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Soft-tissue evidence for homeothermy and crypsis in a Jurassic ichthyosaur

Author:
  • Johan Lindgren
  • Peter Sjövall
  • Volker Thiel
  • Wenxia Zheng
  • Shosuke Ito
  • Kazumasa Wakamatsu
  • Rolf Hauff
  • Benjamin P. Kear
  • Anders Engdahl
  • Carl Alwmark
  • Mats E. Eriksson
  • Martin Jarenmark
  • Sven Sachs
  • Per E. Ahlberg
  • Federica Marone
  • Takeo Kuriyama
  • Ola Gustafsson
  • Per Malmberg
  • Aurélien Thomen
  • Irene Rodríguez-Meizoso
  • Per Uvdal
  • Makoto Ojika
  • Mary H. Schweitzer
Publishing year: 2018
Language: English
Pages: 359-365
Publication/Series: Nature
Volume: 564
Issue: 7736
Document type: Journal article
Publisher: Nature Publishing Group

Abstract english

Ichthyosaurs are extinct marine reptiles that display a notable external similarity to modern toothed whales. Here we show that this resemblance is more than skin deep. We apply a multidisciplinary experimental approach to characterize the cellular and molecular composition of integumental tissues in an exceptionally preserved specimen of the Early Jurassic ichthyosaur Stenopterygius. Our analyses recovered still-flexible remnants of the original scaleless skin, which comprises morphologically distinct epidermal and dermal layers. These are underlain by insulating blubber that would have augmented streamlining, buoyancy and homeothermy. Additionally, we identify endogenous proteinaceous and lipid constituents, together with keratinocytes and branched melanophores that contain eumelanin pigment. Distributional variation of melanophores across the body suggests countershading, possibly enhanced by physiological adjustments of colour to enable photoprotection, concealment and/or thermoregulation. Convergence of ichthyosaurs with extant marine amniotes thus extends to the ultrastructural and molecular levels, reflecting the omnipresent constraints of their shared adaptation to pelagic life.

Keywords

  • Geology

Other

Published
  • Lund Vision Group
  • ISSN: 0028-0836
Mats Eriksson
E-mail: mats [dot] eriksson [at] geol [dot] lu [dot] se

Professor

Lithosphere and Biosphere Science

+46 46 222 96 02

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