Nybelinia sphyrnae Yamaguti, 1952

Palm, Harry Wilhelm & Haseli, Mohammad, 2023, Tentaculariids (Cestoda, Trypanorhyncha) of elasmobranchs from Malaysian Borneo, Zoosystema 45 (18), pp. 513-529 : 520-522

Nybelinia sphyrnae Yamaguti, 1952

Nybelinia sphyrnae Yamaguti, 1952: 56 .

Nybelinia jayapaulazariahi Reimer, 1980: 226 , n. syn.

MATERIAL EXAMINED. — Malaysia • 5 specimens; from Sphyrna cf. lewini (Griffith & Smith) (BO-69) ( Carcharhiniformes : Sphyrnidae ); Malaysian Borneo, off Mukah , Sarawak; 02°53’52.16”N, 112°05’44.12”E; LRP 4367 -4371 • 1 specimen; same data; ZMB E. 7726 • 1 specimen; from Sphyrna lewini 1 (sensu Naylor et al. 2012) (BO-60); off Mukah, Sarawak; 02°53’52.16”N, 112°05’44.12”E; LRP 11005 .

Japan • holotype and 1 paratype; from S. zygaena off Nagasaki; off Nagasaki; SY 7201 .

South Australia • 3 specimens; from S. zygaena off Goolwa ; SAM; AHC 24958 .

Malaysia • 1 specimen; from Urogymnus polylepis (Bleeker) (BO-108) ( Myliobatiformes : Dasyatidae ); Malaysian Borneo, off Kampung Abai, Kinabatangan River, Sabah; 05°41’10.81”N, 118°23’08.35”E; LRP 11006 .

New Caledonia • 7 plerocercoids; from Saurida undosquamis (Richardson) ( Aulopiformes : Synodontidae ); off New Caledonia; ZMB E. 7729-32 .

REMARKS

Nybelinia sphyrnae was described by Yamaguti (1952) from Sphyrna zygaena off Nagasaki, Japan. Beveridge & Campbell (1996) reported three specimens of this species from S. zygaena from Goolwa, South Australia, providing additional drawings of the scolex and mature proglottid and the first drawing of the tentacle with its hooks. Palm (2004) also reported this species from S. zygaena from Goolwa, South Australia, in his parasite-host checklist. Thereafter, Schaeffner & Beveridge (2014), during a large-scale study focusing on the parasite diversity of elasmobranchs from Malaysian and Indonesian Borneo, reported specimens of N. sphyrnae from S. lewini off Malaysian Borneo, the hosts having been registered in the Global Cestode Database as Sphyrna lewini 1 (BO-60) and S. cf. lewini (BO-69).

In the present study, in addition to examining the specimens of N. sphyrnae earlier identified by Schaeffner & Beveridge (2014) from S. lewini 1 and S. cf. lewini (BO-60, 69), we also measured the holotype as well as one paratype from Japan, some specimens from New Caledonia, and those South Australian specimens mentioned in the parasite-host checklist of Palm (2004) to clarify the range of measurements for N. sphyrnae (see Table 1 ). Furthermore, on the basis of recent examinations and the measurements at hand a proposal for a synonymy of the two species N. sphyrnae and N. jayapaulazariahi is made, both of which have a homeoacanthous, homeomorphous tentacular armature with uncinate hooks, which increase in size towards the metabasal part of the tentacle. In both species, the pars bothrialis is larger than the pars bulbosa and the retractor muscles originate at the base of the bulbs.

In Table 1 , the measurements of N. jayapaulazariahi from different studies are compared with those of the types and vouchers of N. sphyrnae from different localities. The ranges of the taxonomically important characters of N. jayapaulazariahi overlap with those of N. sphyrnae . Regarding the variation seen for the bulb width to length ratio in the Malaysian Bornean and New Caledonian specimens of N. sphyrnae in comparison to other conspecifics, it is worth mentioning that in all the specimens of N. sphyrnae the values measured for the pars bulbosa as well as the length of bulbs are uniform, for which such differences have rarely been described in trypanorhynchs (see Schaeffner & Beveridge 2013a), but a variation is seen in the width of the bulbs, which depends on the state of contraction during fixation. This situation can also be considered for the length of the tentacles, however, by re-measuring this character from figure 7 drawn by Reimer (1980), this value is 335 at maximum size and is very close to the lower bound of the range measured (350-400) by Yamaguti (1952). None of the taxonomic works carried out on N. jayapaulazariahi mentioned the number of the hook rows along the tentacle. However, about 30 rows can be counted at least from figure 7 of Reimer (1980), which is close to the number of the hook rows counted for the Malaysian Bornean and South Australian specimens of N. sphyrnae . Although Yamaguti (1952) described 12 hook rows along the tentacle for the types, from figure 83 drawn by him, at least 24 rows can be counted. By examining the type specimens, we could count 32 rows of hooks. According to these findings we consider N. jayapaulazariahi , the descriptions of which were based on the larval forms, a new synonym for N. sphyrnae .