Linguimaera hamigera (Haswell)

Lowry, JK & Springthorpe, RT, 2005, New and Little-known Melitid Amphipods from Australian Waters (Crustacea: Amphipoda: Melitidae), Records of the Australian Museum 57, pp. 237-302 : 249-252

Linguimaera hamigera (Haswell)

Figs. 11–13

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.–Chilton, 1921b: 73.–J.L. Barnard, 1965: 507, fig. 16 (in part).–Karaman & Ruffo, 1971: 152, figs 21–23.–Ledoyer, 1982: 523, figs 196–197.–Karaman, 1982: 312, fig. 211.– Lyons & Myers, 1993: 587, fig. 10.–Myers, 1997: 109.

Type material. Syntype, ♂, AM P3477 , Port Jackson, New South Wales , Australia , [approx. 33°51'S 151°16'E], [AM Old Collection].

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

Additional material examined. New South Wales: 1 specimen, AM P57328, 100 m north west of Split Solitary Island, 30°14.0'S 153°10.8'E, sponge, 15–17 m, R.T. Springthorpe, 7 March 1992, stn NSW-683. 1 specimen, AM P57329, 50 m west of Split Solitary Island, 30°14.0'S 153°10.8'E, rocks with brown & red algae (coralline & Halimeda sp. ), 15–17 m, P. Hutchings & C. Rose, 7 March 1992, stn NSW-692. 1 specimen, AM P56712, Coffs Harbour Jetty, Coffs Harbour, 30°18.4'S 153°08.5'E, arborescent sponge on jetty pilings, 7 m, S.J. Keable, 9 March 1992, stn NSW-735. 1 specimen, AM P25467, 5.5–6.5 km off Wattamolla, 34°10'S 151°11'E, mud, 99–108 m, E.R. Waite on HMCS Thetis , 22 March 1898, stn 57. 1♂, AM P60608, Munganno Point, Twofold Bay, 37°06.2'S 149°55.7'E, subtidal rock platform, wharf pile, S.J. Keable & E.A. Bamber, 12 December 1984, stn M2,3. 1♀, AM P60609, same locality. Tasmania: 1 specimen, E6546, eastern slope of Bass Strait, [approx. 39°00'S 148°40'E], FIS Endeavour, 1909–1914. 1 specimen, AM P25468, same locality.

Description. Based on syntype, ♂, AM P3477, ♂, 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 slightly longer than or subequal in length to article 2, with 1 robust seta on posterior distal margin; 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 slightly longer than article 5; flagellum with 9 articles. Mandible palp 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 coxa anteroventral corner produced, acute, posteroventral corner notch absent; merus without posterodistal spine; propodus palm acute, 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; carpus compressed; propodus palm angle nearly transverse, concave, defined by posterodistal spine, with robust setae; dactylus apically blunt; (smaller) merus with sharp posteroventral spine; carpus short, or long; propodus palm straight, without posteroventral spine. Pereopod 5 basis posterior margin slightly convex, posteroventral corner broadly rounded. Pereopod 6 coxa anterior lobe ventral margin slightly produced, rounded, or not produced ventrally; basis posterior margin straight, posteroventral corner broadly rounded. Pereopod 7 basis posterior margin slightly convex, with posterior margin smooth or minutely castelloserrate, posteroventral corner broadly rounded.

Pleon. Epimeron 1 posteroventral corner broadly rounded. Epimera 1–2 posteroventral margin without spines above posteroventral corner. Epimeron 3 posterior margin smooth or minutely serrate, posteroventral corner with strongly produced acute spine. Uropod 3 inner ramus subequal in length to outer ramus; outer ramus longer (1.2 to 2× length) than peduncle, 1-articulate. Telson each lobe with 3 or more apical/subapical robust setae, apical conical extension reaching scarcely one third along longest seta.

Female (sexually dimorphic characters). Gnathopod 2 merus with sharp posteroventral spine; 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; dactylus apically acute/subacute.

Habitat. Marine; littoral; subtidal rock platforms, 0 to 7 m depth.

Remarks. Since Haswell (1879b) described Linguimaera hamigera (as Maera hamigera ) from Port Jackson, only Stebbing (1910a) has reported it from Australian waters— several specimens of about 5 mm length 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, Myers (1997) from Western Samoa and Ledoyer (1982) from Madagascar. 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 also L. hamigera , extending its distribution to Hawaii and that L. mannarensis (Sivaprakasam, 1970) is a synonym of L. hamigera , thus extending its distribution into India, a proposition not accepted by Krapp-Schickel (2003).

All reports subsequent to Stebbing (1910a) must be considered as erroneous. As currently known, A. hamigera is confined to southeastern Australia. Illustrated species in the literature (Walker, 1909; K.H. Barnard, 1916; J.L. Barnard, 1965; Karaman & Ruffo, 1971; Ledoyer, 1982) refer to one or more unnamed species. For instance Karaman & Ruffo (1971) illustrated a cleft telson without setae on the inner margins, whereas Ledoyer’s (1982) specimens have well-developed robust setae along the inner margins.

Linguimaera hamigera is most similar to L. boecki , but easily distinguished from that species by its cleft telson.

Distribution. New South Wales: Coffs Harbour (AM); Port Jackson (Haswell, 1879b); Munganno Point, Twofold Bay (AM). Tasmania: eastern slope of Bass Strait.

Australian geographic areas. Southeastern Australia.