Paraorygmatobothrium barberi n. g., n. sp. (Cestoda: Tetraphyllidea), with amended descriptions of two species transferred to the genus

Abstract

Paraorygmatobothrium n.g. (Cestoda: Tetraphyllidea) differs from all other phyllobothriid genera in having serrated microtriches on the proximal bothridial surfaces, two dorsal and two ventral scutes on the neck, and the presence of very small (<500 nm) triangular structures on the surface of the neck. No single light microscopical feature is sufficient to distinguish the new genus from other phyllobothriid genera. Phyllobothrium prionacis from Prionace glauca and Anthobothrium exiguum from Alopias vulpinus are transferred to the new genus and their descriptions are amended. Paraorygmatobothrium barberi n. sp. from Triakis semifasciata is also described, and can be distinguished from the other two species in being longer, having a greater number of segments, longer and wider mature segments, a greater number of testes, a longer cirrus-sac, a longer and wider ovary, a wider ovicapt, and a greater number of rows of dorsal and ventral vitelline follicles than the other two species. It also differs in the shape of the egg-shell and in the possession of a circular band of sub-tegumentary muscles in the middle third of each bothridium. Two of the species placed in the new genus have microtriches resembling an "ear of corn" on the distal bothridial surface. These microtriches are similar to structures reported for Phyllobothrium squali from the Squalus acanthias and Orygmatobothrium musteli from Mustelus henlei; this similarity in microtriche structure potentially indicates a systematic relationship between members of Paraorygmatobothrium and these two species. © 1994 Kluwer Academic Publishers.