CYATHIDIUM-PLANTEI SP-N, AN EXTANT CYRTOCRINID (ECHINODERMATA, CRINOIDEA) - MORPHOLOGICALLY IDENTICAL TO THE FOSSIL CYATHIDIUM-DEPRESSUM (CRETACEOUS, CENOMANIAN)

A new species of the holopodid genus Cyathidium was found on rocks off Grande Comore in a depth of around 200 m. Based on external morpholog y of resting animals, the new species Cyathidium plantei sp. n is desc ribed, with emphasis on comparison to the only other extant species (C . foresti) as well as to the four extinct representatives of the genus . Concerning morphological characters, the new species is almost ident ical to the Cretaceous C. depressum. A cladistic analysis of the entir e family, including the genus Holopus, shares a peculiar pattern of be nding of the arms, which in principle is an apomorphic character of th e family and in detail shows variations within the family. In addition , stratigraphic data are used for the determination of the evolutionar y direction. This analysis reveals that the two recent species are clo sely related to each other, and to the fossil C. depressum, from which the entire family is probably derived. (C) 1996 The Norwegian Academy of Science and Letters.