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Comparison of flattened Blastozoan echinoderms: Insights from the new Early Ordovician Eocrinoid Haimacystis rozhnovi

Published online by Cambridge University Press:  20 May 2016

Colin D. Sumrall
Frederick and Amey Geier Collections and Research Center, Museum of Natural History & Science, Cincinnati Museum Center, 1720 Gilbert Avenue, Cincinnati, Ohio 45202,
James Sprinkle
Department of Geological Sciences, University of Texas, Austin, 78712,
Thomas E. Guensburg
Math and Physical Sciences Division, Rock Valley College, Rockford, Illinois 61114,


A new, flattened, eocrinoid-grade, blastozoan echinoderm Haimacystis rozhnovi new genus and species is described from the uppermost Lower Ordovician Wah Wah Limestone of western Utah. Although apparently most similar in morphology to the rhipidocystids, Haimacystis differs in its plane of thecal flattening, lack of one-piece marginals, and ambulacral system development. A comparison of overall morphology and plane of thecal flattening is presented for flattened blastozoans. Haimacystis was a streamlined suspension feeder attached to the sea floor by a holdfast at the end of a relatively short stem and bent over in the water column in moderate currents.

Research Article
Copyright © The Paleontological Society

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Present address—Department of Geoscience, University of Iowa, Iowa City, 52242.


Dean, J., and Smith, A. B. 1998. Paleobiology of the primitive pelmatozoan echinoderm Cardiocystites . Palaeontology, 41:11831194.Google Scholar
Guensburg, T. E., and Sprinkle, J. 1992. Rise of echinoderms in the Paleozoic Evolutionary Fauna: Significance of paleoenvironmental controls. Geology, 20:407410.2.3.CO;2>CrossRefGoogle Scholar
Hintze, L. F. 1973. Lower and Middle Ordovician stratigraphic sections in the Ibex Area, Millard County, Utah. Brigham Young University Geology Studies, 20:336.Google Scholar
Jaekel, O. 1918. Phylogenie und system der Pelmatozoen. Paläontologische Zeitschrift, 3:1128.CrossRefGoogle Scholar
Lewis, R. D., Sprinkle, J., Bailey, J. B., Moffit, J., and Parsley, R. L. 1987. Mandalocystis, a new rhipidocystid eocrinoid from the Whiterockian Stage (Ordovician) in Oklahoma and Nevada. Journal of Paleontology, 61:12221235.CrossRefGoogle Scholar
Patterson, C. 1982. Morphological characters and homology, p. 2174. In Joysey, K. A. and Friday, A. E. (eds.), Systematics Association Special Volume 21: Problems of Phytogeny Reconstruction. Academic Press, New York.Google Scholar
Rozhnov, S. V. 1989. New data about rhipidocystids (Eocrinoidea), p. 3857. In Kaljo, D. L. (ed.), Fossil and Recent Echinoderm Researches. Academy of Sciences of the Estonian SSR, Tallinn (In Russian).Google Scholar
Rozhnov, S. V. 1992. Rhipidocystis Jaekel, 1901 (Echinodermata, Eocrinoidea): proposed designation of R. baltica Jaekel, 1901 as type species. Bulletin of Zoological Nomenclature, 49:4142.Google Scholar
Rozhnov, S. V. 1994. Comparative morphology of Rhipidocystis Jaekel, 1900 and Cryptocrinites von Buch, 1840 (Eocrinoidea; Ordovician), p. 173178. In Bruno, D., Guille, A., Féral, J., and Roux, M. (eds.), Echinoderms through Time. Balkema, Rotterdam.Google Scholar
Sprinkle, J. 1973a. Morphology and Evolution of Blastozoan Echinoderms. Harvard University Museum of Comparative Zoology, Special Publication, 283 p.Google Scholar
Sprinkle, J. 1973b. A new occurrence of the Ordovician eocrinoid Lingulocystis from Bolivia, South America. Journal of Paleontology, 47:11131116.Google Scholar
Sprinkle, J., and Guensburg, T. E. 1995. Origin of echinoderms in the Paleozoic Evolutionary Fauna: The role of substrates. Palaios, 10:437453.CrossRefGoogle Scholar
Sumrall, C. D. 1996. A phylogenetic analysis of Echinodermata based on primitive fossil taxa. Unpublished Ph.D. Dissertation, University of Texas at Austin, 360 p.Google Scholar
Sumrall, C. D. 1997. The role of fossils in the phylogenetic reconstruction of Echinodermata, p. 267288. In Waters, J. A. and Maples, C. G. (eds.), Geobiology of Echinoderms. Paleontological Society Papers, 3.Google Scholar
Ubaghs, G. 1960. Le genre Lingulocystis Thoral (Echinodermata, Eocrinoidea), avec des remarques critiques sur la position systématique du genre Rhipidocystis Jaekel. Annates Paléontologie, 46:81116.Google Scholar