Published online by Cambridge University Press: 20 January 2017
Field evidence from the Atacama Desert of northern Chile indicates that the stratigraphic position of the land snail Bostryx variabilis Herm has been incorrectly assigned to a marine series of the lower Pleistocene. Isotopic dating proves that the snail is a recently extinct Holocene taxon requiring no special paleoenvironmental explanations for its presence. However, the snail appears to offer an example of stress-induced speciation in confirmation of the “punctuated equilibrium” theory of evolution. It was probably transported from a fog oasis mountain habitat to a lower, hyperarid hostile environment by a sudden mudflow.