Nesippus crypturus Heller, 1868

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 : 20-22

Nesippus crypturus Heller, 1868

Material examined. Five adult Ƥ from the gill arches of Carcharhinus brevipinna (Müller & Henle, 1839) caught off Ramsgate (30°53’S 30°20’E) during February 2000 and 1 Ƥ from a host caught off Kent Bay (30°57’S 30°17’E) during September 2006; 1 Ƥ from Carcharhinus limbatus (Valenciennes, in Müller & Henle, 1839) caught off Zinkwazi (29°12’S 31°27’E) during October 2005 and 4 Ƥ from a host caught off Warner Beach (30°05’S 30°52’E) during May 1996; 1 Ƥ from Galeocerdo cuvier (Peron & LeSueur, in LeSueur, 1822) caught off Salt Rock (29°30’S 31°15’E) during September 2005, 5 Ƥ from a host caught off Anstey’s Beach (29°55’S 31°01’E) during February 1996, 1 Ƥ from a host caught off Amanzimtoti (30°03’S 30°53’E) during June 2006 and 1 Ƥ from a host caught off Scottburgh (30°17’S 30°45’E) during November 2004; 3 Ƥ from S. zygaena caught off Leisure Bay (31°01’S 30°14’E) during November 2009; 7 Ƥ from S. mokarran caught off Umdloti (29°40’S 31°08’E) during February 1996 and 6 Ƥ from a host caught off Durban during November 2000. Additional to these, 2 Ƥ from C. carcharias caught off Richards Bay during October 2002; 2 Ƥ from Carcharhinus leucas (Valenciennes, in Müller & Henle, 1839) caught off Richards Bay also during October 2002 and 4 Ƥ from C. limbatus caught off Port Edward (31°03’S 30°14’E) during November 2009.

Supplementary description of the adult female. Mostly as described by Cressey (1967) with the following modifications or details: Adhesion pads anterolaterally on dorsal shield conically shaped ( Fig. 4 A), with that at base of antenna similar sized while post-oral adhesion pads are protruded and most prominent. Antennule with 2 flower-shaped processes amongst plumose setae on first segment ( Fig. 4 B), second segment with 2 longest setae terminally (see Cressey 1967, Fig. 308) being aesthetascs. Mandible ( Fig. 4 F) with 12 teeth. Maxilla ( Fig. 4 C) mostly similar to that of N. vespa . Legs 1–3 with spine on first segment and first two spines on second segment more pointed while next two spines are longer and finger-like ( Fig. 4 D). Leg 4 exopod ( Fig. 4 E) with 3 terminal and 1 distolateral spines (small spines invisible through light microscope present on distolateral border).

Comments on morphology. Females of N. crypturus seem to have two morphological forms. Morphoform 1 ( Fig. 5 A), collected from the first five hosts mentioned, has clear lateral expansions (although varying in size) on the 4th thoracic segment, a genital complex with broad anterolateral corners, abdomen attached almost midway on genital complex and caudal rami thus completely invisible in dorsal view. Morphoform 2 ( Fig. 5 B), collected from the additional three hosts mentioned, has very small to no lateral expansions on the 4th thoracic segment, a genital complex with slightly tapering anterolateral corners (also see Pillai 1985, Fig 47A), abdomen attached almost to the last 3rd of the genital complex and caudal rami that may be barely visible in dorsal view (also see Pillai 1985, Figs 47A, I).

Another important variation observed in the examined specimens was the endopod of leg 4 that sometimes is armed with a seta and/or knob-like process ( Figs 5 C, D) (also see Pillai 1985, Fig. 47H). This was noticed in one female collected from S. mokarran off Umdloti, one collected from C. leucas and one from C. limbatis collected off Port Edward. However, the same female from C. limbatus has an unarmed endopod on the other side ( Fig. 5 E).

Distinguishing characteristics. Fourth thoracic segment with or without lateral extensions, genital complex broad or slightly tapering anterolaterally with narrow neck-like region anteriorly and with deep median sinus posteriorly ( Figs 5 A, B; also see Pillai 1985, Fig. 47A and Cressey (1967), Fig. 305), caudal rami not visible or barely visible dorsally, protruded post-oral adhesion pads ( Fig. 4 A) similar to those in N. orientalis (see Dippenaar & Jordaan 2006, Fig. 2 D) but slightly more pointed, structure of exopodal spines ( Fig. 4 D), position of leg 4 exopod spines (3 terminally and 1 distolaterally) ( Fig. 4 E), caudal rami armed with 4 long pinnate setae, 2 small naked setae and fringe of medial setules (see Pillai 1985, Fig. 47I and Cressey 1967, Fig. 306).

Ecological aspects. Morphoform 1 exhibited 100% prevalence on S. mokarran , but with mean intensity and mean abundance values of below 10 individuals per host on all host species ( Fig. 6 ) while prevalence, mean intensity and mean abundance values are all below 10 for morphoform 2 on all the infected host species ( Fig. 6 ).

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 4. Nesippus crypturus Heller, 1868, adult female SEM micrographs. (A) Cephalothorax, ventral; (B) Antennule, first segment; (C) Maxilla, calamus; (D) Leg 2, exopod; (E) Leg 4; Line drawing of (F) Mandible. Scale bars: A, 200 µm; B, C, E,

FIGURE 5. Nesippus crypturus Heller, 1868, adult female SEM micrographs. (A) Morphoform 1, habitus ventral; (B) Morphoform 2, habitus ventral; Digital photographs through light microscope showing (C) Leg 4 endopod with armature (è); (D) Leg 4 endopod with armature (è); (E) Leg 4 endopod of same specimen without armature. Scale bars: A, B, 200 µm; C, 100 µm; D, E, 50 µm.

FIGURE 6. The prevalence (%), mean intensity and mean abundance of Nesippus crypturus Heller, 1868 on its different host species (* indicates morphoform 2 host species).