Exceptional stegosaur integument impressions from the Upper Jurassic Morrison Formation of Wyoming

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Abstract

Dinosaur skin impressions are rare in the Upper Jurassic Morrison Formation, but different sites on the Howe Ranch in Wyoming (USA), comprising specimens from diplodocid, camarasaurid, allosaurid and stegosaurian dinosaurs, have proven to be a treasure-trove for these soft-tissue remains. Here we describe stegosaurian skin impressions from North America for the first time, as well as the first case of preservation of an impression of the integument that covered the dorsal plates of stegosaurian dinosaurs in life. Both have been found closely associated with bones of a specimen of the stegosaurian Hesperosaurus mjosi Carpenter, Miles and Cloward 2001. The scales of the skin impression of H. mjosi are very similar in shape and arrangement to those of Gigantspinosaurus sichuanensis Ouyang 1992, the only other stegosaurian dinosaur from which skin impressions have been described. Both taxa show a ground pattern of small polygonal scales, which in some places is interrupted by larger oval tubercles surrounded by the small scales, resulting in rosette-like structures. The respective phylogenetic positions of G. sichuanensis as a basal stegosaurian and H. mjosi as a derived form suggest that most stegosaurians had very similar skin structures, which also match the most common textures known in dinosaurs. The integumentary impression from the dorsal plate brings new data to the long-lasting debate concerning the function of dorsal plates in stegosaurian dinosaurs. Unlike usual dinosaur skin impressions, the integument covering the dorsal plates does not show any scale-like texture. It is smooth with long and parallel, shallow grooves, a structure that is interpreted as representing a keratinous covering of the plates. The presence of such a keratinous covering has affects on all the existing theories concerning the function of stegosaurian plates, including defense, thermoregulation, and display, but does not permit to rule out any of them.

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Abbreviations

BRSM:

Bristol’s City Museum and Art Gallery, England

SMA:

Sauriermuseum Aathal, Switzerland

ZDM:

Zigong Dinosaur Museum, China

References

  1. Ayer, J. (2000). The Howe Ranch Dinosaurs. Aathal, Switzerland: Sauriermuseum Aathal. 96 pp.

    Google Scholar 

  2. Baden, H. P., Sviokla, S., & Roth, I. (1974). The structural protein of reptilian scales. Journal of Experimental Zoology, 187, 287–294.

    Article  Google Scholar 

  3. Bakker, R. T. (1986). The Dinosaur Heresies: New theories unlocking the mystery of the dinosaurs and their extinction. New York: William Morrow, 481 pp

  4. Bonaparte, J. F., Novas, F. E., & Coria, R. A. (1990). Carnotaurus sastrei Bonaparte, the horned, lightly build Carnosaur from the Middle Cretaceous of Patagonia. Natural History Museum of Los Angeles County, Contributions in Science, 416, 1–42.

    Google Scholar 

  5. Briggs, D. E. G. (2003). The role of decay and mineralization in the preservation of soft-bodied fossils. Annual Review of Earth and Planetary Sciences, 31, 275–301.

    Article  Google Scholar 

  6. Briggs, D. E. G., Wilby, P. R., Pérez-Moreno, B. P., Sanz, J. L., & Fregenal-Martínez, M. (1997). The mineralization of dinosaur soft tissue in the Lower Cretaceous of Las Hoyas, Spain. Journal of the Geological Society, 154, 587–588.

    Article  Google Scholar 

  7. Brown, B. (1916). Corythosaurus casuarius: Skeleton, musculature and epidermis. Bulletin of the American Museum of Natural History, 35, 709–716.

    Google Scholar 

  8. Brown, B. (1917). A complete skeleton of the horned dinosaur Monoclonius, and description of a second skeleton showing skin impressions. Bulletin of the American Museum of Natural History, 37, 281–306.

    Google Scholar 

  9. Brown, B. (1935). Sinclair dinosaur expedition, 1934. Natural History, 36, 3–15.

    Google Scholar 

  10. Buffrénil, V. de., Farlow, J.O., & Ricqlès, A.de. (1986). Growth and function of Stegosaurus plates: Evidence from bone histology. Paleobiology, 12, 459–473.

    Google Scholar 

  11. Carpenter, K. (1998). Armor of Stegosaurus stenops, and the taphonomic history of a new specimen from Garden Park, Colorado. Modern Geology, 23, 127–144.

    Google Scholar 

  12. Carpenter, K. (2010). Species concept in North American stegosaurs . Swiss Journal of Geosciences 103 (this volume). doi:10.1007/s00015-010-0020-6

  13. Carpenter, K., Miles, C., & Cloward, K. (2001). New primitive stegosaur from the Morrison Formation, Wyoming. In K. Carpenter (Ed.), The Armored Dinosaurs (pp. 55–75). Bloomington: Indiana University Press.

  14. Carpenter, K., Sanders, F., McWhinney, L., & Wood, L. (2005). Evidence for predator–prey relationships: Example for Allosaurus and Stegosaurus. In K. Carpenter (Ed.), The Carnivorous Dinosaurs (pp. 325–350). Bloomington: Indiana University Press.

  15. Chiappe, L. M., Coria, R. A., Dingus, L., Jackson, F., Chinsamy, A., & Fox, M. (1998). Sauropod dinosaur embryos from the Late Cretaceous of Patagonia. Nature, 396, 258–261.

    Article  Google Scholar 

  16. Czerkas, S. (1992). Discovery of dermal spines reveals new look for sauropod dinosaurs. Geology, 20, 1068–1070.

    Article  Google Scholar 

  17. Czerkas, S. (1997). Skin. In P. J. Currie & K. Padian (Eds.), Encyclopedia of dinosaurs (pp. 669–675). San Diego: Academic Press.

  18. Dodson, P., Behrensmeyer, A. K., Bakker, R. T., & McIntosh, J. S. (1980). Taphonomy and paleoecology of the dinosaur beds of the Jurassic Morrison Formation. Paleobiology, 6, 208–232.

    Google Scholar 

  19. Farlow, J. O., Hayashi, S., & Tattersall, G. J. (2010). Internal vascularity of the dermal plates of Stegosaurus (Ornithischia, Thyreophora). Swiss Journal of Geosciences 103 (this volume). doi:10.1007/s00015-010-0021-5

  20. Farlow, J. O., Thompson, C., & Rosner, D. (1976). Plates of the dinosaur Stegosaurus: Forced convection heat loss fins? Science, 192, 1123–1125.

    Google Scholar 

  21. Foster, J. R. (2003). Paleoecological analysis of the vertebrate fauna of the Morrison Formation (Upper Jurassic), Rocky Mountain Region, USA. New Mexico Museum of Natural History & Science Bulletin, 23, 1–95.

    Google Scholar 

  22. Gatesy, S. M., Shubin, N. H., & Jenkins, F. A., Jr. (2005). Anaglyph stereo imaging of dinosaur track morphology and microtopography. Palaeontologia Electronica, 8, 1–12.

    Google Scholar 

  23. Gilmore, C. W. (1914). Osteology of the armored Dinosauria in the United States National Museum, with special reference to the genus Stegosaurus. United States National Museum Bulletin, 89, 1–143.

    Google Scholar 

  24. Hagan, A., & Heath, J. (1980). Regulation of heat loss in the duck by vasomotion in the bill. Journal of Thermal Biology, 5, 95–101.

    Article  Google Scholar 

  25. Hayashi, S., Carpenter, K., & Suzuki, D. (2009). Different growth patterns between the skeleton and osteoderms of Stegosaurus (Ornithischia: Thyreophora). Journal of Vertebrate Paleontology, 29, 123–131.

    Article  Google Scholar 

  26. Hieronymus, T. L., Witmer, L. M., Tanke, D. H., & Currie, P. J. (2009). The facial integument of Centrosaurine Ceratopsids: Morphological and histological correlates of novel skin structures. The Anatomical Record, 292, 1370–1396.

    Article  Google Scholar 

  27. Hoefs, M. (2000). The thermoregulatory potential of Ovis horn cores. Canadian Journal of Zoology, 78, 1419–1426.

    Article  Google Scholar 

  28. Hooley, R. W. (1917). On the integument of Iguanodon bernissartensis Boulenger, and of Morosaurus becklesii Mantell. Geological Magazine, 6, 148–150.

    Article  Google Scholar 

  29. Ikejiri, T. (2005). Distribution and Biochronology of Camarasaurus (Dinosauria, Sauropoda) from the Jurassic Morrison Formation in the Rocky Mountain Region. In New Mexico Geological Society, 56th Field Conference Guidebook, Geology of the Chama Basin (pp. 367–379).

  30. Keller, T. (1992). «Weichteil-Erhaltung» bei grösseren Vertebraten (Ichthyosauriern) des Posidonienschiefers Holzmadens (Oberer Lias, Mesozoikum Süddeutschlands). Kaupia, 1, 23–63.

    Google Scholar 

  31. Kirkland, J. I., & Carpenter, K. (1994). North America’s first pre-Cretaceous ankylosaur (Dinosauria) from the Upper Jurassic Morrison Formation of Western Colorado. Brigham Young University Geological Studies, 40, 25–42.

    Google Scholar 

  32. Maidment, S., Norman, D., Barrett, P., & Upchurch, P. (2008). Systematics and phylogeny of Stegosauria (Dinosauria: Ornithischia). Journal of Systematic Paleontology, 6, 367–407.

    Article  Google Scholar 

  33. Main, R., Ricqlès, A. de, Horner, J., & Padian, K. (2005). The evolution and function of thyreophoran dinosaur scutes: Implications for plate function in stegosaurs. Paleobiology, 31, 291–314.

    Google Scholar 

  34. Mallison, H. (2010). CAD assessment of the posture and range of motion of Kentrosaurus aethiopicus HENNIG 1915. Swiss Journal of Geosciences, 103 (this volume). doi:10.1007/s00015-010-0024-2

  35. Marsh, O. C. (1877). A new order of extinct Reptilia (Stegosauria) from the Jurassic of the Rocky Mountains. American Journal of Science, 14(3rd series), 513–514.

    Google Scholar 

  36. Marsh, O. C. (1890). Description of new dinosaurian reptiles. American Journal of Science 38(3rd series), 81–86.

    Google Scholar 

  37. Martill, D. M., Batten, D. J., & Loydell, D. K. (2000). A new specimen of the thyreophoran dinosaur cf. Scelidosaurus with soft tissue preservation. Palaeontology, 43, 549–559.

    Article  Google Scholar 

  38. Mateus, O., Maidment, S. C. R., & Christiansen, N. A. (2009). A new long-necked ‘sauropod-mimic’ stegosaur and the evolution of the plated dinosaurs. Proceedings of the Royal Society B, 276, 1815–1821.

    Article  Google Scholar 

  39. Mateus, O., & Milàn, J. (2009). A divers Upper Jurassic dinosaur ichnofauna from central-west Portugal. Lethaia, 43, 245–257.

    Article  Google Scholar 

  40. Mateus, O., Milàn, J., Romano, M., & Whyte, M. A. (2010). New finds of stegosaurid tracks from the Upper Jurassic Lourinhã Group, central-west Portugal: Implications for the spatial, temporal and palaeoecological distribution of the morphotype Deltapodus. Acta Palaeontologica Polonica (in press).

  41. McCrea, R. T., Lockley, M. G., & Meyer C. A. (2001). Global distribution of purported ankylosaur track occurrences. In K. Carpenter (Ed.), The Armored Dinosaurs (pp. 413–454). Bloomington: Indiana University Press.

  42. Myers, T. S., & Storrs, G. W. (2007). Taphonomy of the Mother’s Day Quarry, Upper Jurassic Morrison Formation, South-Central Montana, USA. Palaios, 22, 5–123.

    Google Scholar 

  43. Penkalski, P. (2001). Variation in specimens referred to Euoplocephalus tutus. In K. Carpenter (Ed.), The Armored Dinosaurs (pp. 261–297). Bloomington: Indiana University Press.

  44. Picard, K., Festa-Bianchet, M., & Thomas, D. (1996). The cost of horniness: Heat loss may counter sexual selection for large horns in temperate bovids. Ecoscience, 3, 280–284.

    Google Scholar 

  45. Picard, K., Thomas, D., Festa-Bianchet, M., Belleville, F., & Laneville, A. (1999). Differences in the thermal conductance of tropical and temperate bovid horns. Ecoscience, 6, 148–158.

    Google Scholar 

  46. Pinegar, R. T., Loewen, M. A., Cloward, K. C., Hunter, R. J., & Weege, C. J. (2003). A juvenile allosaur with preserved integument from the basal Morrison Formation of Central Wyoming. Journal of Vertebrate Paleontology, 23(Suppl. 3), 87A–88A.

    Google Scholar 

  47. Platt, B. F., & Hasiotis, S. T. (2006). Newly discovered sauropod dinosaur tracks with skin and foot-pad impressions from the Upper Jurassic Morrison Formation, Bighorn Basin, Wyoming, USA. Palaios, 21, 249–261.

    Article  Google Scholar 

  48. Powell, J. E. (1980). Sobre la presencia de una armadura dermica en algunos dinosaurios titanosauridos. Acta Geologica Lilloana, 15, 41–47.

    Google Scholar 

  49. Schwarz, D., Ikejiri, T., Breithaupt, B. H., Sander, P. M., & Klein, N. (2007). A nearly complete skeleton of an early juvenile diplodocid (Dinosauria: Sauropoda) from the Lower Morrison Formation (Late Jurassic) of north central Wyoming and its implications for early ontogeny and pneumaticity in sauropods. Historical Biology, 19, 225–253.

    Article  Google Scholar 

  50. Siber, H. J. & Möckli, U. (2009). The Stegosaurs of the Sauriermuseum Aathal. Aathal, 56 pp.

  51. Sternberg, C. M. (1925). Integument of Chasmosaurus belli. Canadian Field Naturalist, 39, 108–110.

    Google Scholar 

  52. Tattersall, G., Andrade, D., & Abe, A. (2009). Heat exchange from the toucan bill reveals a controllable vascular thermal radiator. Science, 325, 468–470.

    Article  Google Scholar 

  53. Tschopp, E. (2008). The complete set of autopodia of the Camarasaurus SMA 0002 and what it can tell us about systematics, taphonomy, ontogeny, and footprint shape. Unpublished Master Thesis, University of Zurich, Switzerland, 185 pp.

  54. Turner, C. E. & Peterson, F. (1999). Biostratigraphy of dinosaurs in the Upper Jurassic Morrison Formation of the Western Interior, USA. In D. D. Gillette. (Ed.), Vertebrate Paleontology in Utah (pp. 77–114). Utah Geological Survey Miscellaneous Publication, no. 99-1, Utah Geological Survey, Salt Lake City.

  55. Turner, C. E., & Peterson, F. (2004). Reconstruction of the Upper Jurassic Morrison Formation extinct ecosystem—a synthesis. Sedimentary Geology, 167, 309–355.

    Article  Google Scholar 

  56. Vickaryous, M. K., & Sire, J.-Y. (2009). The integumentary skeleton of tetrapods: Origin, evolution, and development. Journal of Anatomy, 214, 441–464.

    Article  Google Scholar 

  57. White, T. E. (1967). Dinosaurs at home. New York: Vantage Press, 232 pp

  58. Xing, L. D., Peng, G. Z., & Shu, C. K. (2008). Stegosaurian skin impressions from the Upper Jurassic Shangshaximiao Formation, Zigong, Sichuan, China: A new observation. Geological Bulletin of China, 27, 1049–1053. (in Chinese with English abstract).

    Google Scholar 

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Acknowledgments

We thank Hans-Jakob Siber (Sauriermuseum Aathal) for having invited us and encouraged our study on the stegosaurian integument impressions of the SMA. We are also grateful to the field team of SMA for having found and preserved the integument impressions, notably to the preparators Ben Pabst and Esther Premru. The manuscript benefited greatly from the comments and suggestions of Octávio Mateus (Universidade Nova de Lisboa; Museu da Lourinhã, Portugal), Rui Castanhinha (Instituto Gulbenkian de Ciência; Museu da Lourinhã, Portugal), James Farlow (Indiana University, Fort Wayne, Indiana, USA), and Stephen Brusatte (American Museum of Natural History, New York, USA) who kindly reviewed earlier versions of the manuscript, as well as of those of the two reviewers Matt Vickaryous (Department of Biomedical Sciences, University of Guelph, Ontario, Canada) and Kenneth Carpenter (College of Eastern Utah Prehistoric Museum, Price, Utah, USA). We are grateful to James Farlow, Shoji Hayashi, Octávio Mateus, Jesper Milàn, Kenneth Carpenter as well as Jacques Ayer for sharing their unpublished manuscripts with us, and for letting us incorporate some of their results into our work. We also thank Hans-Jakob Siber and Esther Premru for the permission to use their quarry map of SMA 0018, and Urs Möckli for providing us with high quality photos of the skin impressions.

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Correspondence to Nicolai A. Christiansen.

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Editorial handling: Jean-Paul Billon-Bruyat & Daniel Marty.

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Christiansen, N.A., Tschopp, E. Exceptional stegosaur integument impressions from the Upper Jurassic Morrison Formation of Wyoming. Swiss J Geosci 103, 163–171 (2010). https://doi.org/10.1007/s00015-010-0026-0

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Keywords

  • Hesperosaurus mjosi
  • Stegosauria
  • Skin impressions
  • Integument
  • Keratinous covering
  • Morrison Formation