Acanthobothrium halehae, Maleki & Malek & Palm, 2019

Maleki, Loghman, Malek, Masoumeh & Palm, Harry W., 2019, Five new species of Acanthobothrium (Cestoda: Onchoproteocephalidea) from the long-tailed butterfly ray, Gymnura cf. poecilura (Elasmobranchii: Gymnuridae) from the Persian Gulf and Gulf of Oman, Zootaxa 4609 (2), pp. 289-307 : 294-298

Acanthobothrium halehae n. sp.

( Figs. 22–25 , 31–36 )

Type host: Gymnura cf. poecilura , Long-tailed butterfly ray ( Myliobatiformes : Gymnuridae )

Type locality: Gulf of Oman (25° 11´N, 60° 33´E – 25° 25´N, 57° 43´E) , Iran.

Additional localities: None.

Site of infection: Spiral intestine.

ZooBank registration: The Life Science Identifier (LSID) urn:lsid:zoobank.org:act:74BB1D9E-E4EA-42C1-8E49-BD98002FE61B .

Deposited material: Holotype ( ZCUOK. 127), 3 paratypes ( ZCUOK 128 – ZCUOK 130 ), 2 paratypes ( ZUTC Platy. 1342, ZUTC Platy. 1343), 1 SEM voucher ( ZUTC Platy. 1344).

Prevalence of infection: 6.6% (2 of 30 individual examined).

Etymology: This new species is named after Mrs. Haleh Ghaemolsabahi, for her contribution to the organization of the Global Cestoda Database website.

Description: Based on whole mounts of 6 mature worms, 1 scolex examined with SEM, and a whole mount of its voucher. Worms 3.05–6.47 mm (4.4±1.2; 6; 6) long, greatest width at scolex; 10–22 (17.6±4.8; 6; 6) proglottids per worm; worms apolytic. Scolex consists of scolex proper and conspicuous cephalic peduncle. Scolex proper with 4 bothridia, 193–251 (226±21; 6; 6) long. Bothridia free posteriorly, 280–347 (311±24; 6; 7) long by 108–152 (133±19.4; 6; 8) wide; each with 3 loculi separated by two transverse septa, and a specialized anterior region in form of a muscular pad; muscular pad 62–83 (75±7.4; 6; 7) long by 80–124 (102±15.6; 6; 7) wide, round in shape, consisting of apical sucker and 1 pair of hooks at posterior margin; accessory sucker 30–36 (32±2.7; 6; 7) long by 37–54 (45±7; 6; 7) wide; anterior loculus with two lappets at posterolateral margins, 127–178 (147±19.6; 6; 7) long; middle loculus 37–56 (46±5.8; 6; 7) long; posterior loculus 55–83 (66±10.8; 6; 7) long; ratio of locular length (anterior: middle: posterior) 1: 0.25–0.36: 0.3–0.61; maximum width of scolex, 216–300 (257±33.8; 6; 6), at level of anterior loculus. Velum between pair of adjacent bothridia present.

Hooks bipronged, hollow, with tubercle on proximal surface of axial prong; internal channels of axial and abaxial prongs continuous, lateral and medial hooks equal in size; axial prongs slightly longer than abaxial prongs. Lateral hook measurements: A 31–40 (35±3.9; 6; 6), B 57–76 (66±7.5; 6; 6), C 40–52 (46±3; 6; 6), D 85–109 (97±9.9; 6; 6), E 72–86 (81±5.1; 6; 6), W 35–46 (38±4, 6; 6). Medial hook measurements: A´ 28–41 (35±5.5; 6; 7), B´ 60–77 (66±6.9; 6; 6), C´ 33–49 (44±6.4, 6; 6), D´ 86–109 (98±9.6, 6; 6), E´ 64–92 (79±10.3; 6; 6), W´ 26–47 (37±7.2; 6; 6). Bases of lateral and medial hooks approximately equal in length; hook bases embedded in muscular pad, bases covered with an encrusted sclerotisation. Cephalic peduncle 92–255 (143±59.8; 6; 6) long by 75–135 (101±19.8; 6; 6) wide at mid-level.

Apical pad surface ( Figs. 32, 33 ) and distal bothridial surface ( Fig. 35 ) covered with papilliform filitriches. Proximal bothridial surfaces covered with papilliform to slightly acicular filitriches ( Fig. 34 ). Cephalic peduncle surface ( Fig. 36 ) covered with densely arranged gladiate spinitriches.

Proglottids acraspedote, protandrous. Immature proglottids 6–17 (13±4.3; 6; 6) in number; mature proglottids 3–5 (3.6±1; 6; 6) in number. Mature proglottid 518–1041 (716±211; 7; 7) long by 200–256 (232±21.9; 7; 7) wide, length:width ratio 2.3–4 (3±0.6; 7; 7):1. Gravid proglottids 0–1 (0.8±0.4; 7; 7) in number. Terminal proglottid 702–1060 (924±147) long by 202–279 (250±29) wide. Genital pores lateral, near posterior margin of proglottid, alternating irregularly, 10–18% (13.8±2.7; 7; 7) of proglottid length from posterior end. Testes irregularly oval in dorsoventral view, 30–57 (43±8.5; 7; 10) long by 36–65 (53±11; 7; 10) wide, arranged in 2 regular columns well anterior to ovary, 30–37 (33±2.6; 7; 8) in total number, no testes post-vaginal, no testes posterior to ovarian field. Cirrus sac narrow, oval in mature proglottid, extending anteriorly along poral arm of ovary, 104–181 (140±26.3; 7; 7) long and 35–75 (55±14.8; 7; 7) wide, containing coiled cirrus; cirrus expanded at base; most of cirrus length covered with spinitriches. Vas deferens in mid-part of mature proglottid. Vagina short, thick walled, extending from o ӧtype along midline of proglottid to near anterior margin of poral lobe of ovary, then posteriorly following anterior margin of cirrus sac to common genital atrium; vaginal sphincter absent. Seminal receptacle not seen. Ovary located in posterior third part of proglottid, poral lobe slightly displaced by cirrus sac, symmetrical, 198–424 (248±73.8; 7; 7) long, maximum width of ovary 91–163 (131±30; 7; 7), H-shaped in dorsoventral view, lobulated; reaching to posterior margin of testes; ovarian isthmus near mid-point of ovary; Mehlis’ gland posterior to ovarian isthmus. Vitellarium follicular, consisting of two lateral bands; each band consists of 2 columns of follicles, extending from below anterior margin of testes to near anterior margin of ovary, interrupted by vagina and cirrus sac and ovary; Vitelline follicles irregular, 14–36 (24±8.5; 7; 7) long by 17–36 (24±5.9; 7; 7) wide. Uterus median, thin-walled, sacciform, extending from near anterior part of proglottid to near o ӧtype. Excretory ducts lateral. Eggs spherical, unembryonated in utero.

Remarks: Acanthobothrium halehae n. sp. is a Category 1 species, according to Ghoshroy & Caira (2001) (less than 15 mm in total length, fewer than 50 proglottids and fewer than 80 testes, symmetrical ovary). It can be easily distinguished from all 50 Category 1 species except A. kurdistanense n. sp., A. omanense n. sp. and A. fogeli Goldstein, 1964 in the position of the genital pore near posterior one-fifth of proglottids and orientation of the cirrus sac parallel to the ovarian lobes. The new species differs from A. fogeli in possessing shorter axial hook prongs (57–76 vs. 78–102). Acanthobothrium halehae n. sp. is longer (3.05–6.47 vs. 1.13–2.58), has smaller hook lengths (85-109 vs. 111-125) and a longer cephalic peduncle in comparison with A. kurdistanense n. sp. (92–255 vs. 36–82). The new species has a smaller muscular pad (62–83 vs. 85–108), and is apolytic rather than euapolytic, as is the condition of A. omanense n. sp. A. halehae n. sp. has more posterior genital pore (10–18%) than other Acanthobothrium species in the Persian Gulf and Gulf of Oman (see remarks above).

Figures

FIGURES 22–26. Acanthobothrium halehae sp. n. 22. Scolex.Arrows show the marginal lappets. 23. Whole worm. 24. Terminal proglottid. 25. Terminal genitalia. 26. Hooks. Scale bars: Figs. 22, 25, 26= 50 µm; Figs. 23, 24=100 µm.

FIGURES 31–42. FIGURES 31–36. Scanning electron micrographs of Acanthobothrium halehae n. sp. 31. Scolex. Note: Small numbers on scolex correspond to the figures showing higher magnification images of these surfaces, and white arrow tip show the marginal lappet. 32. Apical pad and hooks. 33. Surface of apical pad. 34. Proximal bothridial surface. 35. Distal bothridial surface. 36. Cephalic peduncle surface. FIGURES 37–42. Scanning electron micrographs of Acanthobothrium makranense n. sp. 37. Scolex. 38. Apical pad and hooks. 39. Surface of apical pad..40. Proximal bothridial surface. 41. Distal bothridial surface. 42. Cephalic peduncle surface. Scale bars: Fig 31=100 µm; Fig. 37=70 µm; Fig. 38=50 µm; Fig. 32=40 µm; Figs. 36, 42=2 µm; Figs. 33, 34, 35, 39, 40, 41=1 µm.