Phylogenetic relationships of the Dactylogyridae Bychowsky, 1933 (Monogenea: Dactylogyridea): the need for the systematic revision of the Ancyrocephalinae Bychowsky, 1937.

Phylogenetic analyses based on partial 18S rDNA sequences of polyonchoinean monogeneans were conducted in order to investigate the relationships between selected families and subfamilies of the Dactylogyrinea, mainly within the Dactylogyridae. We tested the status of the Ancyrocephalidae sensu Bychowsky & Nagibina (1978) and the Ancyrocephalinae sensu Kritsky & Boeger (1989). Within the Dactylogyrinea, the Diplectanidae and Dactylogyridae are well supported by maximum likelihood and maximum parsimony analyses, but their phylogenetic relationship with the Pseudomurraytrematidae remains unresolved. Phylogenetic relationships between the Pseudodactylogyrinae, Ancyrocephalinae, Ancylodiscoidinae and Dactylogyrinae indicate paraphyly of the Ancyrocephalidae sensu Bychowsky & Nagibina (1978). The group of species recently considered as the Dactylogyridae sensu Kritsky & Boeger (1989) comprises two sister groups. The first group includes the freshwater Ancyrocephalinae and the Ancylodiscoidinae. The second group includes the Pseudodactylogyrinae, Dactylogyrinae and the Ancyrocephalinae from the fish species Siganus doliatus and Tetraodon fluviatilis. The non-monophyly of the Ancyrocephalinae (i.e. the non-monophyly of the group of species recently considered as members of Ancyrocephalinae), previously suggested by Kritsky & Boeger (1989) using the morphological characters, indicates that classification of the Dactylogyridae needs to be revised.