Diversity of North American Pogonognathellus (Collembola: Tomoceridae)

Tomoceridae are large, heavily scaled, common springtails found throughout the U.S. Pogonognathellus is the most widespread and diverse genus, with 5 currently recognized species. Several of these species are difficult to identify as their morphology is similar, chaetotaxy is strongly reduced, and scales are easily dislodged during collection and in preservative. The use of pristine scale patterns on live specimens, ground color, head markings, and molecular analysis to separate taxa indicates that species diversity of this genus is much greater in the U.S. than previously known. The southern Appalachian region alone probably has at least 12 species, several of which are currently lumped in P. dubius or P. flavescens; other new taxa have been collected from other regions, including Alaska. The name P. flavescens probably should be reserved for Palearctic forms, as putative American P. flavescens are molecularly distant from true P. flavescens collected near the type locality (Sweden).