Gibberosus udarus Hughes 2009, sp. nov.

Gibberosus udarus sp. nov.

(Figs 1, 2)

Type material. Holotype, female, 2.6 mm, 4 slides, AM P75499, reef crest off Coconut Beach, Lizard Island (14°41.037’S 145°28.282’E), coarse sand, sand patches between reef, 2.6 m, M. Yerman, 23 February 2005 (QLD 1619). Paratypes: 2 females, AM P71003, same station data.

Additional material examined. 2 females, AM P70983 (QLD 1619); 1 unsexed, AM P71000 (QLD 1662); 1 female, AM P75501 (QLD 1960); 2 females, AM P75500 (QLD 1999); 7 females, GCRL (SEL/LIZ 2-8).

Type locality. Coconut Beach, Lizard Island, Queensland, Australia (14°41.037’S 145°28.282’E).

Etymology. From the indigenous northern Queensland Mabuiag dialect ‘Udar’ = paddle, referring to the shape of the uropod 3 in the Megaluropidae.

Description. Based on holotype female, 2.6 mm, AM P75499.

Head. Head rostrum short; lateral cephalic lobe acute. Antennae 1–2 peduncle with robust setae. Antenna 1 peduncle article 1 shorter than article 2; flagellum with 14 articles; accessory flagellum 2-articulate. Antenna 2 peduncle article 4 subequal to article 5; flagellum with 9 articles. Upper lip anteriorly notched. Lower lip mandibular lobes with extensions directed axially. Maxilla 1 inner plate foliose, with dense row of medial setae, apicolateral extension with 2 robust setae. Maxilla 2 inner plate broader than outer plate, with many setae in facial row. Mandible accessory setal row with 8 setae; mandibular palp article 3 half the length of article 2; article 2 with 9 medial setae; article 3 with row of medial robust setae.

Pereon. Gnathopod 1 coxa ventral margin convex, minutely serrate; carpus about as long as broad; propodus proximally expanded, distally narrow. Gnathopod 2 coxa ventral margin convex, minutely serrate; merus subequal to carpus, strongly produced along posterior margin of carpus; carpus subequal to propodus, distally expanded; propodus twice as long as broad. Pereopod 3 coxa distally subacute, minutely serrate; carpus with hooded setae. Pereopod 4 coxa distally tapering, ventral margin subacute, minutely serrate; carpus with hooded setae. Pereopod 5 coxa anterodorsal lobe present.

Pleon. Pleonites 1–3 dorsally serrate. Epimera 1–3 margin minutely serrate. Epimeron 3 anteroventral corner with small acute spine. Urosomites 1–2 dorsally serrate. Uropod 1 peduncle with distoventral spine. Uropod 3 peduncle with robust setae; rami twice as long as broad, heavily setose, margin lined with many short robust setae. Telson with few dorsal robust setae, with mostly apical robust setae and with short dorsal robust setae.

Male (sexually dimorphic characters). Unknown.

Habitat. Sandy bottoms.

Remarks. Gibberosus udarus sp. nov. is placed in the genus because it has an acute lateral cephalic lobe, a 2-articulate accessory flagellum and a distoventral spine on the uropod 1 peduncle. The produced distal lobe on the merus on gnathopod 2, a characteristic of the genus Gibberosus, is present on G. udarus sp. nov. and is similar to that of G. devaneyi, but less produced than the remaining species in the genus, G. coibaensis, G. falciformis, G. longimerus and G. myersi.

In Gibberosus udarus sp. nov. and G. myersi, pleonites 1 – 2 are serrate, while in G. coibaensis, G. falciformis, G. devaneyi and G. longimerus these margins are smooth. Epimeron 3 is weakly dentate in G. udarus sp. nov. and G. falciformis, serrate in G. myersi and G. longimerus and smooth in G. devaneyi.

Distribution. Australia. Queensland: Lizard Island (current study).