Two new species of (Caenogastropoda, Lithoglyphidae) from southwest Oregon, USA, and a range extension for .

We describe two new species of pebblesnails (Lithoglyphidae: ) from southwest Oregon based on morphologic and mitochondrial DNA (COI, cytB) evidence. , which had been traditionally identified as prior to the recent restriction of the latter to the lower Columbia River drainage, lives in lotic habitats in the Umpqua River basin. This species is readily distinguished from closely related and by shell and anatomical characters, and by its mtDNA sequences (divergence >3.6% for both genes). ranges among lotic habitats in the North Umpqua River basin, and in the upper Rogue River drainage north of Little Butte Creek. This species differs from other congeners by >9.1% for both genes and is distinguished from closely similar and geographically proximal by several anatomical characters. Additionally, new records are provided for from the upper Rogue River basin south of Little Butte Creek, which extend the geographic range of this species about 80 km northward from the Sacramento River headwater region. This continues a recent series of taxonomic papers on the poorly known and little studied pebblesnail fauna of the vast Pacific watershed from northern California to southern British Columbia.