeontology , 22 (1) , Article 2384548. 10.1080/14772019.2024.2384548 <https://doi.org/10.1080/14772019.2024.2384548>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10194213/7/Burke_The%20anatomy%20and%20taxonomy%20of%20the%20North%20African%20Early%20Miocene%20crocodylian%20%20Tomistoma%20%20dowsoni%20and%20the%20phylogenetic%20relationships%20of%20gavialoids.pdf