Prima segnalazione del gambero alloctono Pacifastacus leniusculus (Decapoda, Astacidae) in Provincia di Savona, Italia

First reporting of the signal crayfish (Decapoda, Astaci- dae) in the Province of Savona, Italy. In this short note we report the sudden and numerically significant expansion of signal crayfish (P. leniusculus) from Piedmont towards Liguria. P. leniusculus (Decapode Astacidae) is native to northwest- ern America, introduced in Italy in 1981 in the province of Bolzano, a few years later it was reported in Brugneto Lake (Genova district) and during the 2009 in the Valla stream (Alessandria district). The peculiari- ties of this species, originally from "cold water", making it potentially invasive in the Apennine watercourses and also the presence of this allochthonous decapod in the Savona district, would like to suggest the implementation of containment plans, acts at least to limit its spread.