Amalda

The thin shell is not umbilicated. The spire is elongated with the suture enamelled. The primary spire callus covers most of the spire, including at least part of the protoconch, leaving in most cases only the first protoconch whorl exposed.^[3] The inner lip has the callus moderate, defined. The outer lip is simple.^[4]

These snails usually live in the sand in fairly shallow water in tropical and temperate regions of the world with a particularly rich fauna in Australia and the Indo-West Pacific. Most species are predators of marine bivalves.^[5][6][7]

In general, both shallow and deep-water species of Amalda tend to have relatively narrow distribution ranges within the Indo-Pacific, where local faunas are often dominated by narrow endemics, particularly in South Africa and, to a lesser extent, Australia. While some species exhibit broader distributions—such as A. hinomotoensis, found from Japan to Taiwan, and A. mamillata, present in regions including Indonesia, the Strait of Malacca, Vietnam, and the China Seas (Gratecap 2016b)—such broad distributions should be interpreted with caution.^[3][8]

Species within the genus Amalda include:^[9][10]

• Amalda albicallosa [sic]: synonym of Amalda albocallosa (Lischke, 1873)
• Amalda ampla (Gmelin, 1791): synonym of Ancilla ampla (Gmelin, 1791)
• † Amalda buccinoides (Lamarck, 1803): synonym of † Spirancilla buccinoides (Lamarck, 1803)
• Amalda callifera Thiele, 1925: synonym of Amalda reevei (E.A. Smith, 1904)
• Amalda dyspetes (Iredale, 1924): synonym of Amalda marginata (Lamarck, 1811)
• Amalda elongata (Gray, 1874): synonym of Ancillista muscae (Pilsbry, 1926)
• Amalda errorum Tomlin, 1921: synonym of Amalda angustata (G.B. Sowerby II, 1859)
• Amalda fusiformis (Petterdi, 1886): synonym of Amalda petterdi (Tate, 1893) (invalid: not J. Sowerby, 1850)
• Amalda hayashi Ninomiya, 1988: synonym of Amalda rubiginosa (Swainson, 1823)
• Amalda lanceolata Ninomiya, 1991: synonym of Amalda petterdi (Tate, 1893) (junior subjective synonym)
• † Amalda lanceolata (Tate, 1889): synonym of † Baryspira lanceolata (Tate, 1889) (superseded combination)
• Amalda maritzae Bozzetti, 2007: synonym of Amalda allaryi Bozzetti, 2007 (uncertain synonym)
• Amalda procerum Ninomiya, 1991: synonym of Amalda procera Ninomiya, 1991
• Amalda siberutensis Thiele, 1925: synonym of Ancilla siberutensis Thiele, 1925
• Amalda sibuetae Kantor & Bouchet, 1999: synonym of Turrancilla sibuetae (Kantor & Bouchet, 1999) (original combination)
• Amalda sidneyensis Ninomiya, 1991: synonym of Amalda edithae (Pritchard & Gatliff, 1899) (junior subjective synonym)
• Amalda tankervillei (Swainson, 1825): synonym of Amalda tankervillii (Swainson, 1825)
• Amalda virgineus Ninomiya, 1990: synonym of Amalda virginea Ninomiya, 1990
• Amalda zeigleri Ninomiya, 1987: synonym of Amalda pacei Petuch, 1987