A TOTAL EVIDENCE APPROACH TO THE PHYLOGENY OF SOME NEREIDIFORMIA (POLYCHAETA)
Dahlgren, T. 1; Lundberg, J.2; Pleijel, F. 2, 3 & Sundberg, P.1
1Goteborg University, Department of Zoology, P.O. Box 463, SE-405 30 Goteborg, Sweden
2Tjärnö Marine Biological Laboratory, Pl. 2781, S-452 96 Strömstad, Sweden
3Swedish Museum of Natural History, Box 50007, S-104 05 Stockholm, Sweden
The monophyletic status of the nereidiform polychaete taxa Chrysopetalidae and Hesionidae has previously been challenged. The mitochondrial cytochrome oxidase I gene (COI) was used to investigate nereidiform phylogeny. A 660 bp segment of the COI was sequenced for two chrysopetalids, one nereidid, one pilargid, one pisionid, and four hesionids (of which two of the latter are of uncertain family affinity; Hesionides, Microphthalmus). A parsimony analysis of the new molecular data combined with 46 absent/present coded morphological characters yielded a single most parsimonious tree. This analysis, based on 318 informative characters, give further support to the results from the morphological character set alone and indicate that chrysopetalids and hesionids are well delineated, that pilargids and hesionids are non-overlapping, and that Microphthalmus and Hesionides are not hesionids.