Metapolystoma vencesi, Landman & Verneau & Raharivololoniaina & Preez, 2021

Landman, Willem, Verneau, Olivier, Raharivololoniaina, Liliane & Preez, Louis du, 2021, First record of Metapolystoma (Monogenea: Polystomatidae) from Boophis tree frogs in Madagascar, with the description of five new species, International Journal for Parasitology: Parasites and Wildlife 14, pp. 161-178 : 165-166

3.1.1. Metapolystoma vencesi n. sp. ( Fig. 2‒3 ; Table 2 )

3.1.1.1. Type host. Boophis albilabris ( Mantellidae )

3.1.1.2. Type locality. Ambatolahy , Madagascar (Fig. 1), (21.2438667S; 47.4262167E).

3.1.1.3. Site in host. Urinary bladder.

3.1.1.4. Level of infection. One of six frogs examined from Ambatolahy was infected with one mature and four juvenile parasites (prevalence 16.6%). One of four frogs examined from Ambohitantely was infected with seven mature parasites (prevalence 25%). The prevalence for the combined sample was 20% and the mean intensity 6.5.

3.1.1.5. Type material. The morphological description is based on six mature, ten oncomiracidia and four juvenile parasites. Three specimens were sexually mature (Holotype NMBP 578 ; Paratypes NMBP 579–580 ) and two immature (Paratypes NMBP 581–582 ). The holotype and paratypes NMBP 581 and NMBP 582 originated from Ambatolahy, Madagascar, while paratypes NMBP 579 and NMBP 580 originated from Andringita Massif , Madagascar . Juvenile parasites and oncomiracidia were used for marginal hook measurements and drawings. The type material was deposited in the parasitic worm collection, National Museum, Aliwal Street, Bloemfontein 9301, South Africa.

3.1.1.6. Voucher material. Remaining specimens in polystome collection, North-West University, Potchefstroom, South Africa.

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ventral, surrounded by false oral sucker. Posterior haptor 16% of body length, bearing three pairs of haptoral suckers of equal size. Marginal hooklets placed as for other polystomes: pairs one and two between hamuli, pairs three to five embedded in suckers, pairs six to eight found between anterior suckers, pairs one and eight larger than pairs two to seven ( Fig. 3a ). Well-developed hamuli between posterior-most haptoral suckers without cut between handle and guard ( Fig. 3b ). Medial pharynx length greater than width, positioned immediately posterior or at the margin of false oral sucker. Intestine bifurcates immediately posterior to pharynx, 8% of total length from most anterior point, converging posteriorly at position of 80% of total length from most anterior point, extending into haptor; no prehaptoral anastomoses. Lateral diverticula length equal to width, found only in last third of intestine. Medial diverticula only posterior to ovary, length greater than width.

Testis follicular, positioned in a narrow band posterior to the ovary, ventral to intestine. Vas deferens widens anteriorly to form sinuous semen vesicle 20–32 (27 ± 5; 1) wide, 179 long, 2% of body length, narrowing towards genital bulb, opening in common genital opening. Genital pore opening on left ventral half, posterior to intestinal ceca bifurcation, 10% of total length from most anterior point. Genital bulb muscular, surrounded by glandular cells, armed with genital crown bearing eight genital spines ( Fig. 3c ).

Ovary elongate, not lobed, positioned posterior to midbody, length 4.4 times greater than width, measuring 9% of body length. Oviduct 596 long, 29–53 (30 ±7; 1) wide. Uterus massive and wide, occupying most of body proper, tubiform, convolute, containing 367 ovoid, operculate eggs; some with fully developed oncomiracidia. Hatched intrauterine oncomiracidia present. Mehlis’ gland obscure. Two vaginae 180–420 long, 16–31 wide, on lateral margins, bearing multiple marginal openings, vaginal vestibule elongate, positioned at 18% from anterior. Vitellaria extended throughout most of body and haptor, surrounds female reproductive organs. Genito-intestinal canal prominent, 580 long, 40–133 (62 ±28; 11) wide, situated posterior to ovary.

Figures

Fig. 2. Ventral view of Metapolystoma vencesi n. sp. holotype. Abbreviations: eg, egg; gb, genital bulb; gc, genito–intestinal canal; ha, hamuli; hp, haptor; ic, intestinal caecum; mo, mouth; oc, oncomiracidium; od, oviduct; oi, oo¨–vitelline canal; os, false oral sucker; ov, ovarium; ph, pharynx; su, sucker; sv, semen vesicle; te, testis; ut, uterus; va, vagina; vd, vas deferens; vi, vitelline; vv, vitello–vaginal canal.

Fig. 3. Metapolystoma vencesi n. sp. from Boophis doulioti. a, marginal hooklets 1 (top), 2–7 (middle) and 8 (bottom) from holotype and paratypes; b, hamuli from holotype; c, genital crown from holotype. Abbreviations: X, outer length; Y, inner length; Z, hook length.