Invertebrates specialized for life in groundwater (stygobionts) are diverse and widely distributed in Europe but poorly known in North America. A survey of the invertebrate fauna at 14 sites in eastern North America shows that unglaciated ancient terrain in eastern North America contains a rich fauna of stygobionts. Several groups of stygobionts (the polychaete Troglochaetus sp., an undescribed genus of aphanoneuran annelid, a possibly undescribed family of oligochaetes, bathynellacean crustaceans, and microcerberid isopods) are reported for the first time from eastern North America. Stygobionts are infrequent north of the glacial border, suggesting that they have not yet been able to disperse into glaciated terrain. The extraordinarily slow dispersal rates implied by these distributions have important ecological ramifications. The few stygobionts found north of the glacial border may have survived glaciation in subglacial refugia.
