Dionchus postoncomiracidia (Monogenea : Dionchidae) from the skin of blacktip sharks, Carcharhinus limbatus (Carcharhinidae)

Postoncomiracidia of Dionchus sp, are described from specimens collected fr om the skin of 2 blacktip sharks Carcharhinus limbatus, captured in the nor thern Gulf of Mexico. The parasites resemble nonciliated oncomiracidia hatc hed from eggs laid by Dionchus sp, on gills of a cobia Rachycentron canadum and adults of Dionchus remorae that were collected from gills of a common sharksucker Echeneis naucrates, captured in association with a third blackt ip shark. The hamuli of the postoncomiracidia were morphologically similar to those of adult D. remorae. This is the first report of dionchids from an elasmobranch and from a location other than the gills. These findings supp ort the idea that some dionchid oncomiracidia colonize the skin of sharks o r other aquatic vertebrates that sponsor remoras, prior to transferring to other remoras and maturing.