Advertisement

Swiss Journal of Palaeontology

, Volume 137, Issue 2, pp 205–210 | Cite as

Form and function of the strangest crinoid stem: Devonian of Morocco

  • Stephen K. DonovanEmail author
  • Johnny A. Waters
  • Mark S. Pankowski
Regular Research Article

Abstract

Trombonicrinus (col.) hanshessi gen. et sp. nov. is a crinoid species of unusual morphology and is based solely on the stem. It comes from the (probably Lower) Devonian of Tafraoute, Anti Atlas Mountains, Morocco. It is a long crinoid stem of circular section, tapering distally throughout, with a tight curvature through 180º between the mesistele and proxistele; attachment is distally by short, pointed, unsegmented pseudoradices. The overall appearance is reminiscent of the slide of a trombone. The dististele is essentially straight, the mesistele is more or less convoluted, and the proxistele is straight and parallels the more distal stem. The dististele was attached to an upright object around which the pseudoradices formed a close attachment. The crinoid’s stem was growing down towards the substrate. The mesistele was free of the attachment surface and grew in a more convoluted manner. The proxistele was adapted to elevate the crown, growing upwards and in the opposite direction of the rest of the crinoid. This is a form unique to T. (col.) hanshessi and not recognised hitherto in the Crinoidea. The conical, most proximal part of this stem in the holotype may suggest that it was immediately beneath the cup; the specimen is considered complete apart from the crown. The loss of the crown was most likely the result of autotomy. Although the proxistele of the paratype is relatively longer, it is probably incomplete. This crinoid was either a cladid or a camerate.

Keywords

Trombonicrinus (col.) Tafraoute Functional morphology Life orientation Attachment Pseudoradices 

Notes

Acknowledgements

This paper is a contribution to IGCP 596. The paratype was photographed by C. Gonzalez at Appalachian State University. Thoughtful reviews by Professors Gary D. Webster (Washington State University, Pullman) and William I. Ausich (The Ohio State University, Columbus) are gratefully acknowledged.

References

  1. Ager, D. V. (1963). Principles of Paleoecology. New York: McGraw-Hill.Google Scholar
  2. Ausich, W. I. (1986). Palaeoecology and history of the Calceocrinidae (Palaeozoic Crinoidea). Palaeontology, 29, 85–99.Google Scholar
  3. Austin, T., & Austin, T., Jr. (1843). Description of several new genera and species of Crinoidea. Annals and Magazine of Natural History (series 1), 11, 195–207.CrossRefGoogle Scholar
  4. Brower, J. C. (1966). Functional morphology of Calceocrinidae with description of some new species. Journal of Paleontology, 40, 613–634.Google Scholar
  5. Brower, J. C. (1985). Ontogeny and functional morphology of two Ordovician calceocrinids. In B. F. Keegan, & B. D. S. O’Connor (Eds.), Echinodermata: Proceedings of the Fifth International Echinoderm Conference, Galway, 2429 September, 1984 (pp. 13–18). Rotterdam: A. A. Balkema.Google Scholar
  6. Donovan, S. K. (1986). Pelmatozoan columnals from the Ordovician of the British Isles. Part 1. Monographs of the Palaeontographical Society, London, 138(568), 1–68.Google Scholar
  7. Donovan, S. K. (1993). Contractile tissues in the cirri of ancient crinoids: criteria for recognition. Lethaia, 26, 163–169.CrossRefGoogle Scholar
  8. Donovan, S. K. (2011a). Spineless displays or why inaccurate restorations of fossil invertebrates discredit our museums. Geological Curator, 9, 279–284.Google Scholar
  9. Donovan, S. K. (2011b). The poorly illustrated crinoid. Lethaia, 44, 125–135.CrossRefGoogle Scholar
  10. Donovan, S. K. (2012). Was autotomy a pervasive adaptation of the crinoid stalk during the Palaeozoic? Geology, 40, 867–870.CrossRefGoogle Scholar
  11. Donovan, S. K. (2016). Problematic aspects of the form and function of the stem in Palaeozoic crinoids. Earth-Science Reviews, 154, 174–182.CrossRefGoogle Scholar
  12. Donovan, S. K., & Fearnhead, F. E. (2014). A dearth of diplobathrids (Crinoidea) from the type Devonian System, south-west England. Proceedings of the Yorkshire Geological Society, 60, 91–97.CrossRefGoogle Scholar
  13. Donovan, S. K., & Fearnhead, F. E. (in press). The British Devonian Crinoidea. Part 2, addendum to Part 1, Cladida, Disparida and columnals. Monograph of the Palaeontographical Society, London.Google Scholar
  14. Donovan, S. K., & Sevastopulo, G. D. (1989). Myelodactylid crinoids from the Silurian of the British Isles. Palaeontology, 32, 689–710.Google Scholar
  15. Donovan, S. K., Widdison, R. E., Lewis, D. N., & Fearnhead, F. E. (2012). The British Silurian Crinoidea. Part 3, addendum to parts 1 and 2, Camerata and columnals. Monograph of the Palaeontographical Society, London, 166(638), 135–259.Google Scholar
  16. Feist, R., & Chatterton, B. D. E. (2015). Kolihapeltine trilobites, the spiniest scutellids from the eastern Anti-Atlas (Morocco, Early Devonian): evolution, environment and classification. Papers in Palaeontology, 1, 255–287.CrossRefGoogle Scholar
  17. Haude, R. (1972). Bau und Funktion der Scyphocrinites-Lobolithen. Lethaia, 5, 95–125.CrossRefGoogle Scholar
  18. Haude, R. (1992). Scyphocrinoiden, die Bojen-Seelilien im hohen Silur-tiefen Devon. Paleontographica Abteilung A, Palaeozoologie und Stratigraphie, 222, 141–187.Google Scholar
  19. Hess, H. (1999). Recent. In H. Hess, W. I. Ausich, C. E. Brett, & M. J. Simms (Eds.), Fossil Crinoids (pp. 237–244). Cambridge: Cambridge University Press.CrossRefGoogle Scholar
  20. Klug, C., De Baets, K., Naglik, C., & Waters, J. (2014). New species of Tiaracrinus from the latest Emsian of Morocco. Acta Palaeontologica Polonica, 59, 135–145.Google Scholar
  21. Little, W., Fowler, H. W., & Coulson, J. (1983). The Shorter Oxford Dictionary on Historical Principles. In C. T. Onions, G. W. Friedrichsen (Eds.) Marl-Z and Addenda. Volume II, 3rd ed. (pp. 1281–2672). Oxford: Oxford University Press.Google Scholar
  22. Macurda, D. B., Jr., & Meyer, D. L. (1974). The feeding posture of modern stalked crinoids (Echinodermata). Nature, 247, 394–396.CrossRefGoogle Scholar
  23. Miller, J. S. (1821). A Natural History of the Crinoidea or Lily-Shaped Animals, with Observations on the Genera Asteria, Eurayle, Comatula and Marsupites (pp. 1–150). Bristol: C. Frost.Google Scholar
  24. Moore, R. C., Jeffords, R. M., & Miller, T. H. (1968). Morphological features of crinoid columns. University of Kansas Paleontological Contributions, Echinodermata Article, 8, 1–30.Google Scholar
  25. Moore, R. C., Ubaghs, G., Rasmussen, H. W., Breimer, A. & Lane, N. G. (1978). Glossary of crinoid morphological terms. In Moore, R. C. & Teichert, C. (Eds), Treatise on Invertebrate Paleontology, Part T, Echinodermata 2(1). Geological Society of America and University of Kansas, Boulder and Lawrence, T229, T231, T233—T242.Google Scholar
  26. Morris, J. (1843). A Catalogue of British Fossils comprising all the Genera and Species hitherto described; With reference to their Geological Distribution and to the Localities in which they have been found. London: John Van Voorst.CrossRefGoogle Scholar
  27. Simms, M. J. (1986). Contrasting lifestyles in Lower Jurassic crinoids: a comparison of benthic and pseudopelagic Isocrinida. Palaeontology, 29, 475–493.Google Scholar
  28. Webster, G. D. (1974). Crinoid pluricolumnal noditaxis patterns. Journal of Paleontology, 48, 1283–1288.Google Scholar
  29. Webster, G. D., & Becker, R. T. (2009). Devonian (Emsian to Frasnian) crinoids of the Dra Valley, western Anti-Atlas Mountains, Morocco. In P. Königsdorf (Ed.), Devonian Change: Case Studies in Palaeogeography and Palaeoecology (vol. 314, pp. 131–148). London: Geological Society London Special Publications.Google Scholar
  30. Webster, G. D., Becker, R. T., & Maples, C. G. (2005). Biostratigraphy, paleoecology and taxonomy of Devonian (Emsian and Famennian) crinoids from southeastern Morocco. Journal of Paleontology, 79, 1052–1071.CrossRefGoogle Scholar
  31. Weller, S., & Davidson, A. D. (1896). Petalocrinus mirabilis (n. sp.) and a new American fauna. Journal of Geology, 4, 166–173.CrossRefGoogle Scholar
  32. Wulff, J. I., & Ausich, W. I. (1989). Growth of the xenomorphic crinoid column (Taxocrinus, Late Mississippian). Journal of Paleontology, 63, 657–662.CrossRefGoogle Scholar
  33. Zenker, J. C. (1833). Organische Reste (Petrefacten) aus der Altenburger Braunkohlen-Formation etc. Beiträge zur Naturgeschite Urwelt, Jena, (pp. 1–67).Google Scholar

Copyright information

© Akademie der Naturwissenschaften Schweiz (SCNAT) 2018

Authors and Affiliations

  • Stephen K. Donovan
    • 1
    Email author
  • Johnny A. Waters
    • 2
  • Mark S. Pankowski
    • 3
  1. 1.Taxonomy and Systematics GroupNaturalis Biodiversity CenterRA LeidenThe Netherlands
  2. 2.Department of Geological and Environmental SciencesAppalachian State UniversityBooneUSA
  3. 3.RockvilleUSA

Personalised recommendations