Jainus iocensins, Cohen, Simone Chinicz, Kohn, Anna & Boeger, Walter A., 2012

Cohen, Simone Chinicz, Kohn, Anna & Boeger, Walter A., 2012, Neotropical Monogenoidea. 57. Nine new species of Dactylogyridae (Monogenoidea) from the gill of Salminus brasiliensis (Characidae, Characiformes) from the Paraná River, State of Paraná, Brazil, Zootaxa 3149, pp. 57-68 : 66

Jainus iocensins sp. n.

( Figs. 31–36)

Type locality. Paraná River below and above of the reservoir of Itaipu Hydroelectric Power Station in the locality of Foz do Iguaçú (25º32’52’’S, 54º35’17’’W) and Guaira (24º04’48’’S, 54º15’21’’W), State of Paraná, Brazil

Prevalence. 19.2% (5 of 26 fishes examined)

Specimens studied. Holotype, CHIOC 37647a; 38 paratypes, CHIOC 37606, 37635, 37637a–c–37638, 37640a–b, 37644–37646–37647b, 37650–37651, 37653, 37655, 37670, 37672a–c–37673a–b, 37675, 37687a–b, 37690, 37695a–c, 37700, 37702–37704, 37708, 37710a–b, 37712, 37723.

Etymology. The specific name alludes and honors the name of the Instituto Oswaldo Cruz (IOC) in recognition of its importance to the study of parasitology of sylvatic and domestic animals in Brazil and South America.

Description. (Based on 57 specimens). Body robust, pyriform, 330 (225–450; n=33) long, 139 (94–178; n=33) wide at midlength. Cephalic region with apical, two poorly developed cephalic lobes. Eyes 4, equidistant. Pharynx 19 (17–21; n=18) in diameter. Haptor with 7 pairs of hooks, with ancyrocephaline distribution. Ventral bar 19 (17– 20; n=8) long, broadly v–shaped with a posteromedian projection. Dorsal bar 31 (26–35; n=28) long, straight, rod– shaped. Ventral anchor 9 (7–12; n=55), with deep root, superficial root bearing irregular sclerotization, bladelike point and shaft, base width 9 (6–12; n=55). Dorsal anchor 33 (27–37; n=58) long, with poorly developed deep root, long superficial root, long, straight shaft with a hump-like thickening in the deep surface of the blade, sharply recurved point; base width 17 (15–20; n=58). Hooks 11 (8–15; n=42) long, with erected thumb, curved point, proximal enlargement of shank subcircular. FH loop about 0.6 shank length. MCO 21 (8–23; n=24) long, a thin sclerotized tube of one clockwise ring. Accessory piece 18 (15–21; n=24) long, hook-shaped, articulated to base of MCO by a copulatory ligament. Vagina sinistral. Vitellaria on two sides of trunk, absent in regions of reproductive organs. Egg ovate 53 (46–63; n=8) long, 41 (38–47; n=8), lacking polar filament.

Remarks. Besides the new species, four other species of Jainus are known: J. jainus Mizelle, Kritsky & Crane, 1968 from Chalceus macrolepidotus , J. robustus Mizelle, Kritsky & Crane, 1968 from Bryconops affinis (= Creatochanes affinis ), J. amazonensis Kritsky, Thatcher & Kayton, 1980 from Brycon melanopterus described from Brazil and J. hexops Kritsky & Leiby, 1972 from Astyanax fasciatus from Costa Rica. However, the morphology of anchors suggests that the new species most closely resembles J. amazonensis . It differs from this species by having a large sclerotization on the superficial root of ventral anchor and by the shape of the accessory piece, which is flabellate distally in J. amazonensis and hook-shaped in the new species.