Nybelinia cf. lingualis (Cuvier, 1817)

Palm, Harry W. & Walter, Thorsten, 2000, Tentaculariid cestodes (Trypanorhyncha) from the Muséum national d’Histoire naturelle, Paris, Zoosystema 22 (4), pp. 641-666 : 647-649

Nybelinia cf. lingualis (Cuvier, 1817)

MATERIAL EXAMINED.— Arcachon. Gironde, France, 1949, leg. H. Nouvel, 2 postlarvae from Chelidonichthys lucerna (Linnaeus, 1758) ( Trigla lucerna ) ( MNHN 767-768 HF).

DESCRIPTION

sl = 1620, 1100; sw = 765, 672; pbo = 966, 616; pv = 714, nm; pb = 392, 336; ppb = 252, nm; app = 470, 182; vel = 266, 308; bl = 364 (350- 378), 299 (294-308); bw = 118 (107-127), 110 (98-119); br = 3.1:1, 2.7:1; sp = 2.5:1.8:1, nm. The tentacle sheaths are coiled, tsw = 35-40, 38- 41. Prebulbar organs and muscular rings around the basal part of the tentacle sheaths not visible. The retractor muscles originate in the basal part of the bulbs. The tentacles are not completely evaginated, a basal tentacular swelling is absent, tw basal = 44, 40. The basal tentacular armature is homeoacanthous, homeomorphous and consists of compact rose-thorn-shaped hooks diminishing in size towards the basal part of the tentacles (l = 7.6-10.0, 6.9-10.0; b = 6.8-9.1, 6.2- 9.0); hsr = nm, 6-7.

REMARKS

The tentacles of the present specimens were not completely evaginated, which would enable a definitive identification as N. lingualis or N. riseri .However, the scolex-form is similar to N. lingualis , as illustrated by Dollfus (1942). The specimens are therefore identified as N. cf. lingualis .

Nybelinia riseri Dollfus, 1960 ( Fig.3 )

MATERIAL EXAMINED.— Monterey. USA, 21. V.1948,

leg. N. W. Riser, holotype and 1 paratype, postlarvae from the stomach contents of Raja binoculata Girard, 1855 ( MNHN 694 HF).

Concarneau. France, 02.VII.1951, leg. R. Legendre,

4 postlarvae from the body cavity of Mullus surmuletus Linnaeus, 1758 ( MNHN 695 HF, 769-770 HF). SUPPLEMENTAL DATA.— The holotype was adequately described by Dollfus (1960). The basal and metabasal tentacular armature of the paratype and the apical armature of a specimen from Mullus surmuletus are shown in Fig.3.

DESCRIPTION

Measurements of the paratype and four specimens from M. surmuletus , sl = 1665, 1716 (1465- 1890); sw = 600, 928 (630-980); pbo = 826, 938 (770-1005); pv = 630, 1000 (798-1150); pb = 378, 294 (252-350); ppb = 21, 8 (5-10); vel = 245, 448 (336-532); app = 623, nm, nm, 434,

nm; bl = 362 (350-371), 256 (238-280), 259 (252-266), 226 (214-234), nm; bw = 121 (116- 131), 112 (98-126), 130 (126-140), 127 (124- 134), nm; br = 3.0:1, 2.3:1, 2.0:1, 1.8:1, nm;

sp = 2.2:0.6:1, 2.9:3.0:1, 3.5:4.0:1, 3.1:3.2:1,

nm; tw basal = 52-55, 38-41, 38-41, 38-41, 52-

55; tw metabasal = 31-34, 31-34, 31-34, 34-36, 45-48; tw apical = 24-25 (paratype). A basal tentacular swelling is absent. The tentacle sheaths are straight; tsw = 30-40, 34-35, 31-35, 40-44, nm.

Prebulbar organs are absent, muscular rings around the basal part of the tentacle sheaths are present. The retractor muscles originate in the basal part of the bulbs.

The armature is homeoacanthous, homeomorphous and a characteristic basal armature is present, consisting of about 10 rows. The tentacular hook form changes towards the metabasal part of the tentacle from compact, rounded rose-thornshaped ( Fig.3A ), lacking an anterior extension of the basal plate (uncinate), to more slender rosethorn-shaped hooks with a slight anterior extension ( Fig.3B, C ). The hooks in the basal part of the tentacle are smaller (l = 7.0-11.1, 10.0-14.2, 10.0-14.2, 10.1-15.2, 10.2-14.1; b = 8.0-12.1, 7.0-10.1, 6.9-14.1, 8.9-14.1, 7.0-10.2) than in the metabasal armature (l = 13.2-17.1, 16.1-17.2, 19.1-21.3, 18.9-21.1, 17.0-19.1; b = 12.1-13.2, 12.0-13.3, 12.1-16.2, 14.1-14.9, 13.0-14.1), the apical hooks increase slightly in size. The number of hooks per half spiral diminishes towards the apical part of the tentacle; hsr = 7-8, 6-7, 7-8, 6-7, 7-8 (basal), hsr paratype = 4-5 (apical).

REMARKS

Dollfus (1960) described a specimen of Nybelinia riseri with incompletely evaginated tentacles. On the slide with the holotype, a second specimen with nearly completely evaginated tentacles reveals a characteristic armature consisting of compact, rounded rose-thornshaped basal hooks, lacking an anterior extension of the basal plate, and more slender rose-thorn-shaped metabasal hooks. However, in contrast to N. lingualis , the apical hook form remains similar to that seen on the metabasal part of the tentacle, and the hooks increase slightly in size. Together with the characteristic mushroom shaped scolex, this character distinguishes Nybelinia riseri from N. lingualis . Both species are closely related, and N. riseri changes its position from subgroup 1Aa to subgroup 1Ba in Palm et al. (1997).

Palm (1999) identified Nybelinia specimens from Trachyurus felicipes (unrecognisable binomen) from the South African coast as Nybelinia riseri , indicating however, that only the first part of the tentacle was evaginated. The confirmation of the validity of Nybelinia riseri with its characteristic scolex form supports the assignment of these specimens to N. riseri . The present finding extends the distribution of N. riseri to the Mediterranean and South Africa and represents two new host records.

Nybelinia scoliodoni (Vijayalakshmi ,

Figures

FIG. 3. — Nybelinia riseri; A, B, from Raja binoculata; A, basal armature; B, metabasal armature; C, from Mullus surmuletus, apical armature. Scale bar: 25 µm.