Australian Amphipoda: Melitae

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

Elasmopus alalo Myers, 1986

Elasmopus pseudaffinis. --J.L. Barnard, 1965: 501, figs 12-13. --Ledoyer, 1972: 219, pls 38-39. --Ledoyer, 1978: 273, fig. 29A (in part). --Berents, 1983: 118, figs 15-16. --Ledoyer, 1984: 65, fig. 30b.

Elasmopus alalo Myers, 1986: 273, figs. 4-5.

Type material. HOLOTYPE: male, 12.5 mm, AM P36955. PARATYPES: 57 specimens, AM P36956.

Type locality. Rock terrace, Utulau, Tonga.

Description. Based on Myers, 1986: 273, figs 4-5. Head lateral cephalic lobes broad, rounded, 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 or shorter than article 2, without robust setae along posterior margin; flagellum with 32 articles (about). Antenna 2 peduncular article 2 cone gland reaching at least to end of peduncular article 3; article 4 longer than article 5; flagellum with 12 articles (about). Mandible palp present, well developed, article 3 strongly falcate, setose along concave medial margin, longer than article 1, article 2 shorter than article 3, article 1 not produced, shorter than article 2.

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, straight or concave, defined by posterodistal corner. 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, without strong concentration of setae, palm acute, concave, smooth, lined with robust setae or with group of anterodistal robust setae, without posterodistal robust setae, without posteroventral corner; dactylus closing along palm, reaching end of palm, apically blunt. Peraeopod 5 basis posterior margin convex. Peraeopod 5 basis posteroventral corner broadly rounded. Peraeopod 6 coxa anterior lobe ventral margin not produced ventrally. Peraeopod 6 basis posterior margin concave (slightly). 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 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 without 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 2 apical/subapical robust setae (small), apical conical extension reaching at least halfway along longest seta.

Habitat. Marine.

Depth zone. Littoral.

Remarks. Elasmopus alalo was confused with E. pseudaffinis Schellenberg, 1938 by a number of authors (Barnard, 1965; Ledoyer, 1972; 1978; Berents, 1983 and Ledoyer, 1984). Myers (1985; 1986) discussed this problem and proposed the new species E. alalo as a solution. Among the differences between the species Myers pointed out that E. alalo is twice as big as E. pseuaffinis.

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

Extrinsic distribution. Madagascar; Maritius; Micronesia; Tonga.

Australian geographic areas. North-eastern Australia.

Pereon. Gnathopod 2 merus with subquadrate posteroventral corner; carpus short; straight, lined with robust setae, defined by posterodistal robust setae; apically acute/subacute.

Gammarus appendiculatus Say, 1818: 377.

Melita appendiculatus. --Stebbing, 1906: 428. --J.L. Barnard, 1962: 107. --J.L. Barnard, 1970: 161, fig. 101. --J.L. Barnard, 1971: 85. --Feeley & Wass, 1971: 17. --Griffiths, 1973: 286. --Griffiths, 1974a: 191. --Griffiths, 1974b: 237. --Ledoyer, 1978: 282. --Ledoyer, 1979: 86, fig. 50. --Ortiz, 1978: 8. Hirayama & Kikuchi, 1979: 67, figs 2-6.

Dulichiella appendiculata. --Karaman & Barnard, 1979: 152. --Barnard & Barnard, 1983: 668.

Description. Based on male, 10 mm, AM P60600 and female, AM P60601. Head lateral cephalic lobes broad, truncated, 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 4 or more robust setae along posterior margin; flagellum with 40 articles (at least); accessory flagellum with 6 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 10 articles (about). Mandible palp present, well developed, setose along straight medial margin, longer than article 1, article 2 shorter than article 3, article 1 produced distally, shorter than article 2, about as long as broad. Maxilla 1 inner plate with setae mainly terminal.

Pereon. Gnathopod 1 not sexually dimorphic; coxa anteroventral corner 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 nearly transverse, convex (slightly) or straight, defined by posterodistal corner, without posterodistal robust setae. Gnathopod 2 sexually dimorphic; subchelate; left and right gnathopods unequal in size; coxa posteroventral corner notch present; (larger) merus with rounded posteroventral corner; compressed; palm angle nearly transverse, straight, posterodistal tooth absent, without robust setae; dactylus apically blunt; (smaller) merus with sharp posterventral tooth; long; palm straight, without posteroventral tooth. 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 straight. Peraeopod 6 basis posteroventral corner narrowly rounded or subquadrate. Peraeopod 6 propodus not expanded posterodistally. 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 not expanded posterodistally.

Pleon. Pleonite 1 with dorsal serrations, without dorsodistal spines, not dorsally bicarinate. Pleonite 2 with dorsal serrations, without dorsodistal spines, not dorsally bicarinate. Pleonite 3 with 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 serrate, with two groups of 1-3 small dorsolateral robust setae. Urosomite 3 without dorsal robust setae. Uropod 1 peduncle with basofacial robust seta, without distoventral spur. Uropod 3 greatly exceeding uropods 1 and 2; inner ramus scale-like, much shorter than outer ramus; outer ramus long (more than 1.6 x longer than peduncle), 2-articulate. Telson cleft. Telson without robust setae on inner margins. Telson without apical robust setae, apical conical extension absent.

Habitat. Marine; living among bryozoans, sponges ascidians and algae.

Depth zone. Littoral (4.5 to 50 m).

Distribution. Queensland: Lizard Island; Yonge Reef, Great Barrier Reef (both Berents, 1983). New South Wales: Julian Rocks, Byron Bay; Mary's Rock, Cook Island; Split Solitary Island; Coff's Harbour; Boambee Creek, Sawtell; Port Stephens; off Burwood Beach; Box Head, Broken Bay; off Long Reef; Port Jackson; Botany Bay; off Wattamolla; off Wollongong; Jervis Bay; Twofold Bay (all AM). Victoria: Western Port (NMV). Tasmania: Esperance Point, D'Entrecasteaux Channel (AM). South Australia: Sanders Bank, Kangaroo Island; Spencers Gulf (Chilton, 1921).

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