Fw. Welter-schultes, Spatial variations in Albinaria terebra land snail morphology in Crete (Pulmonata : Clausiliidae): constraints for older and younger colonizations?, PALEOBIOL, 27(2), 2001, pp. 348-368
A spatial approach was employed to test whether the conchological different
iation of the Recent land snail Albinaria terebra from southern central Cre
te (Greece) is decreased in areas that have been more recently colonized by
the species. The eastern Mediterranean genus Albinaria has produced more t
han 120 species, probably in pre-Tortonian events of radiation. A. terebra
occupies a compact range of 550 km(2) consisting partly of late Cenozoic de
posits of different ages, partly of pre-Cenozoic formations. The morphologi
cal study was based on 300 samples distributed over the entire range of the
species. Shell size, shape, whorls, and teleoconch rib densities exhibited
no evident correlation with environment but were subjected to considerable
spatial variations. The differentiation, determined as the difference of t
he mentioned shell parameters between one population and another population
2-4 km distant, was found to increase continuously with the time (1-12 Myr
) the land has been exposed to air. The populations with the highest degree
s of spatial variation came from two areas that have never been submerged i
n the late Cenozoic, possibly the oldest populations of the species. It is
plausible that the other areas were colonized by range expansion after late
Neogene periods of tectonic uplift. The results are consistent with previo
us conclusions derived from molecular studies setting the radiation of Albi
naria prior to the Tortonian and imply that we might be in possession of a
new tool to detect information on the phylogeographic history of land snail
species.