Preliminary comments on a phylogenetic study of the order Diphyllidea van Beneden in Carus, 1863

摘要

The basis for a preliminary analysis of the relationships within the monophyletic Diphyllidea is outlined. Information on morphological characters and their interpretation within a phylogenetic context are presented. A cladistic analysis at specieslevel was conducted based on a matrix of 21 morphological characters. Character polarity was determined by taxonomic outgroup analysis relative to the basal orders, Pseudophyllidea and Haplobothriidea. The phylogeny for Diphyllidea was poorly resolved, based on currently available characters. Computer assisted cladistic analysis found 3 equally parsimonious trees with a consistency index of 0.54. The topology of these trees shows that Ditrachybothridium macrocephalum is the basal taxon and the putativesister group for species of Echinobothrium; Macrobothridium rhynchobati is grouped among species of Echinobothrium. If the classification is to be consistent with this tree, M. rhynchobati should be included in the genus Echinobothrium.