Abstract:Two new species of entobdelline (capsalid) monogeneans are described from the skin of Australian dasyatid stingrays, namely Neoentobdella cribbi sp. n., a small parasite from the estuarine stingray, Dasyatis fl uviorum Ogilby (Elasmobranchii: Dasyatidae) and Neoentobdella baggioi sp. n., a relatively large parasite from the porcupine ray, Urogymnus asperrimus (Bloch et Schneider) (Elasmobranchii: Dasyatidae). A striking feature of both of these new parasite species is a pad, possibly located within the genital atrium, armed with rows of closely spaced, rod-shaped microsclerites. Both species also possess a muscular papilla in the genital tract and a club-shaped structure near the common genital opening on the left lateral margin of the body. In N. cribbi, the latter feature is large and located anterior to the genital pad and in N. baggioi, it is small and located in a more posterior position. Similar embellishments in the genital area occur in N. natans Kearn et Whittington, 2005 Neoentobdella spp. are entobdelline (capsalid) monogeneans living on the skin of stingrays (Elasmobranchii). While examining freshly caught estuary stingrays, Dasyatis fl uviorum Ogilby (Dasyatidae) off Stradbroke Island, Queensland, Australia, Dr. Tom Cribb (University of Queensland) found several entobdelline monogeneans on the ventral surfaces and kindly donated these specimens to us. Entobdelline monogeneans were also collected from another dasyatid, namely the porcupine ray, Urogymnus asperrimus (Bloch et Schneider) (Dasyatidae), collected on Sudbury Reef, an inshore reef south-east of Cairns, Queensland, Australia by staff of Cairns Marine Aquarium Fish, Cairns. These parasites were collected by Mr. Julian Baggio (Senior Aquarist at this facility) and sent to us for study. A preliminary examination revealed novel anatomical features indicating that the parasites had not previously been described and prompted us to study their anatomy in detail.
MATERIALS AND METHODSParasites preserved in 10% formalin were later stained with Semichon's carmine or left unstained. The specimens were dehydrated in an ethanol series, cleared in cedarwood oil and mounted in Canada balsam. Whole mounts were studied using a compound microscope equipped with phase contrast optics. Measurements, made using a calibrated ocular micrometer, were restricted to unfolded, fl attened specimens, are presented in micrometres as the mean followed by the range in parentheses and the number of measurements taken. Where measurements are presented in paired sets separated by a multiplication sign, the fi rst is length and the second is width. Haptoral terminology for capsalids follows Whittington et al. (2001).