Nesippus vespa Kirtisinghe, 1964

Dippenaar, Susan M. & Jordaan, Bea P., 2012, Notes on the morphology and ecology of the adult females of Nesippus species (Siphonostomatoida: Pandaridae) with a key for identification, Zootaxa 3170, pp. 18-30 : 19-20

Nesippus vespa Kirtisinghe, 1964

Material collected. From the gill arches of Rhina ancylostoma Bloch & Schneider, 1801 ; 313 adult Ƥ from a host caught off Trafalgar (30°57’S 30°17’E) during March 1991; 12 adult Ƥ from a host caught off Richards Bay (28°48’S 32°06’E) during November 2004; 2 adult Ƥ from a host caught off Durban (29°51’S 31°00’E) during May 2009 and 1 adult Ƥ from Rhynchobatus djiddensis (Forsskål, 1775) caught off Durban during October 2002.

Supplementary description of adult female. Mostly as described by Cressey (1967) with the following modifications or details: Caudal rami ( Fig. 2 A) bearing 6 pinnate setae. The thumbprint-shaped adhesion pads anterolaterally on dorsal shield are most prominent ( Fig. 2 B), adhesion pads at base of antenna smaller with post-oral adhesion pads less protruded and prominent compared to other species. Antennule ( Fig. 3 A), first segment armed with 11 pinnate, 2 naked setae, 2 shorter spines and about 5 small spiniform processes; second segment with 2 aesthetascs, 1 long and 3 shorter naked setae terminally followed by 4 naked setae posterodistally. Mandible ( Fig. 3 B) with 10 teeth. Maxillule ( Fig. 3 C) laterally compressed, exopod (palp according to Boxshall & Halsey (2004)) with 3 tiny naked setae (1 much smaller than the other 2); endopod (endite according to Boxshall & Halsey (2004)) bearing 1 prominent conical projection and one much smaller projection. Maxilla ( Fig. 2 C) brachiform; lacertus (syncoxa according to Boxshall & Halsey (2004)) broad, unarmed; brachium (basis according to Boxshall & Halsey (2004)) slender; calamus tapered, curved, with sides rimmed by thin serrate membrane; canna shorter than calamus, sides rimmed by serrate membrane; crista a tuft of setae surrounding a seta-like protrusion. Legs 1–4 with 3 outer spines on last exopod segment and legs 1–3 spines of 1st exopod segments all rimmed by serrate membranes while terminal spine has jagged outer margin and jagged inner margin bearing setules ( Fig. 2 D). All legs with pinnate setae (sometimes not clearly visible).

Distinguishing characteristics. A narrow 4th thoracic segment, genital complex broad anterolaterally with narrow neck-like region anteriorly and with deep median sinus posteriorly (see Pillai 1985, Fig. 51A; Cressey 1967, Fig. 346 and Kirtisinghe 1964, Fig. 115), pronounced adhesion pads anterolaterally on dorsal shield ( Fig. 2 B), elongated maxilliped claw ( Fig. 2 E) compared to other species, structure of exopodal spines ( Fig. 2 D), armature of leg 4 (exopod with 4 outer spines and 3 inner pinnate setae, endopod with 4 pinnate setae ( Pillai 1985; Cressey 1967 & Kirtisinghe 1964)), caudal rami armed with long, pinnate (mostly obvious) setae ( Fig. 2 A).

Ecological aspects. Nesippus vespa exhibits 100% prevalence on R. ancylostoma and 33.3% prevalence on R. djiddensis while mean intensity and mean abundance (116 individuals per host) is much higher on R. ancylostoma than on R. djiddensis (1 individual per host).

Figures

FIGURE 2. Nesippus vespa Kirtisinghe, 1964, adult female SEM micrographs. (A) caudal ramus; (B) cephalothorax, ventral; (C) maxilla; (D) spine structure leg 1 exopod; (E) maxilliped claw and myxal pad. Scale bars: A, C, E, 20 µm; B, 200 µm; D, 10 µm.

FIGURE 3. Nesippus vespa Kirtisinghe, 1964, adult female. (A) Antennule; (B) Mandible; (C) Maxillule. Scale bars: A, 50 µm; B, 10 µm; C, 25 µm.