PORCELLIONIDES FLORIA, NEW SPECIES, FROM NORTH AMERICA; PROVINCIALITY IN THE COSMOPOLITAN ISOPOD PORCELLIONIDES PRUINOSUS (BRANDT)

ABSTRACT Porcellionidespruinosus (Brandt) is widely distributed throughout the world but shows extensive, albeit subtle, geographical variation in morphology. This morphological variation has resulted in a complex and confused taxonomic history for the genus, with many new species having been described only to be subsequently synonymized with P. pruinosus. What has previously been considered to be P. pruinosus in North America is shown here to be two separate species. Although these species differ only subtly in morphology, they are electrophoretically, reproductively, and distributionally distinct. For one of these species, P. pruinosus(Brandt), electrophoretic, morphological, and reproductive comparisons of North American individuals with European samples suggest a European origin. The other species is not referable to any other described species of Porcellionides and is described as a new species. The results of this study suggest that Porcellionides pruinosus (as formerly defined) may consist of a number of distinct and localized species rather than one cosmopolitan species. Therefore, it would appear that the taxonomic status of Porcellionides pruinosus is in need of re-evaluation on a world-wide basis.