Geographic distribution of eastern Blepsimolge mtDNA clades in relation to species boundaries, habitat and major physiographic features. Squares and circles represent spring and cave localities, respectively. Clade associations are labeled by color for each sampled population; populations with haplotypes from two distinct clades are bicolored. Approximate distributions for Eurycea neotenes complex species (colored lines) are drawn according to designations by  although these designations are not entirely consistent with our phylogenetic hypotheses. Similarly, physiographic boundaries also appear to be poor predictors of mtDNA clade distributions. B9 = Bullis springs 9–83 and 9–29; CS = Comal Springs; PS = Pedernales Springs.