36 K.L. Lamprell, J. Stanisic 
(approx. 80) flattened, concentric ribs which anastomose laterally and with irregular growth pauses; 
interstices between ribs very narrow, moderately deep. Periostracum white, thick and mostly confined. 
to the margins. Hinge of left valve with anterior lateral tooth round and raised; anterior cardinal 
narrow, oblique and joined to median cardinal; median cardinal thick, moderately raised; posterior 
cardinal oblique, narrow; cardinal pit deep; inner margin ridged. Hinge of right valve with deep. 
anterior lateral tooth pit; anterior cardinal narrow, raised, separated from the lower edge of the hinge 
plate, joined to median tooth at dorsal side of hinge plate; median cardinal narrow, peg-like; 
posterior cardinal bifid, oblique. Adductor muscle scars and pallial line poorly defined. External 
colour white, with blue-white growth pauses, usually with an orange ray extending from the umbones 
to the postero-ventral margin and an orange escutcheon and lunule. White specimens also occut 
often with tan-coloured zig-zag patterns. Internally the valves are glossy white with blue-white 
growth pauses showing through the shell surface. 
Material examined: Holotype: MNHN - Nouvelle-Caledonie: Grand Recif Sud (Lagon: Іру, stn 361, 
229365, 167°02'E, 29 Nov 1984, 78m). Length (anterior to posterior margin) 20.7mm, height (umbo 
to ventral margin) 18.3mm, width of conjoined valves 14.5mm. | 
Paratypes: MNHN - Nouvelle-Caledonie: Grand Recif Sud (Lagon: AM C305574, 3pv, stn 361, 
229365, 167°02'E, 29 Nov 1984, 78m; Іру, 3lv, Irv, stn 370, 222385, 167°06'E, 30 Nov 1984, 
127m; Lagon: 2pv, 2гу, stn 397, 22?39'S, 167?11'E, 23 Jan 1985, 125m; Іру, llv, 1 rv, stn 429, 
225405, 167°15'E, 25 Jan 1985, 95m); Sud Nouvelle-Caledonie (Lagon SMIB: бру, 2rv, stn DW81, 
22°38'S, 167?35'E, 9 Sept 1989, 110m); Lagon Nord (Lagon: Ipv, stn 484, 19°00'5, 163°35'Е, Д 
Mar 1985, 35m; 5pv, stn 517, 192095, 163°35'E, 5 Mar 1985, 42m; Іру, stn 522, 19°08'S, 168°38'E, 
5 Маг 1985, 42m). 
Other material examined: Plateau Chesterfield-Bellona (Chalcal 1: stn D14, 2rv, Пу; stn 55, 11У; stn 
57, Пу). Nouvelle-Caledonie: Grand Recif Sud (Lagon: stn 320, 2pv, Irv, ПУ, 70 m; stn 367, 11v; 
stn 368, 1lv; stn 369, 11У; stn 370, Іру, 3lv, Irv, 127 m; stn 386, 1lv; stn 417, Irv; stn 429, Irv); 
Lagon Nord (Lagon: stn 484, Ipv, 35 m; stn 486, Іру, 33 m; stn 531, Ipv, Irv, 56 m); Secteur de 
Poindimie (Lagon: stn 772, Іру, llv, 30 m); Secteur des Belep (Lagon: stn 1064, Пу; stn 1099, 11v; 
stn 1103, 3pv, Пу, Irv, 32 m; stn 1117, 7pv, Пу, 36 m; stn 1129, 9ру, 11У, Irv, 40 m; stn 1168, 11v; 
stn 1205, Ipv, 38 m). 
Remarks: Compared with Lioconcha philippinarum (Hanley) and L. dautzenbergi (Prashad), L. 
melharteae sp. nov. has a far greater number of concentric, flattened ridges with narrow interstices 
(rounded, wider in L. philippinarum and separated by deep furrow-like interstices; much wider, 
rounder in L. dautzenbergi and with narrow, shallow interstices). In addition L. melharteae is always 
white externally while L. philippinarum and L. dautzenbergi are predominantly brown with some 
white zigzag patterns; internally these latter species are coloured whereas L. melharteae is glossy 
white. 
Lioconcha (Sulcilioconcha) richerdeforgesi sp. nov. 
(Figures 3d-f; 4a-b) 
Etymology: Named for Bertrand Richer de Forges who led the ORSTOM expeditions. 
Diagnosis: Shell to 11.25mm in length, 9.4mm in height and 6.7mm in width (paired valves); ovate: 
equivalve, slightly inequilateral. Umbones situated anteriorly; moderately inflated, fragile; 
prosogyrate. Lunule narrowly cordate, raised centrally, surrounded by an impressed line; escutcheon 
short, lanceolate, impressed. Antero-dorsal margin short, widely rounded to the antero-ventral 
margin; postero-dorsal margin moderately convex, slightly sloping, broadly rounded posteriorly; 
ventral margin widely rounded. Shell sculptured with dense, flattened concentric ribs which 
anastomose laterally; interstices narrow, shallow. Periostracum white, thick. Hinge of left valve with 
