Two new species of Paraorygmatobothrium Ruhnke, 1994 (Cestoda: Tetraphyllidea) from the carcharhinid shark Carcharhinus cf. dussumieri (Müller & Henle) in the Persian Gulf.

New collections of tapeworms from the carcharhinid shark species Carcharhinus cf. dussumieri (Müller & Henle), the whitecheek shark, in the Persian Gulf have yielded two new species belonging to the tetraphyllidean genus Paraorygmatobothrium Ruhnke, 1994 (Phyllobothriidae). Both new species resemble the subset of Paraorygmatobothrium species that bear gongylate columnar spinitriches, rather than serrate gladiate spinitriches, on their distal bothridial surfaces. In combination, their shorter lengths, smaller number of testes and smaller bothridial apical suckers distinguish both Paraorygmatobothrium mobedii n. sp. and Paraorygmatobothrium sinuspersicense n. sp. from all but two of their congeners. They conspicuously differ from P. exiguum (Yamaguti, 1935), in that the spinitriches on their distal surfaces are not arranged on 'bumps' and from P. filiforme (Yamaguti, 1952) in their possession of fewer proglottids. The two new species differ from one another in cirrus-sac shape, testicular shape and arrangement, and vitelline follicle arrangement (i.e. 2 vs 4-6 follicles in each lateral band). In addition, statistically significant differences were seen in terminal proglottid length, ovarian length and apical sucker diameter. This brings the total number of species of Paraorygmatobothrium to 14, and extends the number of carcharhiniform host genera known to host members of the genus to seven. This is also the first description of tapeworms from an elasmobranch in the Persian Gulf.