Two new species of Pseudochristianella Campbell & Beveridge, 1990 (Cestoda&COLFAML; Trypanorhyncha) from Elasmobranch fishes from the Gulf of California, Mexico

Pseudcchristianello elegontissima so, nov. Cestoda: Trypanorhyncha is described from the spiral valves of the rays Dasyatis brevis Garman, 1880) and D. longus Garman, 1880), from the Gulf of California, Mexico. Also described is P. nudiscula sp. nov. from rays Rhinobatos productus Ayres, 1854, D. longus, Myliobatis longirostris Applegate & Fitch, 1964 and Zopteryx exasperato (Jordan & Gilbert, 1880) from the some location. The species ore distinguished from one another and from the only existing species within the genus, P. southweilli Campbell & Beveridge, 1990, by differences in the arrangement of bill-hooks on the external surface of the basal swelling of the tentacle and by the number of hooks in each row of the metabasasl armature.