A systematic and biogeographical study of epi- and hypogean populations ofthe Proasellus species group from Sardinia, central Italy and Jordan: allozyme insights

Genetic variation at 18 enzymatic loci was investigated in 10 epigean and t hree hypogean populations belonging to the Proasellus (Asellidae, Crustacea ) species group, from Sardinia, central Italy, and Jordan, in order to clar ify their systematics and evolutionary relationships. We found unexpectedly high levels of genetic divergence, which allowed us to recognize a number of genetically distinct species presently hidden under the name Proasellus coxalis. The group of Sardinian populations is the most genetically differe ntiated. Among the central Italian populations, the northernmost population is the earliest branch in the proposed phyletic scheme, whereas the remain ing populations are genetically homogeneous and clustered as the sister tax on of the Sardinian populations. The Jordanian population is genetically di fferentiated versus both the central Italian and Sardinian groups. The evol utionary relationships seem to indicate that several waves of colonization by this genus occurred in Europe. The evolutionary times inferred from gene tic distance data place the main splitting events at the end of the Miocene , in agreement with the paleogeography of the study areas.