Australian Amphipoda: Melitae

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

Mallacoota balara Berents, 1983

Mallacoota balara Berents, 1983: 133, figs 25-26.

Type material. HOLOTYPE: male, 6.4 mm, AM P30133. PARATYPES: female, 6.8 mm, AM P30134: 2 specimens, AM P30135; 1 male, AM P30136; 4 specimens, AM P30137; 2 specimens, AM P30138; 1 specimen, USNM 190700; 1 specimen, USNM 190701.

Type locality. Fringing reef between Bird Islet and South Island, Lizard Island Great Barrier Reef, (14º 42'S 145º 28'E), reef rock, 12 m depth.

Description. Based on Berents, 1983: 133, figs 25-26. Antenna 1 longer than antenna 2; peduncular article 1 not geniculate with article 2, subequal in length to article 2, with 1 robust seta on posterior margin; flagellum with 21 articles; accessory flagellum with 3 articles. Antenna 2 flagellum with 8 articles. Mandible palp present, well developed, with setae mostly terminal, subequal to article 1, article 2 shorter than article 3, article 1 not produced, longer than article 2, about twice as long as broad. Maxilla 1 inner plate with setae mainly terminal.

Pereon. Gnathopod 1 not sexually dimorphic; coxa anteroventral corner produced, rounded (slightly) or not produced, coxa posteroventral corner notch present; merus without posterodistal tooth; carpus about 2 x as long as broad; propodus without anterodistal projection, posterodistal margin not swollen, palm acute, 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 subquadrate posteroventral corner; carpus compressed; propodus without medial depression, without strong concentration of setae, palm acute, sculptured, with group of anterodistal robust setae, without posterodistal robust setae, without posteroventral corner; dactylus closing along palm, reaching end of palm, apically acute/subacute. Peraeopod 5 basis posterior margin concave (slighlty). Peraeopod 5 basis posteroventral corner broadly rounded. Peraeopod 6 coxa anterior lobe ventral margin not produced ventrally. Peraeopod 6 propodus not expanded posterodistally. Peraeopod 7 basis posterior margin convex. Peraeopod 7 basis with posterior margin smooth or minutely castelloserrate, posteroventral corner broadly rounded. Peraeopod 7 propodus not expanded posterodistally.

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 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 3 inner ramus subequal in length to outer ramus; outer ramus short (shorter than or subequal to peducle), 1-articulate. Telson cleft. Telson without robust setae on inner margins. Telson each lobe with 2 apical/subapical robust setae, apical conical extension reaching scarcely one third along longest seta.

Habitat. Marine; living in coral rubble.

Depth zone. Littoral (12 m).

Distribution. Queensland: Lizard Island, Great Barrier Reef (Berents, 1983).

Australian geographic areas. North-western Australia.

(Variant) Female (sexually dimorphic characters).

Pereon. Gnathopod 2 coxa posteroventral corner notch present; carpus long; straight, smooth, without robust setae.

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.'.