Nybelinia pseudafricana, Palm & Haseli, 2023

Palm, Harry Wilhelm & Haseli, Mohammad, 2023, Tentaculariids (Cestoda, Trypanorhyncha) of elasmobranchs from Malaysian Borneo, Zoosystema 45 (18), pp. 513-529 : 518-520

Nybelinia pseudafricana n. sp.

( Figs 2 A-D; 3A-G)

urn:lsid:zoobank.org:act:989AEFB5-E48C-4A3E-AF49-372588089233

Nybelinia africana Dollfus, 1960: 798 (in part see Palm 2004), n. syn.

TYPE MATERIAL. — Holotype. Malaysia • 1 specimen; from stomach of Lamiopsis tephrodes (Fowler) ( Carcharhiniformes , Carcharhinidae ) (BO-74); Malaysian Borneo, Sarawak, off Mukah , 02°53’52.16”N, 112°05’44.12”E; LRP 11007 .

Paratypes. Malaysia • 4 specimens; same data as for holotype; LRP 11008 , ZMB E.7719-21 . Indonesia • 2 specimens (plerocercoids); from stomach wall of Trichiurus lepturus (Scombriformes, Trichiuridae ); South Java, off Pelabuhan Ratu ; 06°59’13.9”S, 106°32’37.4”E; MNHN-HEL 1926, 1927 .

VOUCHER MATERIAL. — Scolex (plerocercoid) of N. pseudafricana n. sp. (voucher specimen) from the stomach wall of Gempylus serpens Cuvier, Pelabuhan Ratu , Indonesia ( Jakob & Palm 2006), prepared for SEM.

ADDITIONAL SPECIMENS STUDIED. — Several specimens of N. africana (ZMB E. 7722-25, 5 slides) from Mullus surmuletus Linnaeus off Kalâat el-Andalous, Tunisia.

ETYMOLOGY. — The specific name is related to the similarity of the new species to N. africana .

DESCRIPTION

[Based on whole mounts of 3 specimens; plerocercoid from Gempylus serpens observed with SEM.]

Worms 28 875-48 500 (37 283, N =3) long, with 160-246 (N =2) proglottids; scolex compact ( Figs 2A ; 3A ), craspedote ( Fig. 2A ), 555-724 (628, N =3) long. Scolex width 427-451 (440, N =3) at level of pars bothrialis, 427-451 (440, N =3) at level of pars vaginalis, 288-338 (319, N =3) at level of pars bulbosa. Bothria 4 in number, sessile and elongate. Lineate spinitriches along bothrial borders present. Scolex and bothrial surface covered with capilliform (3-5) and papilliform (1) filitriches. Pars bothrialis 282-386 (346, N =3) long, overlapping pars bulbosa; pars vaginalis shorter than pars bothrialis, 185-370 (252, N =3) long; tentacle sheaths straight anteriorly, each with a single coil immediately anterior to bulb, 36-52 (47, N= 3, n= 10) in diameter; muscular ring around basal part of tentacle sheath not seen. Pars bulbosa 217-266 (241, N = 3) long; prebulbar organs and gland cells inside bulbs absent; bulbs 240-252 (246, N= 3, n= 6) long, 96-104 (99, N = 3, n = 6) wide, bulb width: length ratio 1.0: 2.3-2.5 (2.5, N= 3, n= 6); retractor muscles originating at posterior extremity of bulbs; pars post-bulbosa absent. Velum elongate, straight or scalloped, 80-113 (99, N =3) long. Scolex ratio (pars vaginalis: pars bothrialis: pars bulbosa) 1.0: 1.0-2.0: 0.6-1.4 (1.0: 1.5: 1.1, N=3).

Tentacles elongate, 720-1000 (900, N=1, n=3) long with c. 40 rows of hooks; basal swelling absent; tentacle width 32-36 (N =1, n= 2) at level of basal region, 40-42 (N= 1, n=2) at level of metabasal region. Hooks solid. Tentacular armature homeoacanthous, homeomorphous ( Fig. 2B, C ). Metabasal armature differing distinctly from basal armature. 2-3 rows of basal armature with uncinate hooks with distinct anterior extension of base, 10-12 (11, N =2, n=6) long, base 8-10 (9, N =2, n=5) long; metabasal hooks larger, slender falcate with small base and regularly curved tip, 20-25 long (22, N = 3, n= 14); base 6-8 (7, N= 3, n =15) long; apical hooks of not fully everted tentacles 22 (N= 1) long, base 7-8 (7, N = 1, n= 2) long. Number of hooks per half spiral row in basal and metabasal region of tentacle 5-6 (5, N =2, n= 2) and 6-7 (6, N =2, n= 3), respectively.

Proglottids acraspedote ( Fig. 2D ), apolytic; immature and mature proglottids wider than long. Mature proglottids 2-3 (N=2) in number, 400-1125 (690, N =2, n= 5) long, 675- 2500 (999, N =2, n =4) wide. Gravid proglottids 1000-1375 (N =1, n =2) long, 2625 wide (N=1, n =1). In mature proglottids, genital pore in anterior third of proglottid; genital pores alternate irregularly. Cirrus sac submarginal, elongate, 56-72 (64, N=1, n=2) long, 168-220 (194, N=1, n=2) wide, not reaching anterior end of proglottid; cirrus sac length: width ratio 1.0: 2.3-3.9 (3.1, N= 1, n= 2). Cirrus unarmed, coiled. Seminal vesicles absent. Vas deferens tightly coiled, running anteriorly medially and then posteriorly towards ovarian isthmus. Testes oval in shape, around 40 in diameter, arranged in single layer; testes number 70-75 (73, N =2, n=2) per proglottid, 9 testes anterior to cirrus sac (n =1). Ovary bilobed, located in centre of proglottid, 68-189 (106, N= 2, n= 4) long, 140-280 (189, N=2, n= 4) wide. Vitelline follicles circumcortical, round to oval in shape, 24-44 (33, N= 2, n= 5) long; 12-24 (18, N=2, n =5) wide.

REMARKS

The specimens presented here as a new species are those identified by Schaeffner & Beveridge (2014) as N. africana from Lamiopsis tephrodes (BO-74). Nybelinia pseudafricana n. sp. most closely resembles N. africana . Both species can be characterized by the presence of several rows of uncinate hooks at the base of the tentacular armature and the presence of falcate hooks along the tentacle. Nonetheless, the new species is distinguished from N. africana by the length of the metabasal hooks (20-25 vs 12.5-16) and the tentacle length (720-1000 vs 200) (see Palm 2004). In this respect, several Tunisian specimens of N. africana isolated from Mullus surmuletus caught off Kalâat el-Andalous, were also used for comparison with their characteristics as follows:scolex 632-828 (751, N =12) long; bulbs 186-270 (213, N= 9, n =9) long, 72-96 (86, N= 9, n= 9) wide, bulb width: length ratio 1.0: 1.9-3.0 (2.5, N= 9, n= 9); velum 240-345 (277, N= 8 n= 8) long; number of rows of hooks 17-19 (18, N= 5); metabasal hooks 12-17 (15, N=5, n= 5) long, base 3-6 (5, N =5, n= 5) long; tentacles 258-321 (294, N = 4, n= 4) long. Nybelinia pseudafricana n. sp., considering the Tunisian specimens, is also different from N. africana in the number of rows of hooks (40 vs 17-19). It is worth mentioning that this feature was not mentioned in the original description of N. africana (see Palm 2004).

Regardless of variation in scolex length as can be seen in species of Nybelinia (see Palm 2004), it is of note that the specimens earlier identified as N. africana in Indonesia, including the adult specimens isolated from Alopias superciliosus Lowe as well as Carcharhinus sp. and the plerocercoids isolated from Alepisaurus ferox Lowe , Brama dussumieri Cuvier , Conger cinereus Rüppell , Coryphaena hippurus L., Gempylus serpens Cuvier , Thyrsitoides marleyi Fowler , and Trichiurus lepturus (see Palm 2000, 2004; Jakob & Palm 2006), are re-identified as N. pseudafricana n. sp., and that this species is very common along the southern Java coast, Indonesia.

Likewise, the specimens reported as N. africana off Mozambique by Palm et al. (1997) are re-identified as N. pseudafricana n. sp. based on the scolex measurements and the length of their metabasal hooks (20-32). Thus, whereas N. pseudafricana n. sp. occurs in the Indo-Pacific region, the distribution of N. africana still remains mainly around Western Africa and in the Mediterranean Sea.

Examination of the scolex with SEM identified several rows of tiny pores ( Fig. 3B, D ), each parallel to one hook row, and serially placed along the tentacle. This is a novel feature, which had not earlier been described from trypanorhynchs. However, pores have been earlier reported already from the hooks of Molicola horridus (Goodsir, 1841) Dollfus, 1935 and Gymnorhynchus isuri Robinson, 1959 (see Knoff et al. 2004, 2007).

Figures

FIG. 2. — Nybelinia pseudafricana n. sp. holotype, ex Lamiopsis tephrodes: A, scolex; B, basal towards metabasal armature, bothrial surface; C, metabasal armature, bothrial surface; D, mature proglottid. Scale bars: A, D, 125 µm; B, C, 50 µm.

FIG. 3. — Surface ultrastructure of Nybelinia pseudafricana n. sp.: A, typical muscular scolex with triangular shaped bothria; B, metabasal armature; C, basal and metabasal armature; D, series of pores at the base of tentacular hooks; E, capilliform filitriches between the bothria; F, lineate spinitriches along bothrial borders with capilliform filitriches on proximal bothrial surface; G, lineate spinitriches at bothrial border with papilliform filitriches on distal bothrial surface. Scale bars: A, 30 µm; B, C, 10 µm; D-F, 2 µm; G, 6 µm.