The biology, ecology, biogeography, phylogeny, and evolution of sand-d
welling scorpions are reviewed. We present general features of sand th
at form the ecological theatre on which psammophiles have evolved. San
d scorpions, compared to those that live off sand, are not very divers
e in any one local habitat, although they are often relatively abundan
t. Worldwide, they are represented by 29 genera, 11 of which exist exc
lusively in sand. Endemic genera belong to non-related families, sugge
sting that psammophilic adaptations evolved in situ in different sand
deserts of the world. (C) 1998 Academic Press.