Australian Amphipoda: Melitae

J.K. Lowry, P.B Berents & R.T. Springthorpe

Mallacoota malua Lowry & Springthorpe

Type material. HOLOTYPE: male"a", 10 mm, AM P56679. PARATYPES: 8 males, 14 females, AM P56678; 3 males, 7 females, AM P60485; female, 8.5 mm, AM P60486; male"c", 7.1 mm, AM P60490.

Type locality. Coffs Harbour Jetty, New South Wales (30º18.4'S 153º08.5'E), sponges on pilings.

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 not geniculate with article 2, subequal in length to article 2, with 3 robust setae along posterior margin; flagellum with 23 articles (plus); 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 12 articles (about). Mandible palp present, well developed, article 3 cone-like, 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 setae mainly terminal (about 3).

Pereon. Gnathopod 1 not sexually dimorphic; coxa anteroventral corner produced, rounded, coxa posteroventral corner notch absent; merus without posterodistal tooth; carpus about 2 x as long as broad; propodus without anterodistal projection, posterodistal margin not swollen, palm acute, convex or straight, defined by posterodistal corner, defined by posterodistal robust setae. Gnathopod 2 sexually dimorphic; subchelate; left and right gnathopods subequal in size; coxa posteroventral corner notch absent; merus with sharp posteroventral tooth; carpus compressed; propodus without medial depression, with strong setal bunch, palm acute, straight, sculptured, with sparse robust setae or with group of anterodistal robust setae, without posterodistal robust setae, defined by posteroventral tooth; dactylus closing along palm, reaching end of palm, apically falcate. Peraeopod 5 basis posterior margin concave (slightly). Peraeopod 5 basis posteroventral corner narrowly rounded or subquadrate. Peraeopod 6 coxa anterior lobe ventral margin slightly produced, rounded. Peraeopod 6 basis posterior margin concave (slightly), or straight. Peraeopod 6 basis posteroventral corner narrowly rounded or subquadrate. Peraeopod 6 propodus expanded posterodistally to from a hood-like projecton. Peraeopod 7 basis posterior margin straight. Peraeopod 7 basis with posterior margin smooth or minutely castelloserrate, posteroventral corner narrowly rounded or subquadrate. Peraeopod 7 propodus expanded posterodistally to from a hood-like projecton.

Pleon. Pleonite 1 without dorsal serrations, without dorsodistal spines, not dorsally bicarinate. Pleonite 2 without dorsal serrations, without dorsodistal spines, not dorsally bicarinate. Pleonite 3 without dorsal serrations, without dorsodistal spines, dorsally smooth. Epimeron 1 anteroventral corner without curved spine. Epimera 1-2 posteroventral margin without spines above posteroventral corner. Epimeron 3 posterior margin smooth, posteroventral corner subquadrate or with small acute spine, posteroventral margin smooth. Urosomite 1 without dorsal carina, without a small dorsal hump, without dorsal serrations, without spines or gape, dorsally bicarinate. Urosomite 1 without posterodorsal spine. Urosomite 2 posterior margin smooth, without dorsolateral robust setae. Urosomite 3 without dorsal robust setae. Uropod 1 peduncle with basofacial robust seta, without distoventral spur. Uropod 3 subequal or slightly exceeding length of uropods 1 and 2; inner ramus subequal in length to outer ramus; outer ramus medium length (1.1 to about 1.5 x longer than peducle), 1-articulate. Telson cleft. Telson without robust setae on inner margins. Telson each lobe with 3 or more apical/subapical robust setae, apical conical extension absent.

Habitat. Marine; among ascidians, sponges and red algae on rocks and wharf pilings.

Depth zone. Littoral (0.3 to 17 m).

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

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

Extrinsic distribution. ? Fiji.

Australian geographic areas. South-eastern Australia, or South-western Australia.

Description. Based on holotype male, AM P56679, paratype female, AM P60486 and paratype male, AM P60490.

Pereon. Gnathopod 2 carpus short; setose, convex (slightly), smooth, with sparse robust setae, defined by posterodistal robust setae, without posteroventral corner; apically acute/subacute.

Pleon. Habitat. among ascidians, sponges and red algae on wharf pilings.

Australian geographic areas. South-eastern Australia.

Cite this publication as: 'J.K. Lowry, P.B Berents & R.T. Springthorpe (2000 onwards). Australian Amphipoda: Melitae Descriptions, Illustrations, Identification and Information Retrieval. Version: 2 October 2000. https://crustacea.net'.