Review of the Rhopalothylacidae Guiart, 1935 (Cestoda: Trypanorhyncha), with a description of the adult of Pintneriella musculicola Yamaguti, 1934 and a redescription of P. gymnorhynchoides (Guiart, 1935) comb. n.

The family Rhopalothylacidae (Cestoda: Trypanorhyncha) is reviewed. The type species, Rhopalothylax gymnorhynchoides Guiart, 1935, is redescribed from the type specimens and belongs within the genus Pintneriella Yamaguti, 1934, previously described only from the plerocercus. Rhopalothylax therefore becomes a junior synonym of Pintneriella. The adult of Pintneriella musculicola Yamaguti, 1934 is described for the first time, from the shark Carcharias taurus Rafinesque from Australia. Pintneriella is characterised by two bothridia, a typical heteroacanthous armature, a unique, bipartite external seminal vesicle and a uterus deviated porally, terminating at a uterine pore. It belongs within the Heteracanthoidea but is distinguishable both from the Eutetrarhynchidae and the Gilquiniidae, the two families which it most closely resembles. Cladistic analyses align Pintneriella within the clade containing the families Gilquiniidae, Gymnorhynchidae and Molicolidae rather than with the Eutetrarhynchidae. The family Rhopalothylacidae is therefore retained provisionally to accommodate Pintneriella within the Heteracanthoidea. The second genus of the Rhopalothylacidae, Clujia Guiart, 1935, is unrecognisable from its description and cannot be redescribed from its holotype. It is therefore considered a genus inquirendum.