The sea lice (Copepoda: Caligidae) of Moreton Bay (Queensland, Australia), with descriptions of thirteen new species Author Boxshall, Geoff text Zootaxa 2018 2018-03-19 4398 1 1 172 journal article 30482 10.11646/zootaxa.4398.1.1 e5a58990-d727-440a-aab9-7638a5698954 1175-5326 1202953 79E3EB78-D1C3-45CF-AB13-F8E61C936252 Caligus brevicaudus Pillai, 1963 ( Fig. 23 ) Material examined. 2♀♀, 1♂ from Caranx ignobilis (Forsskål, 1775) (TC17579) 25 June 2016 ; 1♀, 1♂ QM Reg. No. W53059 ; 1♀ NHMUK Reg. No. 2017.248. Site on host. gill arches. Differential diagnosis. Cephalothorax dorsoventrally flattened with well-developed marginal membranes along lateral zones; frontal plates with lunules ( Fig. 23A ); thoracic zone small, posterior margin about level with posterior margins of lateral zones. Genital complex about 1.1 to 1.2 times longer than wide; abdomen small, 1- segmented, wider than long; genital complex about 4.3 times longer than abdomen (including caudal rami). Antenna with well developed posterior process on proximal segment. Post-antennal process bifid ( Fig. 23B ), tine without marginal flange; associated papillae bisensillate, unisensillate papilla on adjacent cephalothoracic surface. Posterior process of maxillule bifid ( Fig. 23C ); smaller outer tine arising near base of main (inner) tine. Maxilliped of female with bilobed swelling on surface and fold in myxal area; claw strongly recurved with striations along concave margin ( Fig. 23D ). Sternal furca with blunt tines bearing conspicuous flanges ( Fig. 23E ). Distal exopodal segment of leg 1 with 3 short plumose setae on posterior margin ( Fig. 21F ); distal spine 1 longer than other spines; spines 2 and 3 each with accessory process; seta 4 longer than spines 2 and 3, shorter than segment. Leg 2 with marginal setules on endopodal segments 2 and 3; outer spines on exopodal segments 1 and 2 aligned close to longitudinal axis of ramus. First exopodal segment of leg 3 with large recurved outer spine but lacking inner seta ( Fig. 23G ); apron with raised bifid rib-like process plus circular array of large denticles on ventral surface and corrugated adhesion pad on outer margin and adjacent dorsal surface. Leg 4 uniramous, 4-segmented; exopodal segments armed with I; I; III spines. Leg 5 comprising exopodal papilla bearing 2 setae, located adjacent to protopodal papilla bearing single seta ( Fig. 23H ). Body lengths of females 1.93 mm and 2.19 mm ; length of male 1.66 mm . Remarks. This is a distinctive but uncommon member of the Caligus confusus -group. It was originally described by Pillai (1963) , based on material of both sexes collected from an unspecified species of Caranx Lacepède, 1801 caught off Trivandrum ( India ). However, there have been no new records since the original description although it was widely cited, e.g. in reviews by Pillai (1967b , 1968 ) and in his monograph (1985). It is also interesting to note that this species has not been recorded from Taiwan , despite intensive study of Taiwanese waters by Ho & Lin (see Ho & Lin, 2004, 2007; Lin & Ho, 2007 ). In Moreton Bay C. brevicaudus was found only on Caranx ignobilis , where it attached to the gill arches, the same microhabitat as C. confusus . At 1.93 to 2.19 mm the females found in Australian waters were only half the length of the Indian specimens, reported as 4.3 mm by Pillai (1963) . Despite this marked size difference, no morphological differences were apparent.