Xerosecta giustii a new hygromiid from Tuscany (Italy) close to extinction (Gastropoda, Pulmonata: Helicoidea)

Xerosecta giustii n. sp. is described from one locality in the Colline Metallifere (southern Tuscany, Italy). The new species is easily distinguished from all the other species of Xerosecta, both conchologically by virtue of its medium-sized, subglobose to depressed, robust shell, usually opaque, waxen, uniformly grey to whitish-grey in colour, and anatomically by genitalia as in Xerosecta species, but with a voluminous genital atrium containing a large, crest-like structure. The new species has only been found in the type locality and, at present, no other species endemic to Tuscany is known to have such a reduced distribution. This population did not seem to be threatened by human activity. Live snails, however, can no longer be found. A long drought in the winter of 1992–93 and the spring of 1993 and ploughing of part of the site might be responsible for disappearance of the population.