Australian Amphipoda: Melitae

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

Maera mastersi (Haswell, 1879)

Megamaera mastersi Haswell, 1879a: 265, pl. 11, fig. 1. --Haswell, 1882: 258. --Haswell, 1885: 105.

? Megamaera thomsoni Miers, 1884: 318, pl. 34, fig. B.

Maera mastersii. --Stebbing, 1899: 426. --Stebbing, 1906: 439. --Stebbing, 1910a: 642. --Chilton, 1916: 367. --Chilton, 1921: 72. --Chilton, 1925: 317. --Hurley, 1954: 603.

? Moera mastersii. --Chilton, 1911: 564.

Maera mastersi. --Thomson, 1882: 235 (in part, part = M. quadrimana). --Sheard, 1936: 177, fig. 3. --Sheard, 1937: 24. --J.L. Barnard, 1972a: 226, fig. 132. --J.L. Barnard, 1972b: 109, figs 55-56. --Lowry & Fenwick, 1983: 236.

not Maera mastersii. --Chevreux, 1908: 481. --Stebbing, 1910b: 457. --J.L. Barnard, 1962: 99.

Type material. SYNTYPE (probable): 1 specimen AM P3487 (Old Collection, labelled as type by K. Sheard, 1939).

Type locality. Port Jackson, New South Wales (33º51'S 151º16'E).

Description. Based on one male, AM P60620 and one female, AM P60621. Head lateral cephalic lobes broad, rounded, with anteroventral notch or slit, anteroventral corner subquadrate. Antenna 1 longer than antenna 2; peduncular article 1 not geniculate with article 2, shorter than article 2, with 1 robust seta on posterior margin (distal); flagellum with 26 articles; accessory flagellum with 6-7 articles. Antenna 2 peduncular article 2 cone gland not reaching to end of peduncular article 3; article 4 longer than article 5; flagellum with 16 articles. Mandible palp present, well developed, article 3 rectolinear, with setae mostly terminal, longer than article 1, article 2 longer than article 3, article 1 not produced, shorter than article 2, about as long as broad.

Pereon. Gnathopod 1 not sexually dimorphic; coxa anteroventral corner produced, acute; merus with sharp 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 unequal in size; (larger) merus with sharp posterventral tooth; short; palm angle acute, concave, defined by posterodistal tooth, with robust setae; dactylus apically acute; (smaller) merus with sharp posterventral tooth; short; palm concave (slightly), defined by posteroventral tooth. Peraeopod 5 basis posterior margin concave (slighlty), or straight. Peraeopod 5 basis posteroventral corner narrowly rounded or subquadrate, or serrate. Peraeopod 6 coxa anterior lobe ventral margin slightly produced, rounded. Peraeopod 6 basis posterior margin concave (slighlty), or straight. Peraeopod 6 basis posteroventral corner narrowly rounded or subquadrate. Peraeopod 6 propodus not expanded posterodistally. Peraeopod 7 basis posterior margin straight, or convex (slighlty). Peraeopod 7 basis with posterior margin castelloserrate, posteroventral corner narrowly rounded or subquadrate. 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 with 1 to 2 large or small spines above spine defining posteroventral corner. Epimeron 3 posterior margin serrate, 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, not 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 exceeding uropods 1 and 2; inner ramus subequal in length to outer ramus; outer ramus long (more than 1.6 x longer than peduncle), 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 reaching scarcely one third along longest seta.

Habitat. Marine; subtidal rocky shore, sea grasses, shelly sand, mud.

Depth zone. Littoral, or Continental shelf (0 to 85 m).

Remarks. J.L. Barnard (1972a) documented a number of differences between the Australian and New Zealand populations. In his opinion the New Zealand population might be an undescribed species.

Distribution. New South Wales: Split Solitary Island; Sow and Pigs, Port Jackson (both AM); Port Jackson (Haswell, 1879); Clovelly; Little Bay; Botany Bay (all AM). Victoria: Port Phillip Bay (J.L. Barnard, 1972a); Seal Islands (AM). Tasmania: King Island; eastern slope of Bass Strait (both AM). South Australia: west of Kingston; Kangaroo Island (both Chilton, 1921); Port Davis Creek, Spencer Gulf (AM). Western Australia: Bunbury; Favourite Islands; Point Peron (all J.L. Barnard, 1972a).

Extrinsic distribution. ? New Zealand.

Australian geographic areas. South-eastern Australia to Southern Australia to South-western Australia.

Pereon. Gnathopod 2 left and right gnathopods subequal in size; merus with sharp posteroventral tooth; carpus short; propodus without medial depression, palm acute, straight, sculptured, lined with robust setae, defined by posterodistal robust setae, defined by posteroventral tooth; apically acute/subacute.

Pleon. Distribution. New South Wales: Split Solitary Island; Sow and Pigs, Port Jackson (both AM); Port Jackson (Haswell, 1879); Clovelly; Little Bay; Botany Bay (all AM). Victoria: Port Phillip Bay (J.L. Barnard, 1972a); Seal Islands (AM). Tasmania: King Island; eastern slope of Bass Strait (both AM). South Australia: west of Kingston; Kangaroo Island (both Chilton, 1921); Port Davis Creek, Spencer Gulf (AM). Western Australia: Bunbury; Favourite Islands; Point Peron (all J.L. Barnard, 1972a).

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'.