Ophiuroid phylogeny and higher taxonomy: morphological, molecular and palaeontological perspectives
Résumé
A cladistic analysis of the class Ophiuroidea at subfamily level is presented based on a morphological data base of 43 characters. The tree is rooted using the best known fossil member of the stem-group. This identifies Ophiocanopidae as sister group to other extant ophiuroids, which themselves fall into two major groups, the Ophiurida and the Euryalida. Although our most parsimonious solution is highly resolved, not all parts of the cladogram are well supported. Molecular data from the 5' end of the large subunit ribosomal RNA molecule are presented for 10 taxa, with representatives from major higher groupings. This provides some support for the morphological tree, but leaves most of the deep branches unresolved. A phylogenetic tree is constructed for ophiuroids by selecting one of the cladograms as our working hypothesis and calibrating this against the stratigraphic record of the group. A revised taxonomy for the group is presented and the new taxon Ophiodermatina is erected.