Caligus furcisetifer Redkar, Rangnekar & Murti 1949

Caligus furcisetifer Redkar, Rangnekar & Murti, 1949 (Figs 27A – 28B) Host: Carcharias taurus Rafinesque (Carchariidae: Lamniformes) Locality: Off east coast South Africa (Indian Ocean) Material examined: 6♀ + 3♂ Material collected: 32♀ + 15♂ from C. taurus Voucher material: 3♀ + 3♂ (SAMC-A099212) from C. taurus deposited in the Iziko South African Museum, Cape Town, South Africa. Adult female (Fig. 27A) frontal plates with small, inconspicuous lunules; genital complex about as long as wide; abdomen small, 1-segmented; antenna (a2) with small, tapering proximal process (arrowed), claw slender with curved tip (Fig. 27B); post-antennal process (pap) with tapering, slightly curved tine with marginal flange (Figs 27B, 28B); maxillule with dentiform posterior process (mpp) tapering, straight (Figs 27B, C); sternal furca (sf) with slightly divergent, blunt-ended tines (Fig. 27C); leg 1 last exopodal segment with 3 posterior pinnate setae (ps), terminal seta 4 (4) shorter than terminal spines 2–3, spine 3 (ts3) shorter than spine 2 (ts2) (Fig. 27D); leg 2 exopod segment 1 distolateral spine (arrowed) obliquely over surface of ramus, segment 2 distolateral spine (arrowed) aligned closer to longitudinal axis of ramus (Fig. 27E); leg 3 exopodal segment 1 distolateral spine (ds) large, tapering (Fig. 27F); leg 4 3-segmented with I, III spines, medial terminal spine (III) almost 3x longer than lateral terminal spines (II, I) (Fig. 28A) (cf. Pillai 1985; Boxshall 2018). Remarks: This species shares most of the distinguishing characteristics with the C. macarovi -group i.e. leg 4 structure (I, III spines), leg 1 last exopodal segment with 3 pinnate posterior setae, antenna with a proximal process, but the terminal seta 4 on the last exopodal segment of leg 1 is shorter rather than markedly longer than terminal spines 1–3. The total length of the examined specimens (around 6.2 mm) falls between that reported by Boxshall (2018) (i.e. 8.07 mm) and that reported by Pillai (1985) (i.e. 5.3 mm). Additionally, the proximal process on the first segment of the antenna seems smaller and less sharply pointed than those illustrated by Pillai (1985) and Boxshall (2018) (cf. Fig. 94B in Pillai (1985) and Fig. 29B in Boxshall (2018)) while the post-antennal process (pap) tine has a marginal flange (see Fig. 28B) in the examined specimens. Furthermore, the tines of the sternal furca in the examined specimens are not as widely apart as those illustrated by Pillai (1985) and Boxshall (2018) (cf. Fig. 94D in Pillai (1985) and Fig. 29C in Boxshall (2018)). This species has been reported before off South Africa, collected from the same host species, as Lepeophtheirus natalensis Kensley & Grindley (Dippenaar 2004). However, L. natalensis was synonymized with C. furcisetifer (see Hayes et al. 2021) and reported as such (Dippenaar 2024). Included in the examined specimens are many more specimens collected after the original reports (Dippenaar & Jordaan 2007) and thus it is important to note that C. furcisetifer is often encountered on C. taurus in South African waters.