Giant dwarf crocodiles from the Miocene of Kenya and crocodylid faunal dynamics in the late Cenozoic of East Africa

Christopher A. Brochu, Ane de Celis, Amanda J. Adams, Stephanie K. Drumheller, Jennifer H. Nestler, Brenda R. Benefit, Aryeh Grossman, Francis Kirera, Thomas Lehmann, Cynthia Liutkus-Pierce, Fredrick K. Manthi, Monte L. McCrossin, Kieran P. McNulty, Rose Nyaboke Juma

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

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.

Original languageEnglish (US)
Pages (from-to)2729-2765
Number of pages37
JournalAnatomical Record
Volume305
Issue number10
DOIs
StatePublished - Oct 2022

Bibliographical note

Funding Information:
Boise Fund, Oxford University; Fulbright Collaborative Research Program; International Union for the Conservation of Nature Crocodile Specialist Group; Karl und Marie Schack‐Stiftung Fund; Leakey Foundation; Ministerio de Universidades de España, Grant/Award Number: FPU 2016/01058; National Geographic Society; National Science Foundation, Grant/Award Numbers: BCS 1231676, BCS 1231749, BCS 1241807, BCS 124812, BCS 9200951, BCS 9505778, DEB 0444133, DEB 1257786; University of Iowa Department of Earth and Environmental Sciences; University of Iowa Graduate and Professional Student Government; University of Iowa Graduate Student Senate; Vereinigung von Freunden und Förderern der Goethe‐Universität Frankfurt; Wenner‐Gren Foundation Funding information

Funding Information:
The authors are grateful to S. Maidment and L. Steel (NHMUK), A. Resetar and J. Mata (FMNH), C. Mehling and D. Kizirian (AMNH), C. Sheehy (UFMNH), A. Wynn (USNM), and E. Loeffler (BRSUG) for access to collections and data that proved critical in completing this project. The authors are deeply indebted to many field collectors, preparators and collections staff at the KNM, including B.O. Onyango, who did much of the preparation of the Maboko material; O. Mwebi, who, along with his staff, facilitated access to the modern osteological collections; and J. KIbii, T. Gichunge, and R Ngechu, who assisted with imaging of the holotype of . Discussions with S. Feakins, J. Head, E. Hekkala, C. Holliday, M. Leakey, J.M. Plavcan, C. Sumrall, M. Shirley, and C. Ward helped them strengthen the manuscript with valuable information and context. The authors acknowledge the computational resources and assistance provided by the Centro de Computación de Alto Rendimiento CCAR‐UNED. This work was supported by the US National Science Foundation (NSF DEB 1257786 and DEB 0444133 to Brochu, BCS 1241807 and BCS 124812 to McNulty, BCS 1231676 to J.M. Plavcan, BCS 1231749 to C. Ward, BCS 9505778 and BCS 9200951 to McCrossin and Benefit); the Leakey Foundation (to Brochu, Drumheller, Grossman, Liutkus‐Pierce, McCrossin, and Benefit); the National Geographic Society, Wenner Gren Foundation for Anthropological Research, Fulbright Collaborative Research Program, and Boise Fund of Oxford University (to McCrossin and Benefit); the IUCN Crocodile Specialist Group (to Nestler); the University of Iowa Department of Earth and Environmental Sciences (to Brochu, Nestler, and Adams); the University of Iowa Graduate Student Senate (Supplemental Travel Grant and T. Anne Cleary International Dissertation Research Fellowship) and Graduate and Professional Student Government (to Adams); the Karl und Marie Schack‐Stiftung Fund and Vereinigung von Freunden und Förderern der Goethe‐Universität Frankfurt (to Lehmann); and the Ministerio de Universidades de España (FPU 2016/01058 to de Celis). K. mabokoensis

Publisher Copyright:
© 2022 The Authors. The Anatomical Record published by Wiley Periodicals LLC on behalf of American Association for Anatomy.

Keywords

  • Africa
  • Crocodylia
  • Crocodylidae
  • Osteolaeminae
  • paleoecology
  • phylogenetics

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