A revision of Platybothrium Linton, 1890 (Tetraphyllidea: Onchobothriidae), with a phylogenetic analysis and comments on host-parasite associations.

摘要: A revision of Platybothrium Linton, 1890 is presented, based on available type and voucher material, as well extensive new collections from elasmobranchs belonging to the Carcharhinidae (requiem sharks) Sphyrnidae (hammerhead sharks). All 10 nominal species are treated or redescribed herein. Four these species, in addition one former member Dicranobothrium Euzet, 1953, considered valid members Platybothrium. Five described: P. angelbahiense n. sp. ex Carcharhinus leucas, coshtaprum C. plumbeus, jondoeorum Negaprion acutidens melanopterus, kirstenae obscurus, tantulum Sphyrna lewini S. zygaena. Sixty-three morphological characters were employed cladistic analyses nine five outgroup species. Coding analysis strategies varied assess effects coding inapplicable missing a separate character state, excluding for which data more than 10% taxa. The coded state no excluded produced best-supported most conservative estimate interrelationships spp. appears be monophyletic assemblage, with basal being spinulifera Southwell, 1912. group possessing an accessory piece between hooks forms clade within genus. Species lacking piece, had previously been placed do not appear each other's closest relatives; thus, synonym An examination host associations indicated that broadly distributed among, entirely restricted to, carcharhinid sphyrnid shark Most exhibit oioxenous host-specificity, all but two parasitising only single In several multiple congeners parasitise same individual, phenomenon reported