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

Research output: Contribution to journalArticle

Abstract

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.

Details

Authors
  • Peter Sjövall
  • Volker Thiel
  • Wenxia Zheng
  • Shosuke Ito
  • Kazumasa Wakamatsu
  • Rolf Hauff
  • Benjamin P. Kear
  • Sven Sachs
  • Per E. Ahlberg
  • Federica Marone
  • Takeo Kuriyama
  • Ola Gustafsson
  • Per Malmberg
  • Aurélien Thomen
  • Irene Rodríguez-Meizoso
  • Makoto Ojika
Organisations
External organisations
  • University of Göttingen
  • North Carolina State University
  • Fujita Health University
  • Uppsala University
  • Paul Scherrer Institute
  • University of Hyogo
  • Chalmers University of Technology
  • University of Gothenburg
  • Nagoya University
  • North Carolina Museum of Natural Sciences
  • Research Institutes of Sweden (RISE)
  • Urweltmuseum Hauff
  • Natural History Museum, Bielefeld
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Geology
Original languageEnglish
Pages (from-to)359-365
Number of pages7
JournalNature
Volume564
Issue number7736
Publication statusPublished - 2018
Publication categoryResearch
Peer-reviewedYes