Identity
Unique IDELEMENT_GLOBAL.2.116512
Element CodeIMGASK7090
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryInvertebrate Animal
IUCNNear threatened
Endemicendemic to a single nation
KingdomAnimalia
PhylumMollusca
ClassGastropoda
OrderCaenogastropoda
FamilyPleuroceridae
GenusPleurocera
Concept ReferenceTurgeon, D. D., J. F. Quinn, Jr., A. E. Bogan, E. V. Coan, F. G. Hochberg, W. G. Lyons, P. M. Mikkelsen, R. J. Neves, C. F. E. Roper, G. Rosenberg, B. Roth, A. Scheltema, F. G. Thompson, M. Vecchione, and J. D. Williams. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks. 2nd Edition. American Fisheries Society Special Publication 26, Bethesda, Maryland. 526 pp.
Conservation Status
Review Date2012-03-20
Change Date2012-03-20
Edition Date2012-03-20
Edition AuthorsCordeiro, J. (2012); Lydeard, C. (2000)
Range Extent100-1000 square km (about 40-400 square miles)
Number of Occurrences1 - 5
Rank ReasonsThis species is limited to the Holston River in Washington Co., southwestern Virginia; although there is some evidence that it may be exterpated as it has not been seen in over 100 years. This species also occurs in Tennessee in parts of the Tennessee and Holston Rivers. Despite limited range, evidence of recent decline and threat information is lacking. Targeted field surveys are recommended to determine the presence and status of this species in Tennessee and Virginia. Site regeneration and protection is needed where habitats have been degraded in the past from impoundment and other activities.
Range Extent CommentsThis species is limited to the Holston River in Washington Co., southwestern Virginia (Burch and Tottenham 1980; Burch, 1989). In Virginia, it is known from one location in the Holston River in Washington County, but has not been recorded in over 100 years
(Stewart and Dillon, 2004). This species also occurs in Tennessee (P. Johnson, AL DCNR, pers. comm., November 2006). In Tennessee, it is recorded from the upper Holston River; the Ridge and Valley region; and northeast Tennessee (Tennessee Department of Environment & Conservation, pers. comm., 2009).
Occurrences CommentsThis species is limited to the Holston River in Washington Co., southwestern Virginia (Burch and Tottenham, 1980; Burch, 1989) where it has not been seen in over 100 years.. This species also occurs in Tennessee (P. Johnson, AL DCNR, pers. comm., November 2006) as evidenced by Pilsbry and Rhoads (1896) who cite the Tennessee River near Knoxville and Holston River.
Threat Impact CommentsEvidence of decline in existing populations is lacking, however, as in related species impoundment is likely to have been a contributing factor to the present status of this species. For example, in the 1950s three large dams were contructed in a tributary of the Holston River with wide-ranging impacts on the mollusc fauna. This included the
extirpation of 35 species of freshwater mussel and a rise in invasive species (Parmalee and Polhemus 2004). Similar impacts have been observed in the Tennessee River system, the only other habitat of this species. Sedimentation from mining, and pollution from agricultural effluent are also likely to be threats to this species.