Drawings of Martorellius valenciennesi comb. n. (USNM 1382361) parasite of Parapimelodus valenciennis from de La Plata River, Buenos Aires, Argentina. A – copulatory complex in ventral view – MCO: accessory piece (AP); base of the MCO (BMCO). B – vagina: vagina canal (VC), fringes of vaginal atrium (FR). C – composite drawing of the dorsal bar. D – ventral bar. E – hook 1. F – hook 2. G – hook 7. H – ventral anchor. I – dorsal anchor. Scale bar = 15 µm.