Distribution & Ecology: Society (Moorea, Raiatea, Tahiti) - Freshwater.

Regional Records: Sesarma trapezoidea - Guérin-Méneville, 1838: 14 (Tahiti). - Seurat, 1934: 51 (Tahiti). - Forest & Guinot, 1962: 72 (Biogeography "Tahiti-Tuamotu"). - Marquet, 1988: 90, fig. 48, tab. 23; 1991: 133, tab. 1-2; 1993: tab. 1, 3 (Moorea, Tahiti). - Sesarma (Sesarma) trapezoidea - Nobili, 1907: 405 (Tahiti). - Edmonson, 1951: 237, fig. 33b (Raiatea, Tahiti). - Forest & Guinot, 1961: 157, fig. 164a-b, 165 (Tahiti; mountain, 500m). - Sesarma (Sesarma) trapezoideum - Rathbun, 1907: 33 (Tahiti). - Labuanium trapezoideum - Serène & Soh, 1970: 402, 406 (Syn.). - Guinot, 1985: 454 (List). - Poupin, 1996a: 70, 76 (Checklist). - Keith et al., 2002: 66, photograph (Atlas: Raiatea). - Unpublished record, coll. Robert Vecella, Putua, Papenoo river, Tahiti, photographs and specimens deposited in CRIOBE/Moorea collection, det. J. Poupin from photograph only. - Remark: Labuanium rotundatum (Hess, 1865) is also recorded in Polynesia by Sakai (1976: 663; distribution only "Micronesia, Polynesia"; cited afterwards by Guinot, 1985: 454). Sakai must consider the Polynesia s.l., with about 10 states, including French Polynesia. It is doubtful that this species have been really collected in French Polynesia since we have not find any mention of it in Tesch (1917: 193), who gives a detailed distribution, or in Serène & Soh (1970: 402, 406), when they have established the genus Labuanium. For the moment, it thus seems better to exclude it from the area.