Trends in Scorpion Diversity Along the Baja California Peninsula

Abstract

The scorpion fauna of Baja California, Mexico, was analyzed to identify the processes responsible for the observed patterns of diversity. We considered both the probability that equilibrial processes operate on the present population, by testing for a and the historical, ecological, and evolutionary characteristics of the scorpions. The most diverse scorpion fauna in the world occurs in Baja California, with at least 53 species on the peninsula and an additional 8 species on the associated islands. Fewer species are found at the northern base of the peninsula (5) than either at the southern tip (8) or in the lower mid-peninsular region (10-13). This pattern is opposite to the one expected from the peninsular effect, which predicts that an equilibrium between extinction and (re)colonization will lead to fewer species at the tip of the peninsula than at the base. In general, equilibrial processes contribute little to an understanding of the patterns of scorpion diversity; evidence sugge...