Caligus temnodontis Brian 1924

Caligus cf. temnodontis Brian, 1924 (Figs 21A – 22C) Host: Pomatomus saltatrix (Linnaeus) (Pomatomidae: Scombriformes) Locality: Off east coast South Africa (Indian Ocean) Material examined: 6♀ + 3♂ Material collected: 12♀ + 3♂ from P. saltatrix Voucher material: 2♀ + 1♂ (SAMC-A099208) from P. saltatrix deposited in the Iziko South African Museum, Cape Town, South Africa. Adult female (Fig. 21A) genital complex longer than wide, longer than abdomen (about 1.8 times); abdomen long, indistinctly 2-segmented, genital complex and abdomen combined longer than cephalothorax (about 1.3 times); antenna (a2) with blunt proximal process (arrowed) (Fig. 21B), claw (cl) sharply bent (Fig. 21B); post-antennal process (pap) curved (Fig. 21B); small conical process (cp) between bases of antenna and post-antennal process (Fig. 21B); maxillule with blunt dentiform posterior process (mpp) (Figs 21C, D); sternal furca (sf) tines divergent, with slightly incurved tips (Figs 21C, D); leg 1 first exopodal segment with spinules on posterior margin, last exopodal segment with terminal seta 4 (4) longer than terminal spines (ts), but shorter than segment, small, thin vestige of posterior margin setae (arrowed) (Fig. 21E); leg 2 exopodal segments 1 and 2 with long distolateral spines (arrowed) lying obliquely across segments, last segment with small, straight outer spine (os) (Fig. 21F); leg 2 first endopodal segment distolateral margin and second endopodal segment outer margin with denticles (arrowed) (Fig. 22A); leg 3 first exopodal segment distolateral spine (ds) slightly curved, almost reaching distal margin of second segment (Fig. 22B); leg 4 3-segmented with I, IV spines (Fig. 22C), distolateral spine (dls) on first segment reaching more than half length of lateral spine (I) on compound segment, outer two terminal spines (II and III) of almost equal length, about half length of inner terminal spine (IV) (cf. Boxshall & El-Rashidy 2009; Özak et al. 2010). Remarks: The examined specimens of C. cf. temnodontis has a total body length of about 4 mm, which falls within the size range reported (Boxshall & El-Rashidy 2009; Özak et al. 2010). Differences are found in the length of the genital complex and abdomen with the genital complex about 1.8 times the abdomen length in the current specimens while the abdomen was reported as about the same length as the genital complex (Özak et al. 2010), the claw of the antenna seems more strongly curved than illustrated by Boxshall and El-Rashidy (2009) in fig. 7B and the proximal process seems shorter more similar to that illustrated by Özak et al. (2010) in fig. 1D. The most confusing difference is the length of the vestigial seta on the posterior margin of the last segment of the exopod of leg 1. This seta is very thin and hair-like in the current specimens and difficult to observe (see Fig. 21E), while those illustrated before are about half the length of seta 4 (cf. Fig. 8F in Boxshall & El-Rashidy (2009) and Fig. 2B in Özak et al. (2010)). Caligus haemulonis is very similar to current specimens of C. temnodontis regarding the body proportions with the length of the genital complex and abdomen combined about 1.3 times longer than the cephalothorax, the strongly bent antenna claw, the presence of an additional process between the bases of the antenna and the post-antennal process, the presence of single vestigial seta on the posterior margin of the leg 1 last exopodal segment and the length of leg 4 spines (Boxshall & El-Rashidy 2009). The presence of a pinnate seta on the posterior margin of the last exopodal segment of leg 1 vs the presence a naked vestige of a seta is the character that distinguishes between C. temnodontis and C. haemulonis in the key provided for species of the productus -group (Boxshall & El-Rashidy 2009), but the presence of a difficult to observe thin, hair-like seta in the current specimens made this distinction very difficult and thus it is recommended that these two species be re-examined for the validity of both. Nevertheless, the current specimens are identified as C. cf. temnodontis based on most of the other distinguishing features as well as features described for the male and the host reports of C. temnodontis. Caligus temnodontis has been reported from P. saltatrix off the east coast of South Africa, Indian Ocean (Boxshall & El-Rashidy 2009; Özak et al. 2010) as well as by Kensley & Grindley (1973) as C. cf. affinis (Özak et al. 2010).