ABSTRACT
The class Monogenoidea comprises a diverse group of platyhelminths parasitic primarily on the external surfaces and gills of marine and freshwater fishes. Phylogenetic relationships of the class have been under recent scrutiny, and this has resulted in many competing hypotheses regarding its position within the Neodermata, its monophyletic status, and interrelationships of included familial taxa. Boeger and Kritsky (1993) provided the first cladistic analysis of morphological features of members of the class (family level) and proposed a revised classification based on their results. The phylogenetic hypothesis of Boeger and Kritsky (1993) has been tested by addition of new familial taxa (Kritsky et al. 1993; Kritsky and Lim 1995) and morphological characters (Boeger and Kritsky 1997). These latter studies resulted in some alteration of phylogenetic support for clades, but did not significantly challenge the original hypothesis.
