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Diagram 1. Dendrogram of species of Pisaurina based on the structure 
of male pedipalpi. 
States (Maps 3, 4). An explanation for this type of distribution is 
that speciation could have occurred as a result of genetic isolation 
consequent with the Pleistocene shoreline changes which produced 
isolated islands in the region of the state of Florida. The southern 
species, then, emerged on these islands and spread northward later 
when the islands were once more connected with the mainland. A 
more detailed discussion of this type of distribution as it occurs in 
Dolomedes is found elsewhere (Carico, in press). The phylogenetic 
relationships are shown in a dendrogram (Diagram 1). Two spe- 
cies, P. mira and P. brevipes, are very similar in general morphology, 
eye pattern and genitalia, and are more closely related than any other 
pair. They have been confused frequently, but there are very good 
characters which separate them. The remaining two species are 
rather enigmatic in that their general morphologies and eye patterns 
are similar, while their genitalia, particularly the male palpi, are quite 
different from each other. The male palpi, perhaps the best indi- 
cators of interspecific relationships, are used as a basis for specula- 
tion on the phylogeny of the genus. 
Some arachnologists have wondered about the relationships be- 
