The oncomiracidium of Nasicola klawei (Monogenea: Capasalidae: Capsalinae).

The oncomiracidium of the capsaline Nasicola klawei (Monogenea: Capsalidae), adults of which were collected from the nares of the yellowfin tuna Thunnus albacares (Scombridae) caught off Nelson Bay on the east coast of Australia, is described. This is a new locality record for N. klawei. This is the first description of an oncomiracidium of a Nasicola species and only the third time the larva of a capsaline species has been documented. The oncomiracidium of N. klawei is distinguished from others in the subfamily by the distribution of the body pigment and large distinct refringent (lipid?) droplets in the body and the prominent, posteriorly directed pointed process on the guard of each of the 14 hooklets. Oncomiracidia of the other two described Nasicola species, N. hogansi and N. brasiliensis, should be examined to determine whether these characters have generic or species-specific significance.