BIODIVERSITY AND HISTORICAL BIOGEOGRAPHY OF STALKED CRINOIDS (ECHINODERMATA) IN THE DEEP-SEA

About 95 species of stalked crinoids are now described from 60 m to ha dal depths, but our knowledge remains far from complete. Depending on which species concept is used, estimates of species richness can be dr amatically different, It is necessary to have a homogeneous concept fo r taxonomic units. The abundance of the crinoid fossil record allows a discussion of the ancestry of deep sea crinoid fauna. Stalked crinoid s have a horizontal diversity pattern with three regional centres of h igh diversity (i.e. western tropical Pacific, western tropical Atlanti c and north-eastern Atlantic). Vertical patterns show two faunal strat a which vary in importance among provinces. The epibathyal stratum has apparently remained relatively similar in intertropical areas since t he Mesozoic. Despite environmental changes related to glaciation since the Middle Miocene, the deepest crinoid fauna (i.e. the deep sea faun a sensu stricto at depths more than 1000 +/- 200 m) have a very ancien t origin with a dispersion closely related to plate tectonics. The bat hyal fauna on hard substrates includes a few living fossils and has a high historical interest.