A new species of stygobitic Hyalella Smith, 1874 (Amphipoda: Hyalellidae) from Ash Meadows National Wildlife Refuge, Nevada, USA, with discussion of the unique presence of the species in the Nearctic groundwater fauna

A new species of stygobitic hyalellid amphipod, Hyalella cretaen. sp., is described from Ash Meadows National Wildlife Refuge, Nye County, Nevada, USA, based on both morphological and molecular comparisons to congeners. These data identify H. cretaen. sp. as distinct when compared to allied species. Along with the similar Hyalella muertaBaldinger, Shepard & Threloff, 2000, H. cretaen. sp. marks the second described stygobitic species of Hyalella from the Nearctic. The occurrence of the genus in groundwater in the Nearctic is enigmatic, especially when compared to other more wide-ranging stygobites (e.g., Stygobromus spp., Hadziidae spp.). The biogeographic implications of the occurrence of species like H. muerta and H. cretaen. sp. in relation to other Nearctic stygobites is discussed.