Systematics and geographical distribution of Galba species, a group of cryptic and worldwide freshwater snails

Cryptic species can present a significant challenge to the application of systematic and biogeographic principles, especially if they are invasive or transmit parasites pathogens. Detecting cryptic requires pluralistic approach in which molecular markers facilitate detection coherent taxonomic units that then be analyzed using various traits (e.g., internal morphology) crosses. In asexual self-fertilizing species, latter criteria limited use. We studied group freshwater snails (genus Galba) from family Lymnaeidae have invaded almost all continents, reproducing mainly by self-fertilization transmitting liver flukes humans livestock. aim clarify systematics, distribution, phylogeny these with an integrative includes morphology, markers, wide-scale sampling across America, data retrieved GenBank (to include Old World samples). Our phylogenetic analysis suggests genus Galba originated ca. 22 Myr ago today comprises six complexes. Four them show elongated-shell phenotype exhibit wide variation their genetic diversity, geographic invasiveness. The remaining two more geographically restricted distributions globose-shell phenotype, most likely phylogenetically derived elongated one. emphasize no should identified without markers. also discuss several hypotheses explain origin Galba, such as convergence morphological stasis.