Anacanthorus contortus, 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 : 60

Anacanthorus contortus sp. n.

( Figs. 3–4 )

Type locality. Paraná River below and above of the reservoir of Itaipu Hydroelectric Power Station in the locality of Guaira (24º04’48’’S, 54º15’21’’W), State of Paraná, Brazil

Prevalence. 30.7% (8 of 26 fishes examined)

Specimens studied. Holotype, CHIOC 37662a; 30 paratypes, CHIOC 37583, 37601a–c, 37605, 37615, 37620a–b, 37621a–b, 37626, 37632, 37660a–c, 37662b, 37705–37707, 37714, 37716, 37718a–b–37721, 37724, 37727a–b, 37729.

Etymology. The specific name is from latin ( contortus = whirling) and refers to the intricate organization of the accessory piece.

Description. (Based on 47 specimens). Body 801 (460–1,020; n=14) long, 246 (165–345; n=14) wide. Tegument smooth. Cephalic lobes 3, well developed, each with head organs. Eyes 4, posterior pair larger than anterior; accessory granules scattered in cephalic region. Pharynx 54 (40–64; n=17) long, 46 (38–60; n=17) wide. Haptor with 7 pairs of hooks, anacanthorine distribution. Anchors, bars absent. Hooks 19 (16–22; n=82) long, with depressed thumb, curved shaft, short recurved point, shank proximally expanded; FH loop about ½ shank length. MCO 106 (92–115; n=38) long, a wide sigmoid tube, with complex prominent flare distal end; base with heavily sclerotized borders, opening lateral to longitudinal axis of MCO. Accessory piece 79 (67–87; n=38) long, articulated to base of MCO, rod-like, with two main branches; one long, straight, distally tapering; another composed of 4 sub-branches, two short medial, two long distal. Testis 80 long, 56 wide (n=1), postgermarial; seminal vesicle a dilation of vas deferens; vas deferens looping left intestinal cecum. Germarium 62 (44–75; n=3) long, 92 (80–110; n=3), irregular, pretesticular. Vitellaria in two bilateral fields of trunk, from pharynx to the posterior region of trunk, coextensive with intestinal ceca. Oviduct, ootype not observed. Eggs 38–61 long, 40–63 wide (n=3), spherical, bearing short filament. Metraterm delicate.

Remarks. Anacanthorus contortus sp. n. is apparently a member of a group of Anacanthorus species parasitizing Triportheus spp., including, A. chaunophallus Kritsky, Boeger & Van Every, 1992 , A. cornutus Kritsky, Boeger & Van Every, 1992 , A. formosus Kritsky, Boeger & Van Every, 1992 , A. euryphallus Kritsky, Boeger & Van Every, 1992 , A. furculus Kritsky, Boeger & Van Every, 1992 , A. glyptophallus Kritsky, Boeger & Van Every, 1992 , A. lygophallus Kritsky, Boeger & Van Every, 1992 , A. nanus Kritsky, Boeger & Van Every, 1992 , A. pelorophallus Kritsky, Boeger & Van Every, 1992 , A. pithophallus Kritsky, Boeger & Van Every, 1992 , A. quinqueramus Kritsky, Boeger & Van Every, 1992 and A. ramulosus Kritsky, Boeger & Van Every, 1992 . All of these species depict a wide MCO tube and a branched and articulated accessory piece. The new species resembles A. quinqueramus Kritsky, Boeger & Van Every, 1992 from Triportheus albus Cope , Triportheus elongatus (Guenther) and Triportheus sp. from Amazon River Basin, in depicting an accessory piece composed by five branches. However, in this previously described species, these branches are significantly shorter and their arrangement is conspicuously distinct from that of A. contortus sp. n. While the new species has an accessory piece composed by two main branches, one of them branching into 4 sub-branches, A. quinqueramus depicts a long ramus connected to one short and two long rami, one of which depict a short subterminal branch

Figures

FIGURES 1 – 10. Sclerotized parts of Anacanthorus spp. from the dourado, Salminus brasiliensis, from Paraná River, Brazil. Figs. 1 – 2. Anacanthorus bicuspidatus 1. Copulatory complex (dorsal view). 2. Hook. Figs. 3 – 4. Anacanthorus contortus sp. n 3. Copulatory complex (dorsal view). 4. Hook. Figs. 5 – 6. Anacanthorus daulometrus sp. n. 5. Copulatory complex (ventral view). 6. Hook. Figs. 7 – 8. Anacanthorus douradensis sp. n.. 7. Copulatory complex (dorsal view). 8. Hook. Figs. 9 – 10. Anacanthorus kruidenieri sp. n. 9. Copulatory complex (dorsal view). 10. Hook. Fig. 7 is presented to the 50 µm scale; Figs. 2, 4, 6, 8 and 10 to the 10 µm scale; Figs. 1, 3, 5 and 9 to the 30 µm scale.