Parapharyngiella caribbaea n. sp., a new species of Trigonostomidae (Rhabdocoela; Platyhelminthes) from Cuba, with a taxonomical reassessment of the genus

A new species of Parapharyngiella Willems, Artois, Vermin, Backeljau & Schockaert, 2005, Parapharyngiella caribbaea n. sp., is described from Cuba. It differs from Parapharyngiella involucrum Willems, Artois, Vermin, Backeljau & Schockaert, 2005, the only other species in this genus, by a much more posterior position of the pharynx, indicating that the anterior position of the pharynx is not a diagnostic character for the genus. It also differs in the sclerotized copulatory organ having a protuberance that is longer than the mantle. A morphological reassessment of the two known populations of P. involucrum (Zanzibar and Spain) reveals that these populations differ in many details, indicating that they belong to two different species. The population from Spain, therefore, is considered a separate species: Parapharyngiella steenkistei n. sp. Moreover, Proxenetes mackfirae Karling, 1978 is transferred to the genus Parapharyngiella.