Caligus mulli Rodrigues, Ozak, Silva & Boxshall 2018

Caligus mulli Rodrigues, Özak, Silva & Boxshall, 2018 (Figs 29A – 30C) Hosts: Thyrsites atun (Euphrasen) (Gempylidae: Scombriformes); Katsuwonus pelamis (Linnaeus) (Scombridae: Scombriformes) Locality: Off east coast South Africa (Indian Ocean)— K. pelamis; off west coast South Africa (Atlantic Ocean)— T. atun Material examined: 7♀ Material collected: 6♀ from T. atun; and 1♀ from K. pelamis Voucher material: 2♀ (SAMC-A099213) from T. atun deposited in the Iziko South African Museum, Cape Town, South Africa. Adult female (Fig. 29A) genital complex about 1.5 times longer than wide, posterolateral corners lobate; abdomen small, 1-segmented; antenna (a2) with tapering proximal process (arrowed), claw strongly curved (Fig. 29B); post-antennal process (pap) tine slightly curved with outer flange (Fig. 29B); maxillule with dentiform posterior process (mpp) almost straight with blunt tip surrounded by marginal flange (Fig. 29C); sternal furca with divergent, blunt-ended tines slightly curved inwards distally, surrounded by marginal flange (Fig. 29D); leg 1 last exopodal segment with 3 posterior pinnate setae (ps), terminal seta 4 (4) longer than terminal spines 1–3, shorter than segment (Fig. 29E); leg 2 exopod segment 1 and 2 distolateral spines (arrowed) obliquely over surface of ramus (Fig. 29F), endopodal segments 1 and 2 with setules (arrowed) along outer margins (Fig. 30A); leg 3 exopodal segment 1 distolateral spine (ds) almost straight, shorter than segment 2 (Fig. 30B); leg 4 3-segmented with I, IV spines, medial terminal spine (IV) about twice as long as distolateral spine (II) (Fig. 30C) (cf. Rodrigues et al. 2018; Özak pers. comm.). Remarks: This species shares features with the C. bonito -group of species, but with setules on the outer margins of the leg 2 second segment rather than large denticles or spinules and with the proximal process on the antenna well-developed. The reported body length of C. mulli is about 2.72 mm (Rodrigues et al. 2018) while the current examined specimens are larger and about 4.2 mm. Additionally, the post-antennal process tine, maxillule dentiform posterior process and the sternal furca tines are all surrounded by conspicuous marginal flanges while the sternal furca tines are slightly more divergent with the tips less incurving. Furthermore, the spine on the first exopodal segment of leg 3 is slightly curved, rather than straight. Caligus mulli was described from Mullus spp. (Mullidae:Mulliformes) while the current specimens were collected from hosts belonging to Scombriformes. Thus, this constitutes new host records for the species. Additionally, this is also the first record off South Africa.