The end-Ordovician extinctions had a profound effect on shallow-water benthic communities, including the Crinoidea. A hard-won recovery after the extinctions led (not surprisingly) to macroevolutionary turnover in crinoid faunas. We do not have many of these exposures to study this impactful moment in our evolutionary history and our opportunity to see this transition in Canada is special indeed. Anticosti Island is the most complete Ordovician-Silurian boundary section recording shallow-water habitats.
Both new taxa and changes in Anticosti Island stratigraphic nomenclature are addressed in the paper. New taxa include Becsciecrinus groulxi n. sp., Bucucrinus isotaloi n. sp., Jovacrinus clarki n. sp., Plicodendrocrinus petryki n. sp., Plicodendrocrinus martini n. sp., Thalamocrinus daoustae n. sp., and Lateranicrinus saintlaurenti n. gen. n. sp.
The status of Xenocrinus rubus as a boundary-crossing taxon is confirmed, range extensions of several taxa are documented, and the distribution of crinoids with the revised stratigraphic nomenclature is documented. This publication is a labour of love covering many years of a collaborative effort by Cournoyer and William Ausich. Definitely give it a read: