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The role of spines in preventing structural damage to echinoid tests

Published online by Cambridge University Press:  08 February 2016

Richard R. Strathmann
Richard R. Strathmann*
Affiliation:
Department of Zoology and Friday Harbor Laboratories, University of Washington, Friday Harbor, Washington 98250
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Extract

Living echinoids provide a structural analogue to the rigid thecae of many extinct echinoderms and are here used to examine some consequences of the increased rigidity and decreased number of plates which occurred in several lineages of echinoderms. A special feature of the echinoids is the large spines which protect the echinoid tests from failure under impact. The spines absorb energy or spread loads because the spines break or the tissue connecting the spine to the test is stretched or torn. Spines that absorb impacts might be superfluous in echinoderms encased in a rigid test or theca if they have flexible stems or are in low energy habitats, but spines should be useful to stemless thecate echinoderms on hard substrata. In the absence of spines, a flexible theca of overlapping plates might be superior to a rigid theca. Greater rigidity does not necessarily provide greater protection.

Tracts of podial pores are sites of weakness in all tests examined [Eucidaris tribuloides (Lamarck), Echinometra viridis Agassiz, Diadema antillarum Philippi, Lytechinus variegatus (Lamarck), Tripneustes ventricosus (Lamarck)]. Therefore arrangement of pores affects strength of rigid thecae. Sutures are stronger than plates in most species examined, but cracks cross sutures, and tests of E. tribuloides frequently break along sutures. It is not yet proven that sutures increase toughness of rigid tests by relieving stress on plates or stopping cracks. If resisting failure under impact is important, then preconditions for acquiring rigidity are life in a low energy habitat or accessory structures which absorb or spread impacts.

Type
Articles
Information
Paleobiology , Volume 7 , Issue 3 , Summer 1981 , pp. 400 - 406
Copyright
Copyright © The Paleontological Society 

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References

Literature Cited

Benson, R. H. 1975. Morphologic stability in Ostracoda. Bull. Am. Paleontol. 65:13–46.Google Scholar
Burkhardt, A. and Märkel, K. 1980. Statics of the primary spines of Diadematidae. Pp. 85–87. In: Jangoux, M., ed. Echinoderms: Past and Present. A. A. Balkema; Rotterdam.Google Scholar
Currey, J. D. 1967. The failure of exoskeletons and endoskeletons. J. Morph. 123:1–16.CrossRefGoogle ScholarPubMed
Currey, J. D. 1975. A comparison of the strength of echinoderm spines and mollusc shells. J. Mar. Biol. Assoc. U.K. 55:419–424.CrossRefGoogle Scholar
Dayton, P. K. 1973. Two cases of resource partitioning in an intertidal community: making the right prediction for the wrong reason. Am. Nat. 107:662–670.CrossRefGoogle Scholar
Ebert, T. A. 1965. A technique for the individual marking of sea urchins. Ecology. 46:193–194.CrossRefGoogle Scholar
Ebert, T. A. 1968. Growth rates of the sea urchin Strongylocentrotus purpuratus related to food availability and spine abrasion. Ecology. 49:1075–1091.CrossRefGoogle Scholar
Gordon, J. E. 1978. Structures. Or Why Things Don't Fall Down. 395 pp. Penguin; New York.CrossRefGoogle Scholar
Kier, P. M. 1965. Evolutionary trends in Paleozoic echinoids. J. Paleontol. 39:436–465.Google Scholar
Kier, P. M. 1974. Evolutionary trends and their functional significance in the post-Paleozoic echinoids. J. Paleontol. 48, Suppl. to no. 3:1–95.CrossRefGoogle Scholar
Kier, P. M. 1975. The echinoids of Carrie Bow Cay, Belize. Smithsonian Contrib. Zool. 206:1–45.CrossRefGoogle Scholar
Moore, R. C., ed. 1966. Treatise on Invertebrate Paleontology, Part U, Echinodermata. 695 pp. Geol. Soc. Am. and Univ. Kansas Press.Google Scholar
Moore, R. C., ed. 1967. Treatise on Invertebrate Paleontology, Part S, Echinodermata. 650 pp. Geol. Soc. Am. and Univ. Kansas Press.Google Scholar
Moss, M. L. and Meehan, M. 1967. Sutural connective tissues in the test of an echinoid Arbacia punctulata. Acta Anat. 66:279–304.Google ScholarPubMed
Moss, M. L. and Meehan, M. 1968. Growth of the echinoid test. Acta Anat. 69:409–444.CrossRefGoogle ScholarPubMed
Paul, C. R. C. 1979. Early echinoderm radiation. Pp. 415–434. In: House, M. R., ed. The Origin of Major Invertebrate Groups. Academic Press; New York.Google Scholar
Randall, J. E., Schroeder, R. E., and Starck, W. A. II. 1964. Notes on the biology of the echinoid Diadema antillarum. Carib. J. Sci. 4:421–433.Google Scholar
Raup, D. M. 1968. Theoretical morphology of echinoid growth. J. Paleont. 42(Suppl.):50–63.CrossRefGoogle Scholar
Salvadori, M. with Heller, R. 1963. Structure in Architecture. 370 pp. Prentice Hall; New Jersey.Google Scholar
Seilacher, A. 1979. Constructional morphology of sand dollars. Paleobiology. 5:191–221.CrossRefGoogle Scholar
Smith, A. B. 1980. Stereom microstructure of the echinoid test. Spec. Papers Palaeontol. 25. 81 pp. Palaeontol. Assoc. London.Google Scholar
Wainwright, S. A., Biggs, W. D., Currey, J. D., and Gosline, J. M. 1976. Mechanical Design in Organisms. 423 pp. Wiley; New York.Google Scholar