Swiss Journal of Geosciences

, Volume 103, Issue 2, pp 173–185

Internal vascularity of the dermal plates of Stegosaurus (Ornithischia, Thyreophora)

  • James O. Farlow
  • Shoji Hayashi
  • Glenn J. Tattersall
Article

Abstract

X-ray computed tomography and petrographic thin sectioning were used to study internal features of the plates of the thyreophoran dinosaur Stegosaurus and the osteoderms of Alligator. Infrared thermographic imaging of basking caimans was used to examine possible differential blood flow to osteoderms and other parts of the skin. Multiple large openings in the Stegosaurus plate base lead to a linear, mesiodistally oriented vestibule, which in turn apically sends off multiply branching “pipes”. The pipes are best developed in the basal half of the plate, and communicate with cancellous regions (some of which presumably were vascular spaces) throughout the plate interior. Some internal vascular features also connect with vascular pits and grooves on the plate surface. Alligator osteoderms show a similar internal vascularity. In crocodylians, the osteoderms serve as armor and help to stiffen the back for terrestrial locomotion, but their vascularity enables them to be used as sources of calcium for egg shelling, as sites of lactate sequestration, and possibly for heat exchange with the external environment, as suggested by our infrared thermographic imaging of basking caimans. Thyreophoran osteoderms presumably had multiple functions as well. In Stegosaurus the potential thermoregulatory role of the plates may have been greater than in other thyreophorans, by virtue of their extensive external and internal vascularity, their large size, thin cross-sections above the plate base, dorsal position, and alternating arrangement.

Keywords

Stegosaurus Crocodylians Osteoderms Reptilian thermoregulation X-ray computed tomography Infrared thermographic imaging 

Institutional abbreviations

DMNH

Denver Museum of Nature and Science, Denver, Colorado, USA

HMNS

Hayashibara Museum of Natural Sciences, Okayama, Japan

NSM-PV

National Science Museum, Tokyo, Japan

USNM

National Museum of Natural History, Smithsonian Institution, Washington, DC, USA

YPM

Peabody Museum of Natural History, Yale University, New Haven, Connecticut, USA

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Copyright information

© Swiss Geological Society 2010

Authors and Affiliations

  • James O. Farlow
    • 1
  • Shoji Hayashi
    • 2
  • Glenn J. Tattersall
    • 3
  1. 1.Department of GeosciencesIndiana-Purdue UniversityFort WayneUSA
  2. 2.Department of Earth and Planetary Sciences, Graduate School of ScienceHokkaido UniversitySapporoJapan
  3. 3.Department of Biological SciencesBrock UniversitySt. CatharinesCanada

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