Maeridae from the Indo-Pacific: Elasmopus, Leeuwinella gen. nov., Maeropsis, Pseudelasmopus and Quadrimaera (Amphipoda: Crustacea) Author Hughes, Lauren E. text Zootaxa 2015 4059 2 201 256 journal article 39226 10.11646/zootaxa.4059.2.1 7dbcc655-553b-4d35-8562-1a98c4555b89 1175-5326 232164 F9ED6784-D8C0-409E-9E4F-73879B265BC4 Elasmopus coxacallus sp. nov. ( Figs 1–3 ) Type material. Holotype male, 4.9 mm , dissected, 4 slides, AM P.81856, dive site ‘Winter Wall’, near Horsburgh Island , Cocos (Keeling) Islands , 12°05'15"S , 96°50'14"E , 9.5 m , rubble under plate coral, 12 October 2008 , coll. K.B. Attwood, MI WA 835. Paratype female, 5 mm , dissected, 4 slides, AM P.81857, dive site ‘Winter Wall’, near Horsburgh Island , Cocos (Keeling) Islands , 12°05'15"S , 96°50'14"E , 9 m , rubble, 12 October 2008 , coll. K.B. Attwood, MI WA 834. Type locality. Near Horsburgh Island , Cocos (Keeling) Islands , Indian Ocean 12°05'15"S , 96°50'14"E . Etymology. Derived from the Greek ‘kallus’, meaning beauty, for the coxa 7 which has a distinctive castelloserrate posterior margin. FIGURE 1. Elasmopus coxacallus sp. nov. paratype female, 4.9 mm, habitus, AM P.81856, Horsburgh Island, Cocos (Keeling) Islands, Indian Ocean. Description. Of holotype male, 4.9 mm , AM P.81856. Head. Eyes ovate; lateral cephalic lobe broad, truncated, apically rounded, anteroventral margin with notch/ slit, corner rounded. Antenna 1 longer than antenna 2; peduncular article 1 shorter than article 2, without robust setae along posterior margin ; peduncular article 2 longer than article 3; flagellum articles as long as broad, with 12 articles; accessory flagellum minute, 3-articulate. Antenna 2 peduncular article 2 cone gland reaching end of peduncular article 3; peduncular article 4 subequal to article 5; flagellum with 8 articles. Mandible incisor cuspidate; accessory setal row with 4 setae; molar well-developed, triturative; palp well-developed, 3-articulate; article 1 twice as long as broad, shorter than article 2; article 2 longer than article 3 with many slender setae; article 3 strongly falcate, short, 2.1 as long as broad, longer than article 1, with apical setae and a comb of short robust setae along anterodistal margin. Lower lip inner lobes present, outer lobes with 1 pair of ducts , mandibular lobes apically subacute. Maxilla 1 inner plate subquadrate, with 2 apical plumose setae. Maxilliped palp propodus with small distomedial flap. Pereon . Gnathopod 1 coxa anterior margin straight, anteroventral corner produced, rounded; merus without posterodistal tooth; carpus 1.5 as long as broad, shorter than propodus, length 1.1 propodus, with long slender setae covering surface ; propodus medial surface setal comb absent , palm subacute, convex, entire, lined with robust setae, defined by posterodistal corner with 1 long robust seta . Gnathopod 2 sexually dimorphic; subchelate; basis slender, anterodistal corner subquadrate; merus with subquadrate distoventral corner; carpus compressed, lobate, projecting between merus and propodus, length 0.9 breadth; propodus expanded, with