Australian Amphipoda: Melitae

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

Elasmopus spinicarpus Berents, 1983

Elasmpus spinicarpus Berents, 1983: 121, figs 17-19.

Type material. HOLOTYPE: male, 8.5 mm AM P30212; PARATYPES: female, 5.4 mm, AM P30213; 33 specimens AM P30214.

Type locality. Casuarina Beach, Lizard Island, Great Barrier Reef (14º 40.5'S 145º 26.6'E), under stones at low tide.

Description. Based on Berents, 1983: 121, figs 17-19. 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, subequal in length to article 2, with 1 robust seta on posterior margin (distal); flagellum with 17 articles (about); accessory flagellum with 3 articles. Antenna 2 peduncular article 2 cone gland reaching at least to end of peduncular article 3; flagellum with 8 articles. Mandible palp present, well developed, article 3 strongly falcate, setose along concave medial margin, 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 not produced, 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, defined by posterodistal corner, defined by posterodistal robust setae. Gnathopod 2 sexually dimorphic (slightly); subchelate; left and right gnathopods subequal in size; coxa posteroventral corner notch absent; merus with rounded posteroventral corner, or with subquadrate posteroventral corner; carpus compressed; propodus without medial depression, setose, palm acute, convex, smooth, with sparse robust setae, defined by posterodistal robust setae, without posteroventral corner; dactylus closing along palm, reaching end of palm, apically acute/subacute. Peraeopod 5 basis posterior margin convex. Peraeopod 5 basis posteroventral corner narrowly rounded or subquadrate. Peraeopod 6 coxa anterior lobe ventral margin not produced ventrally. Peraeopod 6 basis posterior margin convex (slightly). Peraeopod 6 basis posteroventral corner narrowly rounded or subquadrate. 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 distoventral spur. Uropod 3 subequal or slightly exceeding length of 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 at least halfway along longest seta.

Habitat. Marine; living under stones near low tide mark and in association with ophiuroid: Ophiocoma scolopendrina.

Depth zone. Littoral.

Remarks. Sexual dimorphism in gnathopod 2 is not strong in this species.

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

Australian geographic areas. North-eastern Australia.

Pereon. Gnathopod 2 carpus short; convex or straight.

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'.