New Data on Distribution of Two Alien Species of Land Snails of the Family Helicidae in European Russia

Abstract

New localities of C. nemoralis in Nizhny Novgorod oblast (the city of Nizhny Novgorod), which are to date the easternmost in Europe, and two new localities of A. arbustorum in the city of Dzerzhinsk (Nizhny Novgorod oblast) and the settlement of Borok (Yaroslavl oblast) are revealed. Morphological variability and modern trends in the spread of C. nemoralis are discussed. It is shown that the diversity of morphs in the sites of introduction is significantly lower than in the regions of the main range.