STUDIES ON THE DEVELOPMENT OF PROCAMALLANUS (SPIROCAMALLANUS) REBECAE(NEMATODA, CAMALLANIDAE), A PARASITE OF CICHLID FISHES IN MEXICO

A description is given of the life cycle of the nematode Procamallanus (Spirocamallanus) rebecae (Andrade-Salas, Pineda-Lopez et Garcia-Maga na, 1994), an intestinal parasite of cichlids in Mexico. The copepod M esocyclops sp. was found to be a suitable experimental intermediate ho st. After the copepod's ingestion of free first-stage larvae of the ne matode, these enter the haemocoel of the intermediate host; they moult twice (on the 3rd and 5-6th day p.i. at 21-22 degrees C) before they attain the third, infective stage. The third-stage larva already posse sses the large buccal capsule without spiral thickenings and its tail tip bears three cuticular spines. The larvae undergo two additional mo ults (13-14 days and 42 days p.i.) in the definitive host (Cichlasoma urophthalmus) before changing to adults; the prepatent period is about 2-3 months. Experimental infection of guppies, Poecilia reticulata, h ave shown that these fishes may become paratenic (metaparatenic) hosts of this parasite. The morphology of individual larval stages of this nematode is described.