Snail - Amphidromus sp. | ©Paul Bertner (Mulu National Park, Borneo)
Amphidromus is a genus or arboreal pulmonate land snails belonging to the sigmurethran family Camaenidae (order Stylommatophora).
The shells of Amphidromus are relatively large, from 1-3 inches high, and colorful. One interesting fact of this genus is that has mixed dextral-sinistral populations (in reference to the direction -right or left- of rotation of the shell around its axis.
Sinistral mutants of normally dextral species and dextral mutants of normally sinistral species are rare but well documented occurrences among land snail. Populations or species with normally mixed coiling are much rarer, and confined to to a few genera of arboreal tropical snails. The independent appearance of this variation in unrelated groups is probably the result of a simple mutation [1].
Distribution of the genus Amphidromus include from eastern India in south-western Asia to northern Australia [2].
(via typhlonectes)