Elasmopus coxacallus, Hughes, Lauren E., 2015

Hughes, Lauren E., 2015, Maeridae from the Indo-Pacific: Elasmopus, Leeuwinella gen. nov., Maeropsis, Pseudelasmopus and Quadrimaera (Amphipoda: Crustacea), Zootaxa 4059 (2), pp. 201-256 : 202-203

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.

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

Figures

FIGURE 1. Elasmopus coxacallus sp. nov. paratype female, 4.9 mm, habitus, AM P. 81856, Horsburgh Island, Cocos (Keeling) Islands, Indian Ocean.

FIGURE 2. Elasmopus coxacallus sp. nov. holotype male, 5 mm, AM P. 81857, Horsburgh Island, Cocos (Keeling) Islands, Indian Ocean, scales 0.1 mm.

FIGURE 3. Elasmopus coxacallus sp. nov. paratype female, 4.9 mm, AM P. 81856, Horsburgh Island, Cocos (Keeling) Islands, Indian Ocean, scales 0.1 mm.