skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.


Title: Trechus (Coleoptera: Carabidae) of Appalachia: A Phylogenetic Insight into the History of High Elevation Leaf Litter Communities
Elevation gradients provide a wealth of habitats for a wide variety of organisms. The southern Appalachian Mountains in eastern United States are known for their high biodiversity and rates of endemism in arthropods, including in high-elevation leaf-litter taxa that are often found nowhere else on earth. Trechus Clairville (Coleoptera: Carabidae) is a genus of litter inhabitants with a near-global distribution and over 50 Appalachian species. These span two subgenera, Trechus s. str. and Microtrechus Jeannel, largely restricted to north and south of the Asheville basin, respectively. Understanding the diversification of these 3–5 mm flightless beetles through geological time can provide insights into how the litter-arthropod community has responded to historical environments, and how they may react to current and future climate change. We identified beetles morphologically and sequenced six genes to reconstruct a phylogeny of the Appalachian Trechus. We confirmed the Asheville Basin as a biogeographical barrier with a split between the north and south occurring towards the end of the Pliocene. Finer scale biogeography, including mountain-range occupancy, was not a reliable indication of relatedness, with group ranges overlapping and many instances of species-, species group-, and subgeneric sympatry. This may be because of the recent divergence between modern species and species groups. Extensive taxonomic revision of the group is required for Trechus to be useful as a bioindicator, but their high population density and speciose nature make them worth additional time and resources.  more » « less
Award ID(s):
1916263
PAR ID:
10505276
Author(s) / Creator(s):
;
Publisher / Repository:
Diversity
Date Published:
Journal Name:
Diversity
Volume:
16
Issue:
4(212)
ISSN:
1424-2818
Page Range / eLocation ID:
1-15
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Abstract Developing systematic conservation plans depends on a wealth of information on a region's biodiversity. For ‘dark taxa' such as arthropods, such data are usually very incomplete and in most cases left out from assessments.Sky islands are important and often fragile biodiversity hotspots. Southern Appalachian high‐elevation spruce–fir forests represent a particularly threatened sky‐island ecosystem, hosting numerous endemic and threatened species, but their arthropods remain understudied.Here we use voucher‐based megabarcoding to explore genetic differentiation among leaf‐litter arthropod communities of these highlands, and to examine the extent to which they represent dispersed communities of more or less coherent species, manageable as a distributed unit. We assembled a dataset comprising more than 6000 COI sequences representing diverse arthropod groups to assess species richness and sharing across peaks and ranges. Comparisons were standardised across taxa using automated species delimitation, measuring endemism levels by putative species.Species richness was high, with sites hosting from 86 to 199 litter arthropod species (not including mites or myriapods). Community profiles suggest that around one fourth of these species are unique to single sky islands and more than one third of all species are limited to a particular range. Across major taxa, endemicity was lowest in Araneae, and highest in neglected groups like Isopoda, Pseudoscorpionida, Protura and Diplura.Southern Appalachian sky islands of spruce–fir habitat host significantly distinct leaf‐litter arthropod communities, with high levels of local endemicity. This is the first work to provide such a clear picture of peak and range uniqueness for a taxonomically broad sample. Ensuring the protection of a sizeable fraction of high‐elevation litter species richness will therefore require attention at a relatively fine spatial scale. 
    more » « less
  2. The small, eyeless beetles of the genus Anillinus Casey (Coleoptera: Carabidae: Trechinae: Anillini) comprise a diverse, ubiquitous, but poorly known component of insect biodiversity in the southeastern United States. Their limited dispersal capabilities make them ideal subjects for biogeography, but taxonomic problems and undescribed species diversity hamper such studies. In this paper, we redescribe four enigmatic species, Anillinus docwatsoni Sokolov and Carlton, Anillinus elongatus Jeannel, Anillinus pecki Giachino, and Anillinus turneri Jeannel, and consider their relationships. The elongatus species group is revised, with descriptions of four newly discovered species, Anillinus arenicollis Harden and Caterino, new species, Anillinus montrex Harden and Caterino, new species, Anillinus pittsylvanicus Harden and Caterino, new species, and Anillinus uwharrie Harden and Caterino, new species. Two species previously considered part of the elongatus group are determined to not belong here, Anillinus cavicola Sokolov and Anillinus turneri Jeannel. The exact placement of A. turneri remains uncertain, but it shares some character states with the sinuaticollis group. We erect the pecki group for A. docwatsoni and A. pecki, which are likely sister species. We provide a key to the eastern species groups of Anillinus and the species of the elongatus and pecki species groups. Anillinus pecki is broadly distributed in the southern Appalachian Mountains northeast of the French Broad River basin, while A. docwatsoni is apparently endemic to the Hickory Nut Gorge in western North Carolina. Anillinus pecki is reported for the first time from Tennessee and Virginia. All members of the elongatus group have small geographic ranges and are difficult to sample without special techniques, hinting that many more species await discovery in the densely populated Piedmont region of North Carolina, where natural habitats are rapidly being lost. Our sampling was not dense enough to test biogeographic hypotheses, but distributions of the elongatus group species suggest that hydrochory might have played an important role in passive dispersal and reproductive isolation. These taxonomic contributions will facilitate future studies on the genus and serve to highlight the rich insect biodiversity that remains to be discovered in the southeastern United States. 
    more » « less
  3. Although many new species of the millipede genus Nannaria Chamberlin, 1918 have been known from museum collections for over half a century, a systematic revision has not been undertaken until recently. There are two species groups in the genus: the minor species group and the wilsoni species group. In this study, the wilsoni species group was investigated. Specimens were collected from throughout its distribution in the Appalachian Mountains of the eastern United States and used for a multi-gene molecular phylogeny. The phylogenetic tree recovered Nannaria and the two species groups as monophyletic, with Oenomaea pulchella as its sister group. Seventeen new species were described, bringing the composition of the wilsoni species group to 24 species, more than tripling its known diversity, and increasing the total number of described Nannaria species to 78. The genus now has the greatest number of species in the family Xystodesmidae. Museum holdings of Nannaria were catalogued, and a total of 1,835 records used to produce a distribution map of the species group. Live photographs, illustrations of diagnostic characters, ecological notes, and conservation statuses are given. The wilsoni species group is restricted to the Appalachian region, unlike the widely-distributed minor species group (known throughout eastern North America), and has a distinct gap in its distribution in northeastern Tennessee and adjacent northwestern North Carolina. The wilsoni species group seems to be adapted to mesic microhabitats in middle to high elevation forests in eastern North America. New species are expected to be discovered in the southern Appalachian Mountains. 
    more » « less
  4. The Pseudoscorpiones fauna of North America is diverse, but in regions like the southern Appalachian Mountains, they are still poorly documented with respect to their species diversity, distributions and ecology. Several families have been reported from these mountains and neighbouring areas. Here we analyse barcoding data of 136 specimens collected in leaf litter, most of them from high-elevation coniferous forest. We used ASAP as a species delimitation method to obtain an estimation of the number of species present in the region. For this and based on interspecific genetic distance values previously reported in Pseudoscorpions, we considered three different genetic Kimura two-parameter distance thresholds (3%/5%/8%), to produce more or less conservative estimates. These distance thresholds resulted in 64/47/27 distinct potential species representing the families Chthoniidae (33/22/12 species) and Neobisiidae (31/25/15) and at least six different genera within them. The diversity pattern seems to be affected by the Asheville Depression, a major biogeographic barrier in this area, with a higher diversity to the west of this geographic feature, particularly within the family Neobisiidae. The absence of representatives from other families amongst our studied samples may be explained by differences in their ecological requirements and occupation of different microhabitats. 
    more » « less
  5. Arthonia ligniariella is reported for the first time from eastern North America based on a collection growing on lignum in North Carolina, U.S.A. Biatora appalachensis, an Appalachian endemic, is shown to be widespread throughout the Appalachian Mountains, primarily at high elevations. The only report of Fellhanera parvula from North America (Tennessee, U.S.A.) is considered to be F. bouteillei. Fellhanera subtilis, previously reported in North America from the Pacific Northwest, is reported for the first time from eastern North America (southern Appalachian Mountains). Gyalideopsis mexicana, previously reported in North America from the Yukon, Canada and New Mexico, U.S.A. is newly reported from eastern North America (southern Appalachian Mountains, North Carolina, U.S.A.). Lepra ouahensis, a sorediate species with lichexanthone and stictic acid, is reported from disjunct areas of the southern Appalachian Mountains and the Southeastern Coastal Plain. Its distribution is compared to the lichexanthone producing chemotypes of L. trachythallina and Varicellaria velata. Rockefellera crossophylla, a rare species considered extinct in Pennsylvania, U.S.A. is reported to be extant in that state. Psoronactis dilleniana is newly reported from North America from high elevations of the central and southern Appalachian Mountains (North Carolina and Virginia U.S.A.). Xenonectriella streimannii is newly reported for North America based on a collection found growing on Anaptychia palmulata in Georgia, U.S.A. 
    more » « less