Mallacoota chandaniae, Lowry & Springthorpe, 2005

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 : 257-260

Mallacoota chandaniae n.sp.

Figs. 17–19

Type material. HOLOTYPE, ♂ “a”, 11 mm, AM P 59021 ; 1 PARATYPE, ♂ “b”, 9.1 mm, AM P 62996 , at end of sugar loading jetty 5 km long , Lucinda, Queensland, Australia, [approx. 18°31'S 146°19'E], pylon scrapings, 7 m, Frank Hoedt , CRIMP survey, August 1999, stn A138 . 5 PARATYPES, ♂ “c”, 9.5 mm, ♀ “a” 10.8 mm, 3♀♀, AM P 59020 , Evans Landing , Weipa , Queensland, Australia, [approx. 12°35'S 141°36'E], pylon scrapings, 0.5 m, Frank Hoedt , CRIMP survey, October 1999, stn A220 .

Type locality. At end of sugar loading jetty 5 km long , Lucinda , Queensland, Australia, [approx. 18°31'S 146°19'E], pylon scrapings.

Description. Based on holotype male, AM P59021, paratype male, AM P62996 and paratype female, AM P59020.

Head. Lateral cephalic lobes broad, truncated, with anteroventral notch or slit, anteroventral corner rounded. Antenna 1 longer than antenna 2; peduncular article 1 subequal in length to article 2, with 4 or more robust setae along posterior margin; flagellum with about 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; flagellum with about 11 articles. Mandible palp article 3 rectolinear, 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 2 terminal setae.

Pereon. Gnathopod 1 coxa anteroventral corner produced, slightly rounded, posteroventral corner notch absent; merus without posterodistal spine; palm acute, convex, without posterodistal corner, defined by posterodistal robust setae.

Gnathopod 2 sexually dimorphic; subchelate; coxa posteroventral corner notch absent; merus with subquadrate posteroventral corner; carpus compressed; propodus without medial depression, with strong setal bunch, palm slightly acute, sinusoidal, sculptured, with group of anterodistal robust setae, without posterodistal robust setae, defined by posteroventral spine; dactylus apically blunt. Pereopod 5 basis posterior margin straight, posteroventral corner broadly rounded. Pereopod 6 coxa anterior lobe ventral margin slightly produced, rounded; basis posterior margin straight, posteroventral corner broadly rounded. Pereopod 7 basis posterior margin straight, posteroventral corner narrowly rounded or subquadrate.

Pleon. Epimeron 1 posteroventral corner with small acute spine. Epimera 1–2 posteroventral margin without spines above posteroventral corner. Epimeron 3 posterior margin smooth, posteroventral corner subquadrate. Urosomite 1 dorsally bicarinate. Uropod 3 rami distally truncated; 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 at least halfway along longest seta.

Female (sexually dimorphic characters). Gnathopod 2 merus with sharp posteroventral spine; carpus short; setose, convex, smooth, with sparse robust setae, defined by posterodistal robust setae, without posteroventral corner; dactylus apically acute/subacute.

Habitat. Marine; littoral; living on encrusted wharf pilings.

Etymology. Named for Chandani Appadoo, in recognition of her work on the melitid amphipods of the Indian Ocean.

Remarks. Mallacoota chandaniae is a very distinctive species. For instance no Australian species has a strictly subquadrate epimeron 3 whereas seven species outside of Australia have this characteristic. Only two species within this group, M. schellenbergi Ledoyer, 1984 and the M. subcarinata of Myers, 1985 have a deeply cleft telson similar to M. chandaniae , but neither of these has the almost transverse palm of the male gnathopod 2.

Distribution. Queensland: Weipa; Lucinda (both AM).

Australian geographic areas. Northeastern Australia.