Sinistral Applesnails (Ampullariidae)

By Harry G. Lee

    The Applesnail guru, E. G. Alderson (1925), noted the reversal of the Applesnail images in the 18th century works of Seba and Rumphius and wrote: "We may remark that the sinistral shell thus artificially produced by these ancient authors is perhaps rarer in this genus than in any other." That perception notwithstanding, eleven species of ampulariids, from four continents, have been reported in the reverse-coiled condition:

Pila ampullacea (Linnaeus, 1758)  [Asia] Nevill, 1877; Dharma, 2005: pl. 15; also shown here (several others noted in the marketplace recently).
Pila carinata (Swainson, 1821) [Asia] Nevill, 1886.
Pila conica (Wood, 1818) [Asia] Letson, 1897.
Pila globosa (Swainson, 1821) [Asia]; shown here and here (several others noted in the marketplace recently).
Pila pesmei (Morelet, 1889) [Asia] Cazzaniga and Estebenet, 1990
Pila polita (Deshayes, 1830)  [Asia] Nevill, 1877; East Jawa (Dharma, 2005: pl. 15);
Pila scutulata (Mousson, 1848) [Asia] East Jawa (Dharma, 2005: pl. 15).
Pila wernei (Philippi, 1851) [Africa] Darteville, 1953 (as Pila wernei dewulfi Bequaert and Clench, 1933)
Pomacea canaliculata (Lamarck, 1822) [South America] Cazzaniga and Estebenet, 1990; widely introduced elsewhere including Jawa (Dharma, 2005:
pl. 15) and Vietnam, as shown here.
Pomacea paludosa (Say, 1829) [North America] Emery, 1943; V. Vail, pers. comm., 1978.
Pomacea urceus (Müller, 1774) [South America] Burky, 1974

    I know of no reported observation of the soft parts of an abnormally-reversed coiled ampulariid except for Cazzaniga and Estebenet (1990), who indicated that the animal of their Pomacea canaliculata was sinistral and that its operculum was a mirror image of a normal one.

Alderson, E.G., 1925. Studies in Ampullaria. W. Heffer and Sons, Cambridge. xx + 1-102 + 19 pls.
Burky, A.J., 1974. Growth and biomass production of an amphibious snail, Pomacea urceus (Müller), from the Venezuela savanna. Proceedings of the Malacological Society of London 41:     127-143.
Cazzaniga, N.J. and A.L. Estebenet, 1990. A sinistral Pomacea canaliculata (Gastropoda: Ampullariidae). Malacological Review 23: 99-102.
Darteville, E., 1953. A sinistral Pila from Africa. Journal of Conchology 23(9): 288-289, pl. 8.  
Dharma, B., 2005. Recent and fossil Indonesian Shells. Conchbooks, Hackenheim, Germany. pp. 1-424, incl. 150 pls.
Emery, D.L., 1943. Sinistral Pomacea. The Nautilus 57(2): 66.
Letson, J.E., 1897. Sinistral Ampullaria. The Nautilus 11(3): 33-34.
Nevill, G. 1877. Catalogue of the Mollusca in the Indian Museum, Calcutta Fasciculus E. Indian Museum, Calcutta. [iv] + 1-42.
Nevill, G., 1886. Hand List of Mollusca in the Indian Museum, Calcutta, pt. 2. Indian Museum, Calcutta. ix + 1-306.