Dr. Murai Éva szerk.: Parasitologia Hungarica 21. (Budapest, 1988)

The taxon including gastrothylacid flukes has been regarded to be of family rank due to the occurrence of the special evolutionary novelties (ventral pouch and pharynx without appendages and habitat). Their ancient character state is the position of the excretory pore. The latter trait provides connection towards the Zygocotylidae and the former ones bridge it with Paramphistomidae. The taxon Paramphistomidae is the youngest group of amphistomes from the phylogenetic point of view. It divides into two equal ranks of taxa (subfamilies: Orthocoeliinae and Paramphistominae), the former with a plesiomorphic feature (position of excretory pore) and with several other apomorphic character states. Paramphistominae comprises the most apomorphic group of amphistomes. Beside the series of apomorphic characters, plesiomorph traits can be found in the circular musculature (sphincter) of the pharynx. Zygocotylidae Paramphistomidae r i i 1 Fig. 3. Phylogenetic relationships among families and subfamilies of Paramphistomoidea