Caligus elasmobranchi Boxshall, 2018

Caligus elasmobranchi Boxshall, 2018 View in CoL

( Figs 26A–F View FIGURE 26 )

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 View FIGURE 26 ) 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 View FIGURE 26 ) and small protuberance (arrowed) at base ( Fig. 26C View FIGURE 26 ); maxillule with dentiform posterior process (mpp) long, slender, slightly curved outwards ( Figs 26B, C View FIGURE 26 ); sternal furca (sf) with long slender, slightly divergent tines ( Fig. 26B View FIGURE 26 ); leg 1 last exopodal segment with 3 posterior pinnate setae (ps), terminal seta 4 (4) shorter than terminal spines (ts) 2–3 ( Fig. 26D View FIGURE 26 ); leg 3 exopodal segment 1 distolateral spine (ds) straight, reaching beyond articulation between segments 2 and 3 ( Fig. 26E View FIGURE 26 ); leg 4 long, almost reaching caudal rami ( Fig. 26A View FIGURE 26 ), 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 View FIGURE 26 ) ( 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 View FIGURE 27 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).