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An anomalous specimen of the unstalked Cretaceous crinoid Uintacrinus socialis Grinnell, 1876: regeneration or taphonomy?

Published online by Cambridge University Press:  19 May 2016

Jay A. Schneider
Jay A. Schneider*
Affiliation:
Department of Geophysical Sciences, University of Chicago, Illinois 60637
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Abstract

A specimen of the unstalked Cretaceous crinoid Uintacrinus socialis Grinnell, 1876, has a theca with an anomalous appearance that may be attributed to either inaccurate regeneration or unusual taphonomy. The former would entail regeneration of brachials from pinnulars, and inaccurate regeneration of the arms themselves. The latter would imply that the theca was broken into at least three pieces, and then the pieces were rotated with respect to each other. The presence of broken plates and sediment in the line of breakage indicates that the specimen was broken after death, and the taphonomic explanation is favored. Of the hundreds of known specimens of this species, this is the only one with such an appearance.

Type
Research Article
Information
Journal of Paleontology , Volume 63 , Issue 6 , November 1989 , pp. 897 - 900
Copyright
Copyright © The Paleontological Society 

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References

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