Bulletin of the Mizunami Fossil Museum

Bulletin of the Mizunami Fossil Museum No. 48

The multi-component skeletons of many groups of organisms, such as plants, arthropods, echi-noderms and vertebrates, are commonly found disintegrated into separate elements in the fossil record. A　new Early to Late Devonian crinoid morphospecies, Pseudobystrowicrinus (col.) fionae gen. et sp. nov., based on disarticulated columnals, is known from in-situ occurrences in south-west England and as float (erratics) of Pleistocene forerunners of the present-day River Maas (Meuse) in the province of Limburg, the Netherlands. Specimens are commonly preserved in sandstones. Columnals are probably derived from the mesistele; they are large nodals with rounded epifacets and also a small, central, pentagonal, lumen with a symplectial perilumen. The most distinctive feature is a broad, deep, pentastellate areola, appearing like a wide, Bystrowicrinus-like lumen in natural moulds. The column is heteromorphic; nodals are robust. This particular crinoid was likely a cladid or camerate adapted to high-energy environments.