Australian Amphipoda: Melitae

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

Maera hamigera Haswell, 1879

Moera hamigera Haswell, 1879b: 333, pl. 21, fig. 1.

Maera hamigera. --Stebbing, 1888: 1790. --Della Valle, 1893: 723. --Stebbing 1906: 437. --Barnard & Barnard, 1983: 623

not Maera hamigera. --Walker 1909: 335, pl. 43, fig. 5, pl. 3. --Stebbing 1910a: 600. --K.H. Barnard, 1916: 196, pl. 27, figs 11-12. --J.L. Barnard, 1965: 507, fig. 16 (in part). --Karaman & Ruffo, 1971: 152, figs 21-23. --Ledoyer, 1982: 523, figs 196-197. --Myers, 1997: 109.

Type material. SYNTYPE: male, AM P3477.

Type locality. Port Jackson, New South Wales (33º 51'S 151º 16'E).

Description. Based on male, AM P60608, and female, AM P60609. 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, subequal in length to article 2 (slightly longer), with 1 robust seta on posterior margin (distal); flagellum with 26 articles; accessory flagellum with 4 articles. Antenna 2 peduncular article 2 cone gland not reaching to end of peduncular article 3; article 4 longer than article 5 (slightly); flagellum with 9 articles. Mandible palp present, well developed, article 3 rectolinear, setose along straight medial margin, longer than article 1, article 2 longer than article 3, article 1 not produced, 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 produced, acute, 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 (slightly convex), defined by posterodistal corner, defined by posterodistal robust setae. Gnathopod 2 sexually dimorphic; subchelate; left and right gnathopods unequal in size; coxa posteroventral corner notch absent; (larger) merus with subquadrate posteroventral corner; compressed; palm angle nearly transverse, concave (kinda), defined by posterodistal tooth, with robust setae; dactylus apically blunt (apparently); (smaller) merus with sharp posterventral tooth; short, or long; palm straight, without posteroventral tooth. Peraeopod 5 basis posterior margin convex (slighlty). Peraeopod 5 basis posteroventral corner broadly rounded. Peraeopod 6 coxa anterior lobe ventral margin slightly produced, rounded, or not produced ventrally. Peraeopod 6 basis posterior margin straight. Peraeopod 6 basis posteroventral corner broadly rounded. Peraeopod 6 propodus not expanded posterodistally. Peraeopod 7 basis posterior margin convex (slighlty). Peraeopod 7 basis with posterior margin castelloserrate or 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 or serrate (minute), 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, 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 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.

Habitat. Marine; rock platforms.

Depth zone. Littoral (subtidal).

Remarks. Since Haswell (1879) described Maera hamigera from Port Jackson, only Stebbing (1910a) has reported it from Australian waters - several specimens of about 5 mm from off Wattamolla, which he unfortunately did not illustrate.

However, it has been reported by Walker (1909) from the Red Sea, K.H. Barnard (1916) from Southern Africa, J.L. Barnard (1965) from Micronesia, Karaman & Ruffo (1971) from the Mediterranean Sea, Ledoyer (1982) from Madagascar and Myers (1997) from Western Samoa. Ledoyer (1982) completely illustrated and described his material. Based on this species concept he suggested that the Maera sp. A of J.L. Barnard, 1970, is M. hamigera, extending its distribution to Hawaii and that M. mannarensis Sivaprakasam, 1970, is a synomym of M. hamigera, which extends its distribution into India.

All reports subsequent to Stebbing (1910a) must be considered as erroneous based on the redescription of M. hamigera presented here, and the distribution of the species is confined to south-eastern Australia.

Distribution. New South Wales: Coff Harbour (AM); Port Jackson (Haswell, 1879); Munganno Point, Twofold Bay (Hutchings, et al., 1989).

Australian geographic areas. South-eastern Australia.

(Variant) Female (sexually dimorphic characters).

Pereon. Gnathopod 2 left and right gnathopods subequal in size; merus with sharp posteroventral tooth; carpus short, or long; propodus without medial depression, palm acute, straight, sculptured, 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.'.