Biogeography and ecology of terrestrial isopods from Tuscany

The taxonomy, geographical distribution and ecology of the Oniscidea from Tuscany (central Italy) have been invesigated. This fauna includes 121 species, a very conspicuous number considering the area. Characteristic of this fauna are a group of species with a so-called Tyrrhenian distribution, constituted mainly of endogean species and/or species with a very limited distribution, and a second group of species with Alpine-Apennine distribution, most of which haave a wide range. Almost all the 24 species endemic to Tuscany belong to the Tyrrhenian group and are concentrated in the islands and on the hills nearest the coast. The Tyrrhenian forms are dominant in the islands and well represented on the non-Apennine reliefs but are almost absent in the remaining area. The Alpine-Apennine forms are dominant in the Apennines with a few forms having colonized much of Tuscany. If geographical and ecological factors serve to explain the present distribution of this fauna, historical factors are important to understand its origin.