Peruanocotyle chisholmae, Chero & Cruces & Sáez & Luque, 2018

Chero, Jhon D., Cruces, Celso L., Sáez, Gloria & Luque, José L., 2018, A new genus and species of the Dasybatotreminae Bychowsky, 1957 (Monogenea: Monocotylidae), parasitic on Hypanus dipterurus (Jordan & Gilbert) (Myliobatiformes: Dasyatidae) in the Southeastern Pacific Ocean off Peru, Zootaxa 4527 (3), pp. 347-356 : 350-351

Peruanocotyle chisholmae n. gen., n. sp.

( Figs. 1–8 )

Type host: Hypanus dipterurus ( Jordan & Gilbert) ( Myliobatiformes : Dasyatidae ), diamond stingray.

Site on host: Gill filaments.

Type locality: Callao, Lima, Peru (12°04'S, 77°10'W), South America .

Prevalence: 2 of 8 hosts infected (25%) with a total of 4 worms.

Mean intensity of infection: 2 monogeneans per infected host (range 1–3).

Type material: Holotype, CHIOC 39080 a; 3 paratypes, CHIOC 39080 b-d.

Etymology: The species is named in honor of Dr. Leslie Chisholm (The South Australian Museum, Australia) for her contribution to the systematics of Monocotylidae .

Description: Based on 1 specimen mounted in Gray and Wess medium and 3 specimens flattened under slight coverslip pressure and stained with Semichon's carmine. Body 7.13–7.65 (n = 3) mm long, 2.08–2.27 (n = 3) mm wide at level of posterior third of trunk, slightly constricted at level of testes ( Fig.1 ) Tegument smooth. Haptor wheel-shaped ( Fig. 1 ), 1.49–1.78 (n = 3) mm long, 1.38–1.94 (n = 3) mm wide, with one central loculus and eight peripheral loculi; marginal membrane delicate, uniform, 106–122 (n = 3) wide. Anchor 32–63 (n = 4) long, associated with posterolateral septa, with deep and superficial roots distinct; elongate deep root, having small protuberances distally; rounded and thick superficial root; slightly curved shaft and recurved point, point reaching level of tip of superficial root ( Fig. 3 ). Fourteen similar hooks, 14–15 (n = 8) long, distributed in the marginal membrane as depicted ( Fig. 1 ), each with short and curved point, protruding thumb and uniform shank with curved proximal tip; filamentous hook (FH) loop extending to near level of proximal end of shank ( Fig. 4 ). Anterior attachment organ well-developed, broadly ovoid, 1.36–1.57 (n = 3) mm long, 1.70–1.84 (n = 3) mm wide, having 79–91 oblique grooves and one anteromedial notch, overlapping anterior end of pharynx ( Figs. 1–2 ). Three anterior glands, one medial (amg) and two laterals (alg), well-developed having irregular shape ( Fig. 2 ). Peripheral glands (pg) encircling oral opening, 18–20 in number ( Fig. 2 ). Eye-spots absent. Mouth ventral, subterminal, surrounded by numerous dome-like papillae ( Fig. 2 ), each papilla 25–27 (n = 3) long. Pharynx muscular, subquadrangular, with gland cells surrounding posterior portion, 479–587 (n = 3) long, 555–611 (n = 3) wide, with 10–11 transversal muscular packets; esophagus short to indistinct. Intestinal bifurcation anterior to common genital aperture; intestinal caeca with large lateral and medial diverticula, extending from anterior to posterior end of body proper, some diverticula partially surround testes, not confluent posteriorly ( Figs. 1 , 7 ). Common genital pore unarmed. Testes ovate, 4 in number, 536–785 (n = 12) long, 335–472 (n = 12) wide, arranged in two groups limited to intercaecal field, well separated from posterior end of body ( Figs. 1 , 8 ). Vas deferens highly convoluted, runs anteriorly dorsal to vagina, narrowing and looping before joining seminal vesicle ( Figs. 1 , 8 ). Seminal vesicle almost fusiform, lying sinestrolateral to distal portion of oötype, continues as a sinuous duct, curves dorsal to ejaculatory bulb to right side of the body and goes to base of ejaculatory bulb, where it enters and form an internal seminal vesicle. Internal seminal vesicle bipartite ( Fig. 8 ). Ejaculatory duct, which arises from the internal seminal vesicle, having slightly sclerotized walls, with proximal and distal portion; proximal portion with criss-crossed creases; distal portion highly convoluted ( Fig. 8 ). Ejaculatory bulb well-developed, highly muscular, ovate, 362– 371 (n = 3) long, 217–265 (n = 3) wide, anteromedial to oötype; distal portion of ejaculatory bulb with numerous male accessory glands ( Fig. 8 ). Male copulatory organ sclerotized, whip-shaped, 1.18–1.20 (n = 2) mm long, comprising four connate tubes; distal end of MCO ending in four interlaced extensions, two of them armed with 14–15 fine spines ( Figs. 5–6 ). Accessory piece sclerotized, inverted T-shaped ( Fig. 5 ), 110–115 (n = 2) long. Ovary lying anterodextral to testicular field, 7 01–868 (n = 3) long, 760–836 (n = 3) wide, looping right intestinal cecum, not overlapping testicular field, with proximal and distal portions; proximal ovary with six clavate lobes, each 103– 154 (n = 8) long, 111–150 (n = 8) wide, ventral and slightly posterior to distal portion of ovary; distal ovary tubelike, strongly coiled, narrows to form short oviduct ( Fig. 8 ). Oötype 318–410 (n = 2) long, 240–290 (n = 2) wide, proximal end slightly sinuous ( Fig. 8 ). Vaginal pore unarmed, surrounded by numerous gland cells densely grouped, opening ventrally on left side, 2.31–2.46 (n = 3) mm from anterior end. Vagina weakly sclerotized, funnel-shaped, lying obliquely on left side of body anterior to ovary; gland cells surrounding along its entire length; proximal portion of vagina connected to ovate seminal receptacle by a narrow duct ( Fig. 8 ); seminal receptacle 117–137 (n = 2) long, 73–82 (n = 2) wide. Vitelline follicles dense, extending from prepharyngeal level to posterior end of trunk, absent in regions of reproductive organs, lateral fields of follicles confluent posterior to testes ( Fig. 1 ). Excretory bladders parallel, extending from pharyngeal region to level of intestinal bifurcation ( Fig. 1 ). Tetrahedral egg (albeit distorted) observed in oötype.

Remarks: Peruanocotyle chisholmae n. gen., n. sp. is the type species of the genus. The new species is characterized by having a whip-shaped male copulatory organ, ending in four interlaced extensions, two of them armed with fine spines.

Figures

FIGURES 1–6. Peruanocotyle chisholmae n. gen., n. sp. 1. Whole worm (ventral). 2. Anterior attachment organ. 3. Anchor. 4. Hook. 5. Male copulatory organ. 6. Distal end of the male copulatory organ. ABBREVIATIONS: alg; anterolateral gland; amg, anteromedial gland; asp, accessory sclerotized piece; bp, buccal papillae; exb, excretory bladder; gr, groove; op, oral opening; pg, peripheral gland.

FIGURES 7–8. Peruanocotyle chisholmae n. gen., n. sp. 7. Whole worm (ventral) showing the intestinal ceca. 8. Reproductive system. ABBREVIATIONS: aao, anterior attachment organ; do, distal ovary; ded, distal ejaculatory duct; eb, ejaculatory bulb; eg, egg; ha, haptor; isv, internal seminal vesicle; lvd, longitudinal vitelline duct; mag, male accessory glands; mco, male copulatory organ; oo, oötype; ovi, oviduct; ped, proximal ejaculatory duct; ph, pharynx; po, proximal ovary; sr, seminal receptacle; sv, seminal vesicle; t, testis; tvd, transverse vitelline duct; vd, vas deferens; ve, vasa efferentia; vg, vaginal glands; vp, vaginal pore.