Arthropod diversity in shallow subterranean habitats of the Appalachian Mountains, morphospecies images, Part I

Subterranean arthropods are important components of soils and contribute essential food-web functions and other ecosystem services, however, their diversity and community composition has scarcely been assessed. Subterranean pitfall traps are a commonly used method for sampling soil habitats in Europe but have never been widely implemented in the Americas. We used subterranean pitfall traps to sample previously unsurveyed arthropod communities in southwestern Virginia, U.S. Traps were placed in shallow subterranean habitats (SSHs), underground habitats close to the surface where light does not penetrate, and more specifically at the interface between the soil and underlying milieu souterrain superficiel—a microhabitat consisting of the air-filled interstitial spaces between rocks (abbreviated MSS). In total, 2,260 arthropod specimens were collected constituting 345 morphospecies from 8 classes, 33 orders, and 94 families. A region of the mitochondrial cytochrome c oxidase subunit I (COI) gene was amplified and sequenced, and objective sequence clustering of 3% was used to establish molecular operational taxonomic units (mOTUs) to infer observed species richness. In all, 272 COI barcodes representing 256 mOTUs were documented for rare soil-dwelling arthropod taxa and are published to build a molecular library for future research in this system. This work is the first taxonomically extensive survey of North American soil-dwelling arthropods greater than 10 cm below the soil surface.