PHYLOGENETIC IMPLICATIONS OF CHROMOSOME EVOLUTION IN GEOMYS

A phylogenetic analysis of the variation seen in 85 characters involving the G-, R-, DAPI/ AMD, and C-band patterns produced a cladogram that is congruent with cladograms previously reported for Geomys and based on biochemical, karyotypic, or restriction site-based data. Three clades are recognized: G. breviceps; G. attwateri-G. personatus; G. texensis-G. bursarius. Few structural rearrangements separate these clades indicating that chromosomal evolution is more conservative than previously hypothesized. However, constitutive heterochromatin and fluorescent staining patterns reveal cryptic variation to be common among these taxa.