Australian Amphipoda: Melitae

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

Mallacoota kameruka Lowry & Springthorpe

Elasmopus subcarinatus. --Stebbing, 1888: 1019, pl. 98.

? Mallacoota subcarinata. --Chilton, 1921: 76 (These specimens (AM E5352 and E5356) were collected from eastern Bass Strait and Tasmania in depths similar to Stebbing's, 1888 material).

Mallacoota subcarinata. --J.L. Barnard, 1972a: 247, fig. 145. --Barnard & Barnard, 1983: 632 (in part).

Type material. HOLOTYPE: male "a", 10.0 mm, AM P60491. PARATYPES: male "b", AM P60494; female, 10.0 mm, AM P60492; 5 males, 5 females, AM P60493.

Type locality. Mary's Rock, Cook Island, New South Wales (28º11.42'S 153º34.79'E), on a bryozoan, 19 m.

Description. Based on holotype male, AM P60491 and paratype female, AM P60492. 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 24 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 subequal to article 5; flagellum with 11 articles (about). Mandible palp present, well developed, article 3 cone-like, with setae mostly terminal, longer than article 1, article 2 shorter than 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, without 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 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 convex. Peraeopod 5 basis posteroventral corner narrowly rounded or subquadrate. Peraeopod 6 coxa anterior lobe ventral margin slightly produced, rounded. Peraeopod 6 basis posterior margin convex. Peraeopod 6 basis posteroventral corner broadly rounded. 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 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; living among bryozoans and red algae.

Depth zone. Littoral (16 to 19 m).

Remarks. This species was originally described as Mallacoota subcarinata phenotype B by J.L. Barnard (1972a). It appears to be the same as the Challenger specimens Stebbing (1888) described from off Melbourne. Mallacoota kameruka is similar to M. subcarinata and M. malua in the absence of posterovental notches on coxae 1 and 2. It differs from all Australian species in having convex posterior margins of peraeopods 5 to 7.

Distribution. Queensland: Port Denison (AM). New South Wales: Mary's Rock, Cook Island; Julian Rocks, Byron Bay; Port Stephens; Port Jackson; Jervis Bay (all AM). Victoria: Off Melbourne (Stebbing, 1888); Port Phillip (J.L. Barnard, 1972a). Western Australia. Point Peron; Rottnest Island; Cottesloe Beach (all J.L. Barnard, 1972a); Warnbro Sound (AM).

Extrinsic distribution. ? Fiji.

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

(Variant) Female (sexually dimorphic characters).

Pereon. Gnathopod 2 carpus short; setose, smooth, with sparse robust setae, defined by posterodistal robust setae, defined by posteroventral corner; apically acute/subacute.

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.'.