Light photomicrographs of Ameloblastella sakulocirra n. sp., a parasite of Phractocephalus hemioliopterus, from the Tapajós river basin, Pará, Brazil. A and B – copulatory complex: male copulatory organ (MCO), base of the MCO (BMCO), ligament of the accessory piece (LAP) to the base of the MCO, and the sac that surrounds the MCO (SMCO). C – ventral bar and anchor. D – dorsal bar and anchor. Scale bar = 15 µm.