Mymarothecioides ararai Soares and Domingues n. sp.

(Figs. 27–33; 42)

Type host: Hydrolycus armatus (Jardine & Schomburgk) .

Site: Gills.

Type locality: Volta Grande-Xingu River, municipality of Altamira, Pará State, Brazil (03°21’15,7’’S; 52°11’47,5’’W), collected on June 13, 2015 .

Prevalence: 100% of three hosts examined.

Mean intensity: one parasite per infected host.

Specimens deposited: Holotype, MPEG nº 203; 2 paratypes, MPEG n° 204–205.

Etymology: The specific name honors the Arara native people from the Xingu Basin, Pará, Brazil.

Zoobank Life Science Identifier: (LSID) for Mymarothecioides ararai n. sp. is urn:lsid:zoobank.org:act: 85291EFD-9CD5-4746-9A5C-BFBABC761EA5

Comparative measurements: see Table 3.

Description (based on three specimens, two mounted in Hoyer, one mounted in Gomori’s trichrome): Body robust, fusiform, total length excluding haptor 1,200 (n= 1), total width at level of germarium 300 (n=1) (Fig. 27). Cephalic margin tapered; cephalic lobes poorly developed; three to four bilateral pairs of head organs with rodshaped secretion; cephalic glands not observed. Accessory chromatic granules present in cephalic area. Pharynx spherical, 74 (n= 1) long, 70 (n=1) wide. Testis massive, saccate, 120 (n=1) long, 60 (n=1) wide; prostatic reservoir saculiform, posterior to MCO. MCO, 74 (70–77; n=3) long, robust, with ax-shape at distal portion, small grooves at edges of distal opening; base of MCO with broad sclerotized margin (Fig. 28; 42). Accessory piece comprising straight rod, distal portion with subterminal flap with hook, thumb. Germarium bacilliform, 57(n=1) long, 25 (n=1) wide. Eggs, Mehlis’ glands, ootype not observed. Vaginal aperture marginal (dextral), opening at level of vitelline commissure; vaginal vestibule heavily muscular; vaginal canal straight. Seminal receptacle sub-spherical. Uterus delicate. Vitelline follicles dense. Peduncle long, tapered posteriorly; haptor globose, 112 (n=1) long, 137 (n=1) wide. Anchors similar, each with heavily divergent roots covered with sclerotized cap; short slightly curved shaft; elongate point extending to level of tip of superficial root. Ventral anchor, outer 69 (58–79; n=2) long, inner 45 (43–47; n= 2) long, base 55 (47– 62; n= 2) (Fig. 32). Dorsal anchor, outer 61 (52–70; n=2) long, inner 43 (39–47; n= 2) long, base 43 (36–49; n=2) (Fig. 33). Ventral bar, 67 (47–87; n=2) long, 25 (16–35; n=2) wide, slightly curved rod with sigmoid to straight anteromedial projection, rounded ends (Fig. 30). Dorsal bar, 58 (41–74; n=2) long, 12 (8–16; n=2) wide, broadly inverted U-shaped rod with rounded ends (Fig. 31). Hooks similar in shape, 34 (26–40; n=10) long, with upright thumb, rounded, slightly curved shaft and point, shank divided into two units, proximal unit compressed, distal unit inflated, distal unit with 1 ½ size of proximal unit; filamentous hook loop extended near to beginning of distal unit (Fig. 29).

Remarks: Mymarothecioides ararai n. sp. differs from the other congeneric species by possessing a combination of the following features: anchors with heavily divergent roots, short slightly curved shaft, elongate point, an MCO with ax-shape at distal portion, and a massive testis (twice as big than the germarium).