Curvianchoratus dominguesi Bezerra, Cohen, Meneses & Justo, 2023

Bezerra, Carine Almeida Miranda, Cohen, Simone Chinicz, de Meneses, Yuri Costa, Neres, Helyab Gabriel Chaves, Viana, Diego Carvalho & Justo, Marcia Cristina Nascimento, 2023, Two new species of Curvianchoratus (Monogenoidea, Dactylogyridae) parasitizing Psectrogaster amazonica (Characiformes, Curimatidae) and a new record for Curvianchoratus singularis in the Tocantins River, Maranhao, Brazil, ZooKeys 1172, pp. 101-116 : 101

Curvianchoratus dominguesi Bezerra, Cohen, Meneses & Justo sp. nov.

Figs 4A-G , 5C, D, F

Type host.

Psectrogaster amazonica Eigenmann & Eigenmann, 1889 ( Curimatidae ).

Type locality.

Embiral, rural zone (5°27'50"S, 47°33'48"W), municipality of Imperatriz, Maranhão State.

Infestation parameters.

5.15% prevalence; 8 total number of parasites; 1.14 ± 0.26 mean intensity; 1-2 range of intensity.

Deposited material.

Holotype: CHIOC 39984; paratypes: CHIOC 39985, 39986, 39987, 39988, 39989.

Etymology.

The specific name is in honor of Dr Marcus Vinicius Domingues for his contributions to the knowledge of neotropical monogenoidean fauna.

Description.

Based on 7 specimens: 1 mounted in Gomori’s trichrome and 6 mounted in Hoyer’s medium: Body short, broad, 460-750 (575; N = 6) long, 225-500 (362; N = 6) wide. Tegument smooth. Cephalic region with 3 pairs of lateral lobes (two lateral and one terminal); five pairs of head organs; cephalic glands lateral to pharynx. Eyespots absent. Pharynx muscular, 50-63 (55; N = 3) long, 48-69 (58; N = 3) wide, esophagus short. Haptor small, compared to body size length, 400 (N = 2) wide. Ventral bar short and robust, anvil-shaped, with slightly jagged edges, 50-58 (52; N = 4) long. Ventral anchor with inconspicuous roots, shaft with two subunits, 25-32 (30; N = 5) long, with a short base, 11-17 (14; N = 5). Dorsal anchor complex heavily modified composed by 2 subunits: dorsal-median and dorsal. Dorsal-median subunit robust curved and heavily sclerotized, 50-66 (58; N = 13) long, shaft, 41-47 (44; N = 14); point as a robust hooked thorn, 6-10 (8; N = 14); superficial root, 5-8 (7; N = 3) and deep root, 13-17 (15; N = 6), well developed with borders very close to each other; point, 6-10 (8; N = 14). Dorsal subunit elongated, 65-100 (77; N = 9) long and 18-23 (19; N = 9) wide, 30% larger than the dorsal-median subunit, posterior portion fan-shaped. Hooks similar in shape, with erected thumb, curved shaft, and dilated bulb in the end, pair 1 smaller than the others, 11-12 (11; N = 4) long; pairs 2-7, 14-17 (16; N = 37). Copulatory complex comprising male copulatory organ and articulated accessory piece. MCO tubular, sclerotized, makes a short coil on itself, near the cirrus base, 55-75 (69; N = 4) in total length. Accessory piece claw-shaped, bifurcated, with different tip sizes; the smaller serves as a guide for the MCO, 42-70 (56; N = 5) long. Testis oval dorsal to the germarium; seminal vesicle formed by a distal enlargement of the vas deferens; prostatic reservoir single, in form of half-moon. Germarium pretesticular; seminal receptacle anterior to germarium; vaginal opening sinistro-ventral; vaginal canal wall sclerotized; oviduct, ootype, uterus, and eggs not observed. Vitellaria dense extends over the entire body, except in the region of the reproductive organs and haptor.

Remarks.

Curvianchoratus dominguesi sp. nov. is similar to the other species of the genus mainly by the morphology of the dorsal anchor, the copulatory complex, which is composed by a long cirrus and a pincer-shaped accessory piece, connected to the base of the cirrus. The new species is similar to C. singularis and C. hexacleidus by the presence of the ventral bar. The new species differs from all congeneric species by the shape of the ventral anchor (formed by a shaft with two subunits in the new species vs. well-developed roots in C. hexacleidus and moderately developed deep root and well-developed superficial root in C. singularis and C. psectrogasteri sp. nov.), the morphology of the ventral bar (short and robust, anvil-shaped ventral bar in C. dominguesi sp. nov. vs. serpentine-shaped in C. hexacleidus , M-shaped in C. singularis and absent in C. psectrogasteri sp. nov.) and by the ratio of the subunits of the dorsal anchor (dorsal subunit is 30% larger than the dorsal-median subunit in C. dominguesi sp. nov. vs. the approximately same size of the subunits in the other three species of the genus).

Figures

Figure 4. Curvianchoratus dominguesi n. sp from Psectrogaster amazonica from Tocantins River A whole specimen, ventral view B copulatory complex, ventral view C ventral bar D hook E ventral anchor F dorsal-median subunit G dorsal subunit. Scale bars: 100 μm (A); 30 μm (B, F, G); 10 μm (C - E).

Figure 5. Light photomicrographs of Curvianchoratus spp. A, B, E Curvianchoratus psectrogasteri sp. nov. A total, ventral view B copulatory complex, ventral view E haptor C, D, F Curvianchoratus dominguesi sp. nov. C copulatory complex, ventral view D total, ventral view F haptor. Scale bars: 100 μm (A); 20 μm (B); 30 μm (C, F); 100 μm (D); 40 μm (E).