Caligus elasmobranchi Boxshall, 2018

Dippenaar, Susan M. & Sebone, Makwena M., 2025, Caligus (Caligidae: Siphonostomatoida) species off southern Africa with the description of C. pillaii sp. nov., Zootaxa 5686 (2), pp. 151-197 : 182-184

Caligus elasmobranchi Boxshall, 2018

( Figs 26A–F )

Hosts: Rhinoptera javanica Müller & Henle ( Rhinopteridae : Myliobatiformes ); Aetobatus narinari (Euphrasen) ( Aetobatidae : Myliobatiformes ); Carcharodon carcharias (Linnaeus) ( Lamnidae : Lamniformes )

Locality: Off east coast South Africa (Indian Ocean)

Material examined: 5♀

Material collected: 6♀ from R. javanica ; 1♀ from A. narinari ; and 1♀ from C. carcharias

Voucher material: 2♀ ( SAMC-A099211 ) from R. javanica deposited in the Iziko South African Museum , Cape Town, South Africa .

Adult female ( Fig. 26A ) genital complex slightly longer than wide; abdomen 1-segmented, longer than genital complex; antenna (a2) without proximal process, claw strongly curved; post-antennal process (pap) with slender, strongly curved tine ( Figs 26B, C ) and small protuberance (arrowed) at base ( Fig. 26C ); maxillule with dentiform posterior process (mpp) long, slender, slightly curved outwards ( Figs 26B, C ); sternal furca (sf) with long slender, slightly divergent tines ( Fig. 26B ); leg 1 last exopodal segment with 3 posterior pinnate setae (ps), terminal seta 4 (4) shorter than terminal spines (ts) 2–3 ( Fig. 26D ); leg 3 exopodal segment 1 distolateral spine (ds) straight, reaching beyond articulation between segments 2 and 3 ( Fig. 26E ); leg 4 long, almost reaching caudal rami ( Fig. 26A ), 3- segmented with I, III spines (arrowed) respectively, ornamented with numerous surface sensillae (s), terminal spines short (almost equal lengths), modified pecten on distomedial margin ( Fig. 26F ) (cf. Pillai 1985; Boxshall 2018).

Remarks: Caligus elasmobranchi shares the structure of leg 4 (I, III spines), the pinnate setae on leg 1 last exopod segment and the 1-segmented abdomen with the C. macarovi -group, but not the remaining features.

The body length of about 7 mm agrees with those previously reported ( Pillai 1985; Boxshall 2018) as well as the very long legs 4. The small protuberance at the base of the post-antennal process was illustrated previously (see Fig. 88C in Pillai (1985) and Fig. 27B in Boxshall (2018)) although not mentioned in the descriptions.

This represents a new report from South African waters while R. javanica , A. narinari and C. carcharias constitute new host reports. Additionally, this is the first report from Lamniformes since all previous reports were from Myliobatiformes and Rhinopristiformes ( Pillai 1985; Boxshall 2018).

Figures

FIGURE 26. Caligus elasmobranchi Boxshall adult female: A. adult female, dorsal view; B. cephalothorax, ventral view (a2 = antenna; pap = post-antennal process; mpp = maxillule posterior process; sf = sternal furca); C. cephalothorax, ventral view (pap = post-antennal process; mpp = maxillule posterior process; arrow = protuberance); D. leg 1 distal exopodal segment (4 = terminal seta 4; ps = posterior setae; ts = terminal spines); E. leg 3 exopod (ds = distolateral spine); F. leg 4 exopod (arrows = I, III spines respectively; s = sensillae).

FIGURE 27. Caligus furcisetifer Redkar, Rangnekar & Murti adult female: A. adult female and male, dorsal view; B. cephalothorax, ventral view (a2 = antenna; arrow = posterior process; pap = post-antennal process; mpp = maxillule posterior process); C. cephalothorax, ventral view (mpp = maxillule posterior process; sf = sternal furca); D. leg 1 exopod distal segment (4 = terminal seta 4; ps = posterior setae; ts3 = terminal spine 3; ts2 = terminal spine 2); E. leg 2 exopod (arrows = distolateral spines); F. leg 3 exopod segment 1 (ds = distolateral spine).