Key to male New Caledonian talitroid amphipods

1 G1 posterior margin of carpus and propodus each with palmate lobe .............................................................................................................................. 2

—— G1 posterior margin of merus, carpus, and propodus each with palmate lobe .............................................................................................................................. 4

2 G1 parachelate. G2 propodus palm with large, recurved robust setae lining palmar margin ................................................ Talorchestia spinipalma Dana, 1852

—— G1 subchelate. G2 propodus palm without large, recurved robust setae lining palmar margin ........................................................................................................ 3

3 G2 dactylus attenuated distally ............................................................. Chroestia amoa sp. nov.

—— G2 dactylus short, recurved distally .......................... Thiorchestia caledoniana gen. et sp. nov.

4 G2 propodus with midpalmar sinus .................... Chevreuxiana antennulata (Chevreux, 1915)

—— G2 propodus without palmar sinuses ........................................................................................ 5

5 Telson with apical and marginal robust setae ........ Ignamborchestia sarasini (Chevreux, 1915)

—— Telson with apical robust setae only .......................................................................................... 6

6 G2 dactylus apically acute. Gills bilobate. Telson with 2 apical setae ......................................................................... Chiltonorchestia pusilla (Chevreux, 1915)

—— G2 dactylus recurved distally. Gills quadrilobate. Telson with 4 apical setae ........................... Chiltonorchestia starmuhlneri (Ruffo & Vesentini Paiotta, 1972)

Collections (not examined). Six males, 3 females, Isle of Pines, New Caledonia, 6–13 June 1958; 4 males, 6 females, Magenta, New Caledonia, 8, 14 October 1958; 3 males, 4 females, Nou Vata, Noumea, New Caledonia, 8 October 1958; 1 male, 1 female, Mount d’Ore, New Caledonia, 18 October 1958.

Type locality. Just north of Liku’alofa Beach Resort, Tongatapu, Tonga, 21°04'50.29"S 175°20'39.10"W.

Habitat. Under dried Turbinaria and other algae in the supralittoral zone.

Remarks. Habitat reported referred to Tonga (Lowry & Bopiah, 2013); the habitat in New Caledonia is also supralittoral, an extended black sand beach with pumice.

Distribution. Australia: Queensland: Port Douglas (Serejo, 2009). Marshall Islands: Yap; Kusaie Island (J. L. Barnard, 1960). New Caledonia: NouVata, Noumea; Isle of Pines; Magenta (Morino & Miyamoto, 1988), Thio mission, Grand Terre (this paper). Papua New Guinea: Ralum, Bismarck Archipelago (Schellenberg, 1938); Motupore Island (9°31'30"N 147°16'40"E) (Morino & Miyamoto, 1988). Philippine Islands: Ubay, Bohol (Schellenberg, 1938). Solomon Islands: Gizo (Morino & Miyamoto, 1988). Rennell Islands (Bousfield, 1970). Tonga: Tongatapu (Dana, 1852; Lowry & Bopiah, 2013).