Survey of Pogonognathellus Börner (Collembola: Tomoceridae) in the Southern Appalachians Based on Morphological and Molecular Data

Abstract

Abstract Pogonognathellus Börner is the most common genus of tomocerid Collembola in the southern Appalachian region of the United States. Scale pattern, cuticle color, and molecular data were used with morphology and chaetotaxy to reappraise the members of this genus. P. bidentatus and P. elongatus are confirmed as well-marked species; P. nigritus Maynard is removed from synonymy with P. elongatus and reestablished as a valid species, and a neotype is designated. Two new species are described. Pogonognathellus danieli n. sp. from a cave in Great Smoky Mountains National Park resembles the California cave species P. celsus but possesses clubbed tenent hairs on all tibiotarsi; in P. celsus, the tenent hairs are pointed. P. mystax n. sp. is related to the “P. flavescens complex” but differs in having a purple clypeus and a prominent band of light scales along the posterior edge of each tergite. Many collections of P. flavescens-like and P. dubius-like specimens were made but molecular analysis indicated that these specimens consisted of four P. dubius-like taxa and four P. flavescens-like taxa. True P. flavescens from Sweden (type locality) were molecularly distinct from the putative American P. flavescens included in the analysis. A tentative phylogenetic tree indicated three clades of southern Appalachian Pogonognathellus: one clade containing P. bidentatus; another clade containing species with posterior cephalic macrochaetae but without anterior macrochaetae on the fourth abdominal tergite (Abd. IV; P. elongatus, P. nigritus, and an undescribed species); and a third clade without posterior cephalic macrochaetae but with one pair of anterior macrochaetae on Abd. IV (P. danieli, P. mystax, and eight undescribed species).