Species delimitation and taxonomy of the breve species group including analysis of genomic architecture of type specimen

The breve species group includes closely related Bembidion Latreille ground beetles commonly found at high elevation in the mountains of western North America. For several decades the group has been considered to consists of two species. Here we present evidence from morphological, molecular and geographic data that the group contains nine species: Bembidion. ampliatum, B. breve, B. geopearlis, B. laxatum, B. lividulum, B. oromaia, B. saturatum, B. testatum, and B. vulcanix. We describe three species (B. geopearlis, B. oromaia, and B. vulcanix) as new, and resurrect four previously synonymized names (B. ampliatum, B. lividulum, B. saturatum, and B. testatum). Species diversity is highest throughout the Sierra Nevada and Cascades in California, Oregon, and Washington, where up to seven species can occur in sympatry. We resolved challenging nomenclatural issues through analysis of sequences obtained from century-old type specimens by using a novel application of rDNA copy number analysis — an approach that may prove useful for other historical specimens.