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

Lindgren, Johan LU ; Sjövall, Peter; Thiel, Volker; Zheng, Wenxia; Ito, Shosuke; Wakamatsu, Kazumasa; Hauff, Rolf; Kear, Benjamin P.; Engdahl, Anders LU and Alwmark, Carl LU , et al. (2018) In Nature 564(7736). p.359-365
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... (More)

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.

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Nature
volume
564
issue
7736
pages
7 pages
publisher
Nature Publishing Group
external identifiers
  • scopus:85058887475
ISSN
0028-0836
DOI
10.1038/s41586-018-0775-x
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English
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yes
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ed703cf2-d742-4186-b3f4-6f3ddf2269ab
date added to LUP
2019-01-03 09:56:04
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2019-01-14 16:43:45
@article{ed703cf2-d742-4186-b3f4-6f3ddf2269ab,
  abstract     = {<p>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.</p>},
  author       = {Lindgren, Johan and Sjövall, Peter and Thiel, Volker and Zheng, Wenxia and Ito, Shosuke and Wakamatsu, Kazumasa and Hauff, Rolf and Kear, Benjamin P. and Engdahl, Anders and Alwmark, Carl and Eriksson, Mats E. and Jarenmark, Martin and Sachs, Sven and Ahlberg, Per E. and Marone, Federica and Kuriyama, Takeo and Gustafsson, Ola and Malmberg, Per and Thomen, Aurélien and Rodríguez-Meizoso, Irene and Uvdal, Per and Ojika, Makoto and Schweitzer, Mary H.},
  issn         = {0028-0836},
  language     = {eng},
  number       = {7736},
  pages        = {359--365},
  publisher    = {Nature Publishing Group},
  series       = {Nature},
  title        = {Soft-tissue evidence for homeothermy and crypsis in a Jurassic ichthyosaur},
  url          = {http://dx.doi.org/10.1038/s41586-018-0775-x},
  volume       = {564},
  year         = {2018},
}