Australian Amphipoda: Melitae

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

Mallacoota subcarinata (Haswell, 1879)

Megamoera sub-carinata Haswell, 1879b: 335, pl. 21, fig. 4.

Elasmopus subcarinatus. --Stebbing, 1906: 441. --Stebbing, 1910a: 602. --Chilton, 1921: 76.

not Megamoera sub-carinata. --Chilton, 1885: 1039.

not Moera petriei Thomson, 1882: 236, pl. 18, fig. 3. --Chilton, 1883: 82, pl. 2, fig. 4. --Chilton, 1885: 1039.

not Moera subcarinata. --Chilton, 1885: 1039. --Thomson, 1889: 261.

not Moera sub-carinata. --Chilton, 1884: 230. --Thomson & Chilton, 1886: 146.

not Elasmopus subcarinatus. --Stebbing, 1888: 1019, pl. 98 (plate labelled as E. persetosus). --Chilton, 1892: 261. --Walker, 1904: 275, pl. 5, fig. 34. --Stebbing, 1906: 441. --Walker, 1909: 335. --Stebbing, 1910a: 602. --Stebbing, 1910b: 457. --Thomson, 1913: 243. --Chilton, 1915: 321, figs 1-6. --Chilton, 1921: 76. --Stephensen, 1931: 11. --K.H. Barnard, 1935: 286. --Pirlot, 1936: 317, figs 136-145. --K.H. Barnard, 1937: 160.

not Maera subcarinata. --K.H. Barnard, 1940: 460. --Nayar, 1967: 149.

not Mallacoota subcarinata. --J.L. Barnard, 1972a: 247, figs 144-145. --J.L. Barnard, 1972b: 114, figs 59-60. --Ledoyer, 1978:281, fig. 32. --Barnard & Barnard, 1983: 632. --Myers, 1985: 121, fig. 96.

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Type material. SYNTYPES (probable): male, 9.6 mm, and female, 10.4 mm, AM G5390, (Old Collection, labelled as type by A.R. McCulloch, 1905); P3492, 3 specimens, Port Stephens, New South Wales (32°42'S 152°06'E) (Old Collection, specimens not located, March 1993).

Type locality. Port Jackson, New South Wales (33º51'S 151º16'E) and Port Stephens, New South Wales (32°42'S 152°06'E).

Description. Based on male and female syntypes, AM G5390, male "a", AM P22487 and male "b", AM P60563. 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 1 robust seta on posterior margin or with 2 robust setae along posterior margin or with 3 robust setae along posterior margin; flagellum with 31 articles (about); accessory flagellum with 5 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 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.

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 extremely acute, convex or sinusoidal, sculptured, with group of anterodistal robust setae, without posterodistal robust setae, without posteroventral corner; dactylus closing along palm, reaching end of palm, apically blunt or apically falcate. Peraeopod 5 basis posterior margin straight. 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. Peraeopod 6 basis posteroventral corner serrate. Peraeopod 6 propodus not expanded posterodistally. Peraeopod 7 basis posterior margin concave, or straight. Peraeopod 7 basis with posterior margin smooth or minutely 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 without spines above posteroventral corner. Epimeron 3 posterior margin smooth, posteroventral corner with strongly produced 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 reaching scarcely one third along longest seta or absent.

Habitat. Marine; subtidal rock platform, sand, mud, sponges and from jetty pilings.

Depth zone. Littoral, or Continental shelf (3.5 to 108 m).

Remarks. Mallacoota subcarinata Haswell, 1879 appears to be confined to Australian waters. All extrinsic records need to be carefully studied. The species appears to be most similar to those species with a strong posteroventral corner spine on epimeron 3. In Australian waters this includes M. diemenensis and Mallacoota euroka. Mallacoota diemenensis differs from all other Australian species in having dorsal cainae on pleonites 1 to 3. Mallacoota subcarinata differs from Mallacoota sp A in having only one to three robust setae along the posterior margin of antennal pedunclular article 1 and in the posterior margin of the basis of peraeopod 7 which is straight in M. subcarinata and convex in M. euroka.

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Distribution. New South Wales: east of Long Reef; east of Port Jackson (both AM); Port Jackson (Haswell, 1879b); off Botany Bay; off Jibbon; off Wattamolla; off Wollongong (all Stebbing, 1910a); Jervis Bay (AM); Munganno Point, Twofold Bay (Hutchings et al). Tasmania: Bass Strait (Chilton, 1921).

Australian geographic areas. South-eastern Australia.

Megamoera sub-carinata Haswell, 1879x: 335, pl. 21, fig. 4. --Chilton, 1885: 1039.

Elasmopus subcarinatus. --Stebbing, 1910a: 602.

not Moera sub-carinata. --Chilton, 1884: 230. --Thomson & Chilton, 1886: 146.

not Moera subcarinata. --Chilton, 1885: 1039. --Thomson, 1889: 261.

not Elasmopus subcarinatus. --Stebbing, 1888: 1019 pl. 98. --Chilton, 1892: 261. --Walker, 1904: 275, pl. 5, fig. 34. --Stebbing, 1906: 441. --Walker, 1909: 335. --Stebbing, 1910b: 457. --Thomson, 1913: 243. --Chilton, 1915: 321, figs 1-6. --Chilton, 1921: 76. --Stephensen, 1931: 11. --K.H. Barnard, 1935: 286. --Pirlot, 1936: 317, figs 136-145. --K.H. Barnard, 1937: 160.

not Maera subcarinata. --K.H. Barnard, 1940: 460. --Nayar, 1967: 149.

not Mallacoota subcarinata. --J.L. Barnard, 1972a: 247, figs 144-145. --J.L. Barnard, 1972b: 114, figs 59-60. --Ledoyer, 1978: 281, fig. 32. --Barnard & Barnard, 1983: 632. --Myers, 1985: 121, fig. 96

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Pereon. Gnathopod 2 carpus short; setose, convex, smooth, without robust setae; apically acute/subacute.

Pleon. Remarks. Mallacoota subcarinata Haswell, 1879 appears to be confined to Australian waters. All extrinsic records need to be carefully studied. The species appears to be most similar to those species with a strong posteroventral corner spine on epimeron 3. In Australian waters this includes M. diemenensis and Mallacoota euroka. Mallacoota diemenensis differs from all other Australian species in having dorsal cainae on pleonites 1 to 3. Mallacoota subcarinata differs from Mallacoota sp A in having only one to three robust setae along the posterior margin of antennal pedunclular article 1 and in the posterior margin of the basis of peraeopod 7 which is straight in M. subcarinata and convex in M. euroka.

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'.