PHYLOGENY OF LEECHES (HIRUDINEA) BASED ON MITOCHONDRIAL CYTOCHROME-C-OXIDASE SUBUNIT-I

The phylogenetic relationships of leeches were investigated for the fi rst time using molecular data. Twenty-one species were examined repres enting 7 of the 10 conventionally recognized euhirudinean families. In addition, Acanthobdella peledina, a branchiobdellid, four oligochaete s, and two polychaetes were included. Cladistic analysis of the mitoch ondrial cytochrome c oxidase subunit I gene yielded one most-parsimoni ous tree. Contemporary taxonomic groupings of leeches into higher cate gories were found to be largely consistent with monophyletic groups id entified in the analysis. Unusual relationships for which there is som e precedent include a sister-group relationship between the piscicolid s and Arhynchobdellida, as well as the grouping of the haemopids withi n Hirudinidae. (C) 1998 Academic Press.