Examination of seven specimens of an undescribed species of bamboo shark (Orectolobiformes: Hemiscylliidae), currently referred to as Chiloscyllium sp. 1, from Sri Lanka yielded three new species of 'tetraphyllidean' cestodes, one each in the genera Carpobothrium Shipley et Hornell, 1906, Spiniloculus Southwell, 1925, and Yorkeria Southwell, 1927. Carpobothrium marjorieae Caira, Otto et Jensen sp. n. differs from its three valid congeners in total length, number of testes, and size of the apical sucker of its anterior bothridial flap. Like Carpobothrium eleanorae Koontz et Caira, 2016 it possesses spherical eggs with highly elongate bipolar filaments, but its eggs are conspicuously larger than those of the latter species. Spiniloculus akshayi Caira, Otto et Jensen sp. n. can be distinguished from its five congeners in total length and number of proglottids. Yorkeria sachiniae Caira, Otto et Jensen sp. n. differs from its 16 congeners in number of proglottids and testes, total length, terminal proglottid, cirrus sac, and cephalic peduncle length, hook size, genital pore position, and bothridial shape. The eggs of Y. sachiniae Caira, Otto et Jensen sp. n. are spindle-shaped and bear a single long, polar filament. All three species were found to exhibit microthrix patterns on their scolices like those of the majority of their congeners that have been examined to date with scanning electron microscopy. Microtriches on the distal surfaces of the bothridial pouches of a species of Carpobothrium were characterised for the first time; C. marjorieae Caira, Otto et Jensen sp. n. was found to possess a modified form of gladiate spinithrix on this surface. Among the seven members of the genus, this is the first species of Chiloscyllium Müller et Henle that has been found to host representatives of all three of these 'tetraphyllidean' genera. However, unlike most of its congeners, a representative of the non-hooked genus Scyphophyllidium Woodland, 1927 was not found infecting Chiloscyllium sp. 1.
The type species (Spiniloculus mavensis Southwell, 1925) of the previously monotypic tetraphyllidean genus Spiniloculus Southwell, 1925 is redescribed from the type material from Moreton Bay, Australia. As a consequence the identity of this species is definitively resolved. Three new species in the genus, all collected from Chiloscyllium punctatum Müller et Henle (brownbanded bambooshark), in Borneo, are described. Spiniloculus calhouni sp. n. conspicuously differs from all three of its congeners in its possession of post-poral testes. Spiniloculus fylerae sp. n. and Spiniloculus paigeae sp. n. differ from their two other congeners in that they are relatively small worms (4-6.5 and 2.2-5 mm in total length, respectively) with fewer than 30 proglottids. They can be distinguished from one another in that, while the vitelline follicles are interrupted at the level of its ovary in S. fylerae, this is not the case in S. paigeae. Furthermore, whereas the cirrus sac of the former species is pyriform, it is elongate-oval in the latter species. This brings the total number of species in the genus to four, and lends support to the suggestion that the original identity of the type host of S. mavensis as Mustelus sp. was in error. This work also extends the range of the genus to include the island of Borneo. A key to the species of Spiniloculus is provided. Morphological data generated here, using both light and scanning electron microscopy, support the suggested close affinities between Spiniloculus and Yorkeria Southwell, 1927, both of which parasitize bamboosharks.