Cavefish species diversity
Subterranean faunas and habitats remain poorly studied and explored compared to their surface counterparts. Many caves and regions have not been adequately bioinventoried. In addition, the majority of subterranean taxa have yet to be examined using molecular approaches. Consequently, there are still many exciting discoveries to be made. My molecular work on amblyopsid cavefishes strongly suggests that their are several evolutionary significant lineages in Typhlichthys and Amblyopsis that may represent new cryptic species. I am collaborating with ichthyologists Thomas J. Near (Yale University), Jon W. Armbruster (Auburn University), and Prosanta Chakrabarty (Louisiana State University) to examine morphological variation among these putative lineages in an effort to better understand taxonomic diversity in these enigmatic cavefishes. Preliminary analyses have uncovered subtle but diagnostic morphological variation among some lineages. One of our goals is to describe these lineages in the near future.
Primary Collaborators: Thomas J. Near (Yale University), Jon W. Armbruster (Auburn University), Prosanta Chakrabarty (Louisiana State University), Dante Fenolio (San Antonio Zoo), G.O. Graening (California State University)
Subterranean biodiversity in the Appalachian Valley and Ridge of Tennessee, Alabama and Georgia
Kirk Zigler and I recently compiled an updated faunal list of obligate
subterranean species in Tennessee to examine spatial patterns of species
richness and endemism (Niemiller & Zigler 2013). We identified a hotspot of biodiversity defined
by both species richness and endemism that runs along the escarpment of the
Cumberland Plateau in south-central Tennessee and that is contiguous with a
previously defined hotspot in northeastern Alabama. Diversity
in the Valley and Ridge of east Tennessee, however, was significantly lower than that of the Cumberland
Plateau and the Interior Plateau.
Several undersampled areas are noted, with one concentrated in northeast Tennessee extending
from the more intensely inventoried karst of southwestern Virginia. Only 5.0% of the known Appalachian Valley and Ridge caves have troglobiont records,
suggesting much diversity has yet to be discovered.
We are addressing sampling gaps in Appalachian Valley and Ridge caves by (1) conducting biological inventories and (2) documenting species occurrences that can define geographic extents. From this effort, we will begin to identify existing or future stressors that threaten species and populations in some well-known, but also little-studied, cave systems. Lastly, we propose to (3) develop an educational outreach program that will promote awareness and conservation of subterranean fauna, not just in the Tennessee Valley and Ridge but throughout the Appalachian Valley and Ridge.
As a preliminary examination of sampling gaps , we and a small group of other biospeleologists conducted bioinventories of four caves in Knox and Roane counties (in the middle of the Valley and Ridge in east Tennessee) and four caves in Hamilton County (at the southern edge of the Valley and Ridge in Tennessee) during the summer of 2013. Six of these caves had not been previously visited by biospeleologists. Although taxonomic identifications are ongoing, at least 15 cave species were documented from the eight caves. These records include new distributional records for wider-ranging species, such as the cave amphipod Crangonyx antennatus, and cave spider Porrhoma cavernicola, as well as narrowly-distributed species, such as the cave beetle Pseudanophthalmus tennesseensis, and the cave millipede Scoterpes blountensis. We also discovered several undescribed species, highlighted by the 1st records of hydrobiid cave snails in Tennessee (Fontigens n. sp.). Relatives of this new species are found to the north within the Valley and Ridge of the Virginias. We also collected the first Pseudanophthalmus beetles from the southern Tennessee Valley and Ridge, as well as likely a new cave millipede species (Pseudotremia n. sp.). Combined, the results of Niemiller and Zigler (2013) and documentation of new species distributions and discoveries from our preliminary biological inventories strongly demonstrate the need for additional inventories within the Appalachian Valley and Ridge of Tennessee, Alabama and Georgia. This recent work also confirms that future effort will yield new, successful results.
Primary Collaborators: Kirk S. Zigler (University of the South), Annette Summers-Engel (University of Tennessee), Dante B. Fenolio (San Antonio Zoo)