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

Abstract

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.

Type
Research Article
Copyright
Copyright © The Paleontological Society

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Footnotes

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

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