A molecular phylogeny of Mobile River drainage basin pleurocerid snails (Caenogastropoda: Cerithioidea).

Sequences from the mitochondrial 16S rRNA gene were obtained to construct a molecular phylogeny for Mobile River drainage basin pleurocerid snails. Data from 876 aligned positions generated a single most-parsimonious tree for each of three analytical approaches: (1) equal weighting, (2) transversions weighted 2 x transitions; and (3) transversions weighted 4 x transitions. Identical topologies for the resulting trees depict the genera Elimia and Pleurocera as monophyletic sister taxa. The genus Leptoxis is paraphyletic with Leptoxis plicata sister to the Elimia + Pleurocera clade. L. taeniata and L. ampla are sister taxa and L. picta is the most basal pleurocerid examined. When transversions were weighted 10x transitions a single most-parsimonious tree was obtained with the only topological difference being L. picta depicted as sister to L. taeniata and L. ampla and L. plicata is now the most basal pleurocerid examined. Many of the Elimia species are closely related, but we await further data before making any taxonomic recommendations. L. picta and L. plicata are quite distinct from each other and all other pleurocerid species examined. These data serves as an important foundation for future studies examining conservation genetics and systematics of this diverse and imperiled family.