Compagicrinus fenestratus, a new Lower Ordovician inadunate crinoid from North Greenland

Abstract

Compagicrinus n.gen., from the Nunatami Formation (Arenig) of Washington Land, North Greeniand, is assigned to the arder Dendrocrinina. A unique arrangement of piates in the cup is intermediate between those of Aethocrinus (L. Arenig) and Dendrocrinus (M. Ordovician - M. Silurian). The plate arrangement of Aethocrinus is reinterpreted. Compagicrinus may have given rise to the arder Cyathocrinina via Carabocrinus. It is suggested that the usuai radianai of dicyclic inadunates arose from the super-radianal of Compagicrinus and not the infer-radiai of the C ray.