|Original name||Amussium watsoni Smith, 1885|
|Autoreference||Smith, 1885: 309, pl. 22, figs 8-8c.|
|Reference||Smith, E.A., 1885. Report on the Lamellibranchiata collected by H.M.S. "Challenger" during the years 1873-1876. - Challenger Reports, Zoology, 13 (35): 1-341.|
|Type data||Lectotype (pr: H 51.8 mm, L 50.0 mm, D 9.5 mm) The Natural History Museum, London (BMNH 18126.96.36.19907), designated by Dijkstra (1995: 24).Type locality: N of New Guinea, 02*23'S, 144*04'E, 1957 m, alive, blue mud, 01.iii.1875 ("Challenger" stn 218).|
Shell up to ca. 60 mm high, semi-transparent to opaque, weakly inflated, nearly circular, left valve slightly more convex than right valve, inequivalve, slightly equilateral, auricles nearly equal in size with delicate commarginal lamellae, colour of left valve whitish, right valve creamy.
Left valve with irregularly spaced, delicate radial lirae to the central part of the disc, closely spaced commarginal lamellae near the margin.
Right valve with regularly spaced commarginal lirae. Internal ribs 10 and an auricular riblet on each side. Byssal notch and ctenolium lacking.
Zanzibar area, Gulf of Aden, Arabian Sea, Laccadive Sea, Bay of Bengal, Strait of Malacca, Japan, N New Guinea (TL), Chesterfield Islands, New Caledonia, Loyalty Islands, Vanuatu Archipelago
|Habitat||Living bathyally on soft bottom assemblages.|