Acanthobothrium makranense, 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 : 298-299

Acanthobothrium makranense n. sp.

( Figs. 27–30 , 37–42 )

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:4EC15BD6-8AD6-4DE4- B0F9 F6744EB33C49.

Deposited material: Holotype ( ZCUOK. 130), 5 paratypes ( ZCUOK 131 – ZCUOK 135 ), 6 paratypes ( ZUTC Platy. 1345– ZUTC Platy. 1350), 1 SEM voucher ( ZCUOK 139 ), 1 SEM voucher ( ZUTC Platy. 1350).

Prevalence of infection: 3.3% (1 of 30 individuals examined).

Etymology: This species is named after the Makran region, the coast from where the material has been collected.

Description: Based on whole mounts of 12 mature worms, 2 scoleces examined with SEM and 2 whole mounts of their voucher. Worms 1.73–4 mm (2.9±0.8; 12; 12) long, greatest width at terminal proglottid; 9–17 (12.5±2.5; 12; 12) proglottids per worm; worms apolytic. Scolex consists of scolex proper and short cephalic peduncle. Scolex

proper with 4 bothridia, 135–212 (181±25; 12; 7) long. Bothridia free posteriorly, 212–281 (266±31.4; 12; 11) long by 84–138 (110±16.9; 12; 11) wide; each with 3 loculi separated by two transverse septa, and specialized anterior region in form of muscular pad; muscular pad 30–69 (51±16.9; 12; 7) long by 54–97 (81±17; 12; 17) wide, triangular in shape, consisting of apical sucker and 1 pair of hooks at posterior margin; accessory sucker 18–30 (23±4.8; 12; 6) long by 26–45 (36±7; 12; 6) wide; anterior loculus with two lappets at posteriolateral margins, 89–150 (121±18; 12; 10) long; middle loculus 31–47 (40±4.5; 12; 10) long; posterior loculus 46–78 (62±9.6; 12; 10) long; ratio of locular length (anterior: middle: posterior) 1: 0.25–0.39: 0.46–0.57; maximum width of scolex, 177–254 (221±25.8; 12; 11), at level posterior margin 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 34–43 (37±2.9; 12; 7), B 63–71 (68±3.3; 12; 5), C 42–56 (49±5; 12; 5), D 97–110 (101±5.1; 12; 5), E 75–97 (86±7.4; 12; 6), W 29–38 (33±4.4, 12; 5). Medial hook measurements:A´ 31–46 (36±4.2; 12; 9), B´ 56–78 (71±7.2; 12; 8), C´ 43–92 (52±16, 12; 8), D´ 101–118 (108±6.3, 12; 6), E´ 74–90 (83±5.5; 12; 6), W´ 29–47 (37±8.6; 12; 5). Bases of lateral and medial hooks approximately equal in length; hook bases embedded in muscular pad, bases covered with a encrusted sclerotisation. Cephalic peduncle 38–80 (60±16.4; 12; 9) long by 47–110 (74±21; 12; 9) wide at mid-level.

Apical pad surface ( Figs. 38, 39 ), and distal bothridial surface ( Fig. 41 ) covered with papilliform filitriches. Proximal bothridial surfaces ( Fig. 40 ) covered with papilliform to slightly acicular filitriches. Cephalic peduncle surface ( Fig. 42 ) covered with densely arranged gladiate spinitriches.

Proglottids acraspedote, protandrous. Immature proglottids 7–12 (9.5±1.8; 12; 12) in number; mature proglottids 1–5 (2.1±1.1; 12; 12) in number. Terminal mature proglottid 381–797 (559±156; 14; 10) long by 180–272 (205±27.8; 14; 10) wide, length: width ratio 2.7–5.9 (4.2±0.6; 14; 10): 1. Gravid proglottids 0–2 (1±0.6; 14; 10) in number. Genital pores lateral, near posterior margin of proglottids, alternating irregularly, 10–17 % (13.5±2.2; 14; 11) of proglottid length from posterior end. Testes irregularly round to oval in dorsoventral view, 25–43 (34±5.6; 14; 17) long by 32–52 (42±5.7; 14; 17) wide, arranged in 2 regular columns anterior to ovary, 27–34 (30±2.2; 14; 12) in total number, no testes in post-vaginal field, no testes posterior to ovarian field. Cirrus sac narrow, oval in mature proglottid, extending anteriorly along poral arm of ovary, 85–183 (116±19.4; 14; 13) long and 32–52 (42±5.7; 14; 13) wide, containing less 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 anterior margin of poral lobe of ovary, and 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, 210–324 (275±35.5; 14; 14) long, maximum width of ovary 100–196 (133±28.7; 14; 3), H-shaped in dorsoventral view, lobulated; reaching 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 anterior margin of testes to near anterior margin of ovary, interrupted by vagina, cirrus sac and ovary, interrupted by vagina and cirrus sac and ovary. Vitelline follicles irregular, 11–39 (21±7.7; 14; 14) long by 13–29 (19±4.4; 14; 14) 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 makranense sp. n. is a Category 1 species according to the categorization system by Ghoshroy & Caira (2001) (<15 mm in total length, <50 proglottids, <80 testes, with symmetrical ovary). It differs from all 51 Category 1 species but 4 (three of them described above) in the position of the genital pore in near posterior one-fifth of proglottids, the lack of post-vaginal testes and the orientation of cirrus sac approximately parallel to the ovarian lobes. Acanthobothrium makranense n. sp. can be distinguished from A. halehae n. sp., A. omanense n. sp. and A. fogeli in the possession of a very short cephalic peduncle (38–80 vs. 92–255, 125–315 and 128–230, respectively). Acanthobothrium makranense n. sp. differs conspicuously from A. kurdistanense n. sp. in that it retains gravid proglottids on its strobila (apolytic vs. euapolytic), shorter bothridia (212–281 vs. 318–403) and shorter hook length (97–110 vs. 111–125). The genital pore position in A. makranense n. sp. (10–17%) is at the posterior end of proglottids, in contrast to the other Acanthobothrium species from the Persian Gulf and Gulf of Oman (see remarks above).

Figures

FIGURES 27–30. Acanthobothrium makranense n. sp. 27. Scolex. Arrow shows the marginal lappet. 28. Terminal proglottid. 29. Whole worm. 30. Hooks. Scale bars: Figs: 27, 30= 50 µm; Fig. 28, 29=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.