Class Monogenoidea Bychowsky, 1937
Subclass Polyonchoinea Bychowsky, 1937
Order Dactylogyridea Bychowsky, 1937
Dactylogyridae Bychowsky, 1933
Cosmetocleithrum Kritsky, Thatcher & Boeger, 1986
Cosmetocleithrum infinitus n. sp. (Figs. 1-9)
Type host: Anadoras grypus (Siluriformes: Doradidae),
Type locality: Amazon river, Iquitos, Peru, July 2019 (04°14´55.4” S, 068°45´12.2” W).
Site of infection: Gill filaments.
Specimens deposited: Holotype, MUSM XXX; 4 paratypes, MUSM XXX
Etimology: The specific name comes from the latin infinitus = infinitum, and refers to the form of the MCO that presents uncountable rings.
Description (based on 05 specimens – 01 stained, 04 cleared) (Figs. 1-9).
Body large and elongated, 731–817 (772; n = 05) long, greatest width 173–22 (189; n = 05), cephalic lobes poorly developed. Four pairs of head organs. Eyes inconspicuous. Pharynx muscular, subspherical, 28–33 (30; n = 05) wide; esophagus short, intestinal caeca two, confluent posteriorly, lacking diverticula. Peduncle short, narrow; haptor, globose, 42–79 (56; n = 05) long, 78–132 (94; n = 05) wide. Ventral anchor 14–20 (16; n = 05) long, 10–15 (12; n = 05) wide, with well differentiated roots, superficial root much longer than deep root, straight shaft and point. Dorsal anchor 15–19 (17; n = 05) long, 11–14 (12; n = 05), with inconspicuous roots. Anchor with slightly curved shaft and point. Ventral bar, 38–73 (54; n = 05) long, 10–12 (12; n = 05) wide, V-shaped. Dorsal bar 33–52 (47; n = 05) long, 2–4 (3; n = 05) wide, slightly U-shaped with two submedial short projections directed posteriorly. Hooks 10–14 (12; n = 20) long, with dactylogyridae distribution, similar in shape, with erect thumb, straight shaft and point; shank tapering proximally. Testis postgermarial, elongated, germarium ovate, anterior to testis; vas deferens looping left of intestinal cecum; seminal vesicle elongate; elongated prostatic reservoir. Copulatory complex comprising male copulatory organ (MCO) and accessory piece. MCO 36–48 (44; n = 06) long, elongate sclerotized sinuous tube, with numerous and uncountable coils, with counterclockwise orientation, base of MCO big and oval. Accesory piece sclerotized, 25–34 (30; n = 06) long, non-articulated to MCO, comprising a kind of cone, with a large opening at its base, with a branch in the posterior middle part and with pointed ends. Vagina sclerotized, a long, winding, coiled tube with a cone-shaped opening. Dextral. Seminal receptacle oval. Eggs, ootype, and uterus not observed. Vitellaria dense, coextensive with caeca.