Column regeneration in an Ordovician crinoid (Echinodermata): paleobiologic implications

Abstract

The crinoid column is a paradox of crinoid paleontology. The crown is required for taxonomic identification and, therefore, prerequisite for phylogenetic, paleoecologic, or other studies. However, column elements (columnals and pluricolumnals) are by far the most common crinoidal fossil remains. The biostratigraphic utility of crinoid columns has been demonstrated in some cases (e.g., Donovan, 1984), but this is done with the risk of developing a parataxonomy among crinoids because in most cases columnals are not associated with crowns and, therefore, cannot be assigned to crown species with certainty.