Heteronybelinia eureia (Dollfus, 1960)

Palm, Harry W. & Walter, Thorsten, 2000, Tentaculariid cestodes (Trypanorhyncha) from the Muséum national d’Histoire naturelle, Paris, Zoosystema 22 (4), pp. 641-666 : 654

Heteronybelinia eureia (Dollfus, 1960)

Nybelinia eureia Dollfus, 1960 .

MATERIAL EXAMINED.– Gorée. Senegal, adequately described in Dollfus (1960), holotype and 2 paratypes from an unidentified congrid ( Paraconger sp. ), Dakar, Senegal, and Mustelus canis (Mitchill, 1815) ( MNHN 709-711 HF).

REMARKS

Heteronybelinia eureia has a heteromorphous tentacular armature consisting of slender hooks. The species is similar to Mixonybelinia edwinlintoni in its hook form and size (see below). However, the basal hooks within H. eureia are heteromorphous.

Heteronybelinia minima Palm, 1999 (Fig.7)

MATERIAL EXAMINED. — Algiers. Algeria, leg. M. Hanior, 2 postlarvae from the gills of Chelidonichthys obscura (Bloch & Schneider, 1801) ( MNHN 782-783 HF).

DESCRIPTION

sl = 826, 994; sw = 462, 994; pbo = 336, 462; pv = 252, 448; pb = 224, 267; app = 378, 273; vel = 179, 113; bl = 206 (197-214), 186 (159- 217); bw = 64 (62-66), 68 (62-72); br = 3.2:1, 2.7:1; sp = 1.5:1.1:1, 1.7:1.7:1. The tentacles are long, when inverted nearly reaching the apical end of the bulbs, tsw = 27-28, 25-28; tw basal 29, 28, a basal tentacular swelling is absent. Prebulbar organs are absent, a muscular ring around the basal part of the tentacle sheaths is visible within one specimen. The retractor muscles originate at the base of the bulbs.

The tentacular armature is homeoacanthous, heteromorphous and a characteristic basal armature is absent (Fig.7C). The hooks diminish in size towards the basal part of the tentacle, the hook forms differ from compact and rose-thornshaped (bothridial) to slender falcate hooks with a stout base (antibothridial). The hook size in the metabasal armature of both specimens respectively ranges between l = 16.0-16.5, 17.5-18.0; b = 6.5-8.0, 9.5-10.0 (bothridial) and l = 16.5-17.0, 18.5-19.0; b = 6.0-7.0, 7.5-8.2 (antibothridial), and the hook size within the basal part of the tentacle was between l = 9.5-11.5, 9.5-11.5; b = 9.5-

10, 9.5-10.0 (bothridial) and l = 7-8.5, 7-8.5.0;

b = 4.0-6.0, 4.0-6.0 (antibothridial); hsr = 6.

REMARKS

The present specimens, found encapsulated in the gills of Chelidonichthys obscura , were identified as Heteronybelinia minima , though having smaller tentacular hooks than was observed in the type specimens by Palm (1999). Similarly, the hook form appeared to be more slender on the bothridial tentacle surface. However, the scolex morphology as well as scolex measurements appeared to be similar (Palm 1999: fig.34). The tentacles were not visible from the same angle as in the type specimens, thus the shape of the tentacular hooks is not directly comparable with the types (BMNH). In both lots of material, the tentacular hooks increase distinctly in size towards the metabasal region on the bothridial and antibothridial tentacle surfaces, and in the types, the hooks decrease in size from the seventh row towards the apex. Thus, until better material becomes available, the present specimens are identified as H. minima , representing a new host and locality record from the Mediterranean.

Specimen MNHN 783 HF illustrates an interesting accidental case of “hyperparasitism”. A second specimen of H. minima was found completely enclosed within a sl = 980 long H. minima (Fig.7B).

There appeared to be some space between the hyperparasite and the host tissue. Both specimens were situated within a single host capsule. A similar accidental case of hyperparasitism has been recorded for the tentaculariid Tentacularia coryphaenae which was found within a specimen of Phyllobothrium (Tetraphyllidea) (Gaevskaja 1978) .