Phenotypic convergence among pentacrinid crinoids related to environmentalpressure.

Morphological converging and diverging trends are demonstrated using detail ed biometric analyses of the skeleton in pentacrinid populations of the Dip locrininae subfamily living in tropical western Atlantic and in the Pacific Ocean. According to environmental data obtained by in situ submersible obs ervations, water flow characteristics (laminar or with eddies) appear to be the main factor controlling phenotypes through ontogeny. Evidence of conve rgence between different taxa may be explained by ecological niches with ed dies. (C) 2000 Academie des sciences/Editions scientifiques et medicales El sevier SAS.