Diagnosis
Shell thin but strong, ovate-trigonal, smooth but not glossy, lunule heart-shaped, outlined by deeply incised line. Sculpture of dense (approximately 80) raised, concentric, rounded ridges developed as fine ribs, which become wrinkled at the anterior and posterior extremities. Colour externally translucent white, with orange ray extending from umbones to posteroventral margin; dorsal margin and lunule also orange; umbones white; internally glossy white with blue-white growth pauses showing through shell surface. Shell length to 21 mm.

Distribution and habitat
Known only from New Caledonia, in sand to 127 m. Material examined Holotype. New Caledonia: Grand Recif Sud (Lagon: (lpv) stn 361, 22°36'S, 167°02'E, 29 Nov 1984, 78 m, MNHN.
Paratypes. New Caledonia: Grand Recif Sud (lpv, 31v, lrv) stn 370,22°38'S, 167°06'E, 30 Nov 1984, 127 m; Lagon: (2pv, 2rv) stn 397,22°39'S, 167°1 l'E, 23 Jan 1985, 125 m;(lpv, llv, lrv)stn429, 22°40'S, 167°15'E, 25 Jan 1985, 95 m); Sud Nouvelle-Caledonie (Lagon SMIB: (6pv, 2rv) stn DW81, 22°38'S, 167°35'E, 9 Sep 1989, 110 m); Lagon Nord (Lagon: (lpv) stn 484, 19°00'S, 163°35'E, 2 Mar 1985, 35 m; (5pv)stn517, 19°09'S, 163°35'E, 5 Mar 1985,42 m; (lpv) stn 522, 19°08'S, 168°38'E, 5 Mar 1985,42 m, MNHN; (Lagon: Stn 361, 22°36'S, 167°02'E, 29 Nov 1984, 78 m, AM C.305574 (3pv).
Other material examined. Other New Caledonian (ORSTOM) material is listed by Lamprell and Stanisic (1996), but note that some of these specimens now form the type scries for L. caledonesis Hartc & Lamprell, 1999.

The thin, strongly inflated, closely ridged valves, featuring a single orange ray posteriorly and an orange dorsal margin and lunule make this a very distinctive species. Lioconcha melharteae, as now redefined, is unlikely to be confused with any other species of Lioconcha. In their original description, Lamprell and Stanisic (1996) included, together with typical L. melharteae, less inflated specimens that lacked the orange colouration of ray, dorsal margin and lunule. Subsequently, Harte and Lamprell (1999) described these specimens as L. caledonensis. Although L. caledonensis shows a similar ridged sculpture to L. melharteae, it differs in having less inflated valves (narrowed posteriorly) and a pattern of widely scattered brown flecks on its white shell. The two species occur sympatrically off New Caledonia, but have yet to be collected outside this region. Sculptural and, especially, colour pattern and valve profile differences easily separate L. melharteae from other species within the heavily ridged Lioconcha group, such as L. philippinarum, L. richerdeforgesi and L. trimaculata.