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
These are the features that will help you to identify fossils as crinoids.
- Pentaradial symmetry
Ordovician to present