PRELIMINARY PHYLOGENETIC ANALYSIS OF SUBFAMILIES OF THE PROTEOCEPHALIDEA (EUCESTODA)

Cladistic analysis based on comparative morphology was used to examine the subfamily-level relationships within the cestode order Proteoceph alidea. A single most parsimonious tree (70 steps, CI = 0.571; RC = 0. 295; HI = 0.471) is consistent with monophyly for the Proteocephalidea and showed a relatively high consistency at the family level with the diagnosis of two major subclades. Unambiguous support for a Proteocep halidae subclade, including the Corallobothriinae, Proteocephalinae, G angesiinae and Sandonellinae, and a Monticelliidae subclade, including the Marsypocephalinae, Zygobothriinae, Monticelliinae, Rudolphiellina e, Ephedrocephalinae and Othinoscolecinae was evident. Two subfamilies , the Acanthotaeniinae (historically in the Proteocephalidae) and Nupe liinae (historically in the Monticelliidae), were however, basal to al l other subfamilies, indicating that neither family as currently conce ived is monophyletic. Trees one or two steps longer, however, would be consistent with monophyly for the Proteocephalidae and Monticelliidae (excluding Acanthotaeniinae) or would result in the monophyly for bot h families, including all respective subfamilies congruent with curren t concepts for systematics of the order. Zoogeographical analysis demo nstrated a strong Gondwanan association; proteocephalideans originated in Africa, with subsequent development linking Africa and South Ameri ca. Colonisation of the Northern Hemisphere by proteocephalid subfamil ies, the Proteocephalinae, Corallobothriinae and Gangesiinae, was seco ndary. Analysis of parasite-host relationships indicated that the basa l hosts for the Proteocephalidea are equivocal; siluriform teleosts we re, however, the basal hosts for the Nupeliinae + the Monticeiliidae a nd Proteocephalidae subclades and an extensive co-evolutionary history with this host group is postulated. Independent colonisation events o f reptilians by species of the Proteocephalinae and Acanthotaeniinae, non-siluriform teleosts associated with the Sandonellinae and some Pro teocephalinae, and amphibians by some Proteocephalinae, are recognised . Some points which should be considered for further development of th e systematics of the group are proposed, with special emphasis given t o thorough morphological descriptions and investigations of Life-cycle s.