Mymarothecioides altamirensis Soares and Domingues, 2019

Soares, Geusivam B., Magalhães, Keila X., Silva, Ana Carolina, Carneiro, Jânio S., Barbosa, Lucineia L., Costa, Nayna G. S. & Domingues, Marcus V., 2019, Monogenoids (Polyonchoinea, Dactylogyridae) from Hydrolycus armatus (Characiformes, Cynodontidae) with the description of a new species of Rhinoxenus and the proposal of a new genus from the Xingu River, Pará, Brazil, Zootaxa 4700 (2), pp. 229-245 : 236-238

Mymarothecioides altamirensis Soares and Domingues n. sp.

( Figs. 18–26 ; 44 )

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: 13 parasites per infected host.

Specimens deposited: Holotype, MPEG nº 189; 9 paratypes, MPEG n° 190–198.

Etymology: The specific name refers to the municipality of Altamira, Pará State, Brazil, where the type host was collected.

Zoobank Life Science Identifier: (LSID) for Mymarothecioides altamirensis n. sp. is urn:lsid:zoobank.org:act:EAF4D327-06BA-4D87-A9A2-91F7D1872401

Comparative measurements: see Table 3 .

Description (based on ten specimens, four mounted in Hoyer, six mounted in Gomori’s trichrome): Body fusiform, total length excluding haptor 310 (187–400; n= 6), total width at level of germarium 82 (62–95; n=6) ( Fig. 18 ). Cephalic margin tapered; moderately developed terminal lobes; three to four bilateral pairs of head organs with rod-shaped secretion; cephalic glands not observed. Accessory chromatic granules absent. Pharynx ovate, 23 (19–27; n= 6) long, 19 (16–20; n=6) wide. Testis saculiform, 72 (47–103; n=4) long, 37 (32–37; n=4) wide. Prostatic reservoir subspherical, posterior to MCO. MCO, 27 (26–28; n=2) long, with distal portion subtly expanded; base of MCO with sclerotized margin ( Fig. 19 , 44 ). Accessory piece comprising straight rod, distal portion with subterminal flap with hook, thumb. Germarium fusiform, 41 (16–55; n=3) long, 23 (22–24; n=3) wide. Eggs, Mehlis’ glands, seminal receptacle, ootype not observed. Vaginal aperture marginal (dextral), opening at level of vitelline commissure. Uterus delicate. Vitelline follicles dense. Peduncle broad; haptor subhexagonal, 93 (82–100; n=6) long, 94 (70–117; n=6) wide. Anchors dissimilar. Ventral anchor, outer 48 (47–49; n=3) long, inner 56 (54–59; n=3) long; base 22 (22–24; n=3); root tips covered with sclerotized cap variable in shape; heavily depressed superficial root, prominent deep root; slightly curved shaft and point; point extending just past level of the tip of the superficial root; distinct hump on superficial surface of base ( Fig. 25 ). Dorsal anchor, outer 33 (28–38; n=2) long, inner 36 (33–39; n=2) long; base 19 (n=2), with distinct hump on its superficial surface; slightly depressed superficial root, root tip covered with sclerotized cap variable in shape; prominent deep root; slightly curved shaft and point; point extending just past level of tip of superficial root ( Fig. 26 ). Ventral bar 72 (70–76; n=3) long, 13 (11–16; n=2) wide, slightly curved rod with anteromedial projection, rounded ends ( Fig. 23 ). Dorsal bar, 49 (47–50; n=3) long, 6 (5–6; n=3) wide, broadly U-shaped rod with rounded ends ( Fig. 24 ). Hooks similar in shape, with upright thumb, rounded, short shaft, slightly curved shaft and point, shank divided into two units; filamentous hook loop not observed; hook pairs 1–4, 21 (20–27; n=21) long; hook pairs 6– 7 ( Fig. 22 ), 25 (28–30; n=9) long ( Fig. 20 ); hook pair 5, 20 (n=2) long, shank with proximal dilatation comprising approximately 1/3 of the shank length ( Fig. 21 ) pairs 6– 7, 25 (28–30; n=9) long ( Fig. 22 ).

Remarks: Mymarothecioides altamirensis n. sp. differs from all other congeneric species by having a ventral anchor with a distinct hump on the superficial surface of its base and a heavily depressed superficial root.

Figures

FIGURES 18–26. Mymarothecioides altamirensis n. sp. 18. Composite whole-mount (ventral). 19. Copulatory complex. 20. Hook pair 1–4. 21. Hook pair 5. 22. Hook pair 6–7. 23. Ventral bar. 24. Dorsal bar. 25. Ventral anchor. 26. Dorsal anchor.

FIGURES 42–45. The copulatory complex of species of Mymarothecioides n. gen. 42. Mymarothecioides ararai n. sp. 43. Mymarothecioides xinguensis n. sp. 44. Mymarothecioides altamirensis n. sp. 45. Mymarothecioides germanoi n. sp.