New data on biogeography, classification and phylogeny of Рhysidae (Gastropoda: Hygrophila)

Physidae are a family of freshwater pulmonate gastropods with about 90-100 named species, newly divided among 23 genera in seven tribes and four clades. Morphological studies resulted in discovery of many new characters, some of them progressive, yielding criteria for primitive versus advanced states. Thus it is possible to assert that primitive groups are concentrated on the Pacific coast from Mexico to Costa Rica, and to trace the spread of lineages from this region to other parts of the world.