Subterranean aquatic planarians of Maryland and adjoining areas in West Virginia and Pennsylvania, U.S.A: new records and new species

The paper documents a collection of freshwater planarians from caves and springs in Maryland and adjoining regions in West Virginia and Pennsylvania. This resulted in new records for a number of already known species from the genera Paraplanaria, Phagocata, Procotyla, and Sphalloplana, as well as records for four new species, viz., Phagocata dissimilis Sluys, sp. nov., Phagocata projecta Sluys, sp. nov., Sphalloplana cava Sluys, sp. nov., and Sphalloplana obscura Sluys, sp. nov. It may be the case that some of the previous records of Phagocata gracilis actually concern Ph. projecta. Our analysis suggests that Procotyla typhlops is a junior synonym of Pr. fluviatilis. Particular attention is paid to the ecology and biogeography of the species, notably to the physiographic provinces from which the specimens were sampled.