Mallacoota malua, Lowry & Springthorpe, 2005

Lowry, JK & Springthorpe, RT, 2005, New and Little-known Melitid Amphipods from Australian Waters (Crustacea: Amphipoda: Melitidae), Records of the Australian Museum 57, pp. 237-302 : 265-267

Mallacoota malua n.sp.

Figs. 26–28

Type material. HOLOTYPE, ♂ “a”, 10 mm, AM P56679 ; 10 PARATYPES, 3♂♂, 7♀♀, AM P60485 ; Coffs Harbour Jetty, Coffs Harbour , New South Wales, 30°18.4'S 153°08.5'E, arborescent sponge on jetty pilings, 7 m, S.J. Keable, 9 March 1992, stn NSW-735; 22 PARATYPES, 8♂♂, 14♀♀, AM P56678 , type locality, Pyura praeputialis on jetty pilings, 8 m, P.B. Berents & S.J. Keable, 9 March 1992, stn NSW 733 ; 1 PARATYPE, ♀, 8.5 mm, AM P60486 ; 1 PARATYPE, ♂ “c”, 7.1 mm, AM P60490 , type locality, coral scrapings on jetty pilings, 6 m, R.T. Springthorpe, 9 March 1992, stn NSW 726 .

Additional material examined. New South Wales: 1♂, 2♀♀, AM P56674, 50 m west of Split Solitary Island, 30°14.0'S 153°10.8'E, Herdmania momus , rocks, sponges & ascidians, 15–17 m, P.A. Hutchings & C.L. Rose, 7 March 1992, stn NSW-677. 1♀, AM P56676, Boambee Creek, Sawtell, 30°20.8'S 153°05.6'E, silty sand submerged at low tide, 0.3 m, E. Albertson & S. Keable, 8 March 1992, stn NSW-714. 4♂♂, 12♀♀, AM P57220, Coffs Harbour Jetty, Coffs Harbour, 30°18.4'S 153°08.5'E, worm tubes encrusted with sponge on jetty pilings, 6 m, R.T. Springthorpe, 9 March 1992, stn NSW-725. 1 specimen, AM P57221, same locality, coral scrapings on jetty pilings, 6 m, R.T. Springthorpe, 9 March 1992, stn NSW-738. 5♂♂, 6♀♀, AM P57301, same locality, finger sponge on jetty pilings, 4 m, R.T. Springthorpe, 9 March 1992, stn NSW-734. 1♂, 4♀♀, AM P57302, same locality, coral scrapings on jetty pilings, 6 m, R.T. Springthorpe, 9 March 1992, NSW 726. 7♀♀, AM P58230, outer end of Kurnell Pier, Botany Bay, 34°00.2'S 151°12.5'E, pylon scrapings, 7 m, NSW Fisheries/CRIMP Survey, 21 October 1998, stn BB KP1 P1–7. 1♂ (“b”), AM P60487, same locality. 2♂♂, 1♀, AM P63071, same locality, pylon scrapings, 3 m, NSW Fisheries/CRIMP Survey, 21 October 1998, BB KP1 P2–3. 1♂, AM P58231, Kurnell Pier (near shoreline), Botany Bay, 34°00.5'S 151°12.7'E, pylon scrapings, 3 m, NSW Fisheries/CRIMP Survey, 21 October 1998, stn BB KP2 P3–3. 2♂♂, 1♀, AM P60488, north east corner of Clark Island, Port Jackson, 33°51.85'S 151°14.47'E, red alga, 2 m, I. Takeuchi & D. Bray, 17 April 1996, stn NSW-1250. 6♂♂, 5♀♀, AM P60623, Port Jackson, 33°51'S 151°16'E, [AM Old Collection].

Type locality. Coffs Harbour Jetty, New South Wales, Australia, 30°18.4'S 153°08.5'E, sponges, ascidians on pilings, 7 m.

Description. Based on holotype male “a”, AM P56679, paratype female, AM P60486, paratype male “c”, AM P60490 and male “b”, AM P60487.

Head. Lateral cephalic lobes broad, truncated, with anteroventral notch or slit, anteroventral corner rounded. Antenna 1 longer than antenna 2; peduncular article 1 subequal in length to article 2, with 3 robust setae along posterior margin; flagellum with at least 23 articles; accessory flagellum with 3–4 articles. Antenna 2 peduncular article 2 cone gland reaching at least to end of peduncular article 3; article 4 longer than article 5, or article 4 subequal to article 5; flagellum with about 12 articles. Mandible palp article 3 rectolinear, with setae mostly terminal, longer than article 1; article 2 subequal to article 3; article 1 not produced, shorter than article 2, about twice as long as broad. Maxilla 1 inner plate with about 4 setae mainly terminal.

Pereon. Gnathopod 1 coxa anteroventral corner produced, rounded, posteroventral corner notch absent; merus without posterodistal spine; propodus palm acute, convex or straight, defined by posterodistal corner, defined by posterodistal robust setae. Gnathopod 2 sexually dimorphic; subchelate; coxa posteroventral corner notch absent; merus with sharp posteroventral spine; carpus compressed; propodus without medial depression, with strong setal bunch, palm acute, straight, sculptured, with sparse robust setae and with group of anterodistal robust setae, without posterodistal robust setae, defined by posteroventral spine; dactylus apically falcate. Pereopod 5 basis posterior margin slightly concave, posteroventral corner narrowly rounded or subquadrate. Pereopod 6 coxa anterior lobe ventral margin slightly produced, rounded; basis posterior margin slightly concave or straight, posteroventral corner narrowly rounded or subquadrate; propodus expanded posterodistally to from a hood-like projection. Pereopod 7 basis posterior margin straight, with posterior margin smooth or minutely castelloserrate, posteroventral corner narrowly rounded or subquadrate; propodus expanded posterodistally to from a hood-like projection.

Pleon. Epimeron 1 posteroventral corner with small acute spine. Epimera 1–2 posteroventral margin without spines above posteroventral corner. Epimeron 3 posterior margin smooth, posteroventral corner subquadrate or with small acute spine. Urosomite 1 dorsally bicarinate. Uropod 3 inner ramus subequal in length to outer ramus; outer ramus longer (1.2 to 2× length) than peduncle, 1-articulate. Telson each lobe with 3 or more apical/subapical robust setae, apical conical extension absent.

Female (sexually dimorphic characters). Gnathopod 2 carpus short; propodus setose, slightly convex, smooth, with sparse robust setae, defined by posterodistal robust setae, without posteroventral corner; dactylus apically acute/ subacute.

Habitat. Marine; littoral; among ascidians, sponges and red algae on wharf pilings, 0 to 17 m depth.

Etymology. Named for the wooden steamer Malua , built in Botany Bay and sunk at the mouth of Port Hacking, New South Wales, in 1886.

Remarks. Mallacoota malua is most closely related to Mallacoota kameruka . They differ in the shape of the bases of pereopods 5–7, and in the sculpturing on the palm of gnathopod 2. Mallacoota malua is the only species with posterodistal hood-like projections on pereopods 6 and 7.

Distribution. New South Wales: Split Solitary Island; Coffs Harbour; Boambee Creek, Sawtell; Clark Island, Port Jackson; Kurnell, Botany Bay (all AM).

Australian geographic areas. Southeastern Australia.