[Sensillae of cercariae of Haplorchis taichui (Digenea, Heterophyidae). Discussion of the systematics of the Opisthorchioidea].

Cercarial chaetotaxy of Haplorchis taichui (Haplorchiinae, Heterophyidae) is described and compared to that of ten other Opisthorchioidea: three belonging to the Acanthostomidae (Acanthostominae), one to the Opisthorchiidae (Opisthorchiinae) and six to the Heterophyidae (among these, two Centrocestinae, two Apophallinae, one Euryhelminthinae and one Haplorchiinae). Cercarial chaetotaxy allow us to distinguish the considered species and genera, but does not support division of the Opisthorchioidea into families as these have been defined based on morphology of adults; it suggests that the Heterophyidae is heterogenous; it allows us to recognize the Opisthorchioidea characterized by a loss of hexaradial symmetry on the first cephalic cycle of sensillae and by the presence of two to five pairs of sensillae on a tail with proximal excretory apertures.