North American freshwater ancyrocephalids (Monogenea) with articulating haptoral bars: phylogeny reconstruction

A phylogenetic (cladistic) analysis was conducted for 15 ancyrocephalid (Monogenea) species parasitizing North American freshwater fishes. The analysis was based on 10 (four binary and six multistate) characters. Vaginal characters were not included due to insufficient data. The resultant, most parsimonious cladogram was 38 steps long with a consistency index of 0.921: reduced consistency was attributed to two cases of homoplasy and one reversal. Three unresolved polychotomies were observed. Three clades were recognized: clade 1 — Actinocleidus species; clade 2 — Anchoradiscoides, Anchoradiscus, Clavunculus species and Syncleithrium; and clade 3 — Crinicleidus species. The protocol for and implications of character identification and polarisation and the establishment of transformation series were discussed.