Crinoids were at their most diverse and widespread during the Palaeozoic. Large-stemmed benthic crinoids dominated shallow marine environments. Modern crinoids are limited to pseudoplanktonic forms in deep water environments. One reason for this shift put forward has been increased grazing and predation pressure brought about by the Mesozoic Marine Revolution (MMR) in the late Jurassic and Cretaceous... Read more


  • Phylum: Echinodermata
  • Class: Crinoidea

Diagnostic features

These are the features that will help you to identify fossils as crinoids.

  • Crown
  • Stalk
  • Pentaradial symmetry
  • Ossicles
  • Calyx
  • Pinnules
  • Holdfast

Stratigraphic range

Ordovician to present