The trypanorhynch cestode family Pterobothriidae Pintner, 1931 is revised. Valid species of the genus Pterobothrium Diesing, 1850 are defined. Ten species of pterobothriid cestodes, including five new species, are described from elasmobranchs taken in waters off Australia, the Indian Ocean, the Atlantic coast of North America, and in the S Atlantic off Senegal, West Africa. Six of the species, P. acanthotruncatum, P. lintoni, P. lesteri, sp. nov., P. pearsoni, P. southwelli, sp. nov., and P. australiense, sp. nov., are described from fishes in Australian waters and the Indian Ocean. The armature of Pterobothrium heteracanthum Diesing, 1850 is redescribed using light and scanning electron microscopy. New intermediate hosts, locality records, and synonyms are provided for P. crassicolle Diesing, 1850 from Atlantic coastal waters of North and South America. Details of the entire armature of Pterobothriurn crassicolle Diesing, 1850 from Micropogonias furnieri (Desmarest) from Rio de Janiero are included. Two new species of Pterobothrium, P. kingstoni, sp. nov., and P. senegalense, sp. nov., are described from dasyatid rays in waters of the Atlantic Ocean. P. kingstoni, sp. nov., from dasyatid rays taken in coastal waters off New England and Chesapeake Bay, Virginia, is distinguished by the presence of a wide band of hooks on the external face of the tentacle, a single row of 4 intercalary hooks, absence of a basal swelling and special armature and by a transverse base on hooks 4(4′) of each principal metabasal row. Pterobothrium senegalense, sp. nov., is described from Dasyatis centroura from Gorbe, Senegal, West Africa, and is distinguished by 3 intercalary rows of hooks that run over onto the external tentacular face but never occupy the midline, by the size and position of hooks in the first intercalary row, and position of the first intercalary row relative to the second and third rows. Pterobothrium southwelli, sp. nov., P. lesteri, sp. nov., and P. pearsoni are described from teleosts in the Indian Ocean. P. southwelli, sp. nov., is distinguished from congeners by a distinctive basal armature and prominent band of hooks on the external surface, a single intercalary row, uncinate hooks l(1′) in all metabasal principal rows, and absence of dentate hooks from the metabasal rows. P. lesteri, sp. nov., is unique in the combination of a basal row of 3 small hooks, a band of hooks, a single intercalary row of 3–4 hooks and in the possession of hooks 4(4′) with dentate tips and hooks 5(5′) with filamentous tips. P. pearsoni differs in possessing a band of hooks and 2 rows of intercalary hooks per principal row, basal armature restricted to the external surface, and uncinate hooks l(1′) combined with dentate hooks 4(4′)–5(5′) in all metabasal rows.
Three species from Australian waters, P. lintoni (MacCallum, 1916), P. australiense, sp. nov., and P. acanthotruncatum, lack a well-developed band of hooks on the external face of the metabasal armature. P. lintoni (MacCallum, 1916), the senior synonymn of P. malleum MacCallum, 1916) and P. dasybati Yamaguti, 1934, is described from types and compared with new specimens from the Woods Hole region (USA) and Australia. New host records for adults and plerocerci of P. lintoni are reported from Australian waters off Queensland and South Australia. Pterobothrium chaeturichthydis (Yamaguti, 1952) is considered a synonym of P. lintoni. P. australiense, sp. nov., from Pristis zijsron near Townville, Queensland, differs from congeners in the possession of slender falcate hooks 1(1′), notched tips of hooks 5(5′), a single intercalary row of 3 hooks, and total absence of a band of hooks on the external tentacular face. P. australiense, sp. nov., is similar to P. acanthotruncatum but has falcate hooks at the start of each principal row, lacks the pairs of satellite microhooks on the external face adjacent to the principal rows and possesses a band of microhooks in the basal region of the external face of the tentacle. P. acanthotruncatum is reported from new hosts in Australia and from Sri Lanka and India.
A key to the 12 currently recognised species of pterobothriids is provided.
