OPHIUROID PHYLOGENY AND HIGHER TAXONOMY - MORPHOLOGICAL, MOLECULAR AND PALEONTOLOGICAL PERSPECTIVES

A cladistic analysis of the class Ophiuroidea at subfamily level is pr esented based on a morphological data base of 43 characters. The tree is rooted using the best known fossil member of the stem-group. This i dentifies Ophiocanopidae as sister group to other extant ophiuroids, w hich themselves fall into two major groups, the Ophiurida and the Eury alida. Although our most parsimonious solution is highly resolved, not all parts of the cladogram are well supported. Molecular data from th e 5' end of the large subunit ribosomal RNA molecule are presented for 10 taxa, with representatives from major higher groupings. This provi des some support for the morphological tree, but leaves most of the de ep branches unresolved. A phylogenetic tree is constructed for ophiuro ids by selecting one of the cladograms as our working hypothesis and c alibrating this against the stratigraphic record of the group. A revis ed taxonomy for the group is presented and the new taxon Ophiodermatin a is erected.