Shallow Waters, Deep Divergence: Epigean Amphipods Utilize Shallow Hyporheic Habitats in the Western Allegheny Plateau

Two new species of freshwater amphipods, Crangonyx ipnoecetes n. sp. and Crangonyx furnaricolus n. sp., are described from intermittent bodies of water in Vinton Furnace State Forest (VFSF), Vinton County, Ohio, USA. The descriptions of these species are based on both morphological and molecular analyses, which identify them as only distantly related despite their syntopic occurrences. These species are estimated to have last shared a common ancestor during the Late Cretaceous or early Paleogene (73–50 Ma) and to have diverged from their closest congeners towards the end of this period. Given the region occupied by these species, it is likely that their distributions were influenced by both preglacial habitats, such as the Teays River, and postglacial structures, such as Lake Tight. Our results suggest that significant gaps in knowledge still exist for the amphipod fauna of the Western Allegheny Plateau (eastern USA), with implications for taxonomy and conservation of Crangonyx as well as the natural history of the plateau and surrounding region. Furthermore, the description of these species provides additional evidence for the utilization of shallow hyporheic habitats by epigean Crangonyx spp. These habitats may play significant roles not only for these species, but for other epigean taxa as well.