| Cumberland elktoe | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Bivalvia |
| Order: | Unionida |
| Family: | Unionidae |
| Genus: | Alasmidonta |
| Species: | A. atropurpurea |
| Binomial name | |
| Alasmidonta atropurpurea (Rafinesque, 1831) | |
Alasmidonta atropurpurea, common name Cumberland elktoe, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels.
The Cumberland elktoe has a thin, but not fragile, shell. The outside surface of the shell (periostracum) is smooth, somewhat shiny, and covered with greenish rays. Young specimens have a yellowish brown periostracum, while specimens of adults are generally much darker. The inside surface of the shell (nacre) is shiny, with the color being white, bluish white, or sometimes peach or salmon.
The Cumberland elktoe is endemic to the upper Cumberland River system, and it still exists in 12 mostly small tributaries in southeast Kentucky and north-central Tennessee.
The Cumberland elktoe is limited in distribution to the upper Cumberland River system in southeast Kentucky and north-central Tennessee, occupying streams both above and below Cumberland Falls. This species appears to have occurred only in the main stem of the Cumberland River and primarily its southern tributaries upstream from the hypothesized original location of Cumberland Falls near Burnside, Pulaski County, Kentucky. [2] The original type locality was simply "river Cumberland," according to Clarke, [3] who, upon ascertaining that the type specimen was lost, designated a neotype from the Clear Fork, a tributary to the Big South Fork, in Fentress County, Tennessee. All verified sites of occurrence are in the Cumberland Plateau Physiographic Province, giving it one of the most restricted ranges of any Cumberlandian species.
There has been confusion about the historical distribution of this species because of its similarity to a congener - the elktoe ( Alasmidonta marginata ). [2] Museum and literature records of Alasmidonta marginata from the Cumberland River drainage on the Cumberland Plateau should be verified because they may actually represent the Cumberland elktoe. Cicerello and Laudermilk [2] maintains that these two species occur sympatrically in the Rockcastle River, contrary to the assertion by Gordon and Layzer [4] that they are allopatric.
The Cumberland elktoe has apparently been extirpated from the main stem of the Cumberland River and Laurel River and its tributary, Lynn Camp Creek. The status of the Cumberland elktoe from the heavily coal-mined New River watershed, where there is a single known record, [5] is unknown. Based on recent records, populations of the Cumberland elktoe persist in 12 tributaries:
The latter nine streams, which comprise the Big South Fork system, may represent a single metapopulation of the Cumberland elktoe; there may be suitable habitat for the species and/or its fish hosts in intervening stream reaches, potentially allowing for natural genetic interchange to occur.
Considered a "rare species", [3] few sites continue to harbor the Cumberland elktoe. Marsh Creek harbors the largest population known in Kentucky, [6] and the population in Rock Creek is also sizable. [7] In both streams the Cumberland elktoe represented the second most abundant unionid species. [6] [7] The Marsh Creek population, with at least three-year classes present, is viable, but the viability of the Rock Creek population is questionable. [8] The largest population in Tennessee is in the Big South Fork system in the headwaters of the Clear Fork system, where several hundred specimens were found in muskrat middens in the late 1980s. [9] [10] Several age classes of the Cumberland elktoe were represented in samples taken from throughout the larger tributaries of the Big South Fork system in Tennessee during a 1985-86 survey. [9]
This species inhabits medium-sized rivers and may extend into headwater streams where it is often the only mussel present. [5] [11] Gordon and Layzer [11] reported that the species appears to be most abundant in flats, which were described by Gordon [5] as shallow pool areas lacking the bottom contour development of typical pools, with sand and scattered cobble/boulder material, relatively shallow depths, and slow (almost imperceptible) currents. They also report the species from swifter currents and in areas with mud, sand, and gravel substrates.
Gordon and Layzer [4] summarized the reproductive biology and identified fish hosts of the Cumberland elktoe. This anodontine species was found gravid from October through May, but they observed no fish infested with its glochidia until March. They found Cumberland elktoe glochidia to develop equally well on both fin and gill surfaces.
Five native fish species were parasitized by Cumberland elktoe glochidia:
However, under laboratory conditions, juvenile specimens transformed only on the northern hogsucker. [4] The period of glochidial encystment (i.e., until transformation into free-living juveniles) took 24 days, at 66.2° ± 5.4 °F.
The Big South Fork of the Cumberland River is a 76-mile-long (122 km) river in the U.S. states of Tennessee and Kentucky. It is a major drainage feature of the Cumberland Plateau, a major tributary of the Cumberland River system, and the major feature of the Big South Fork National River and Recreation Area.
The dwarf wedgemussel is an endangered species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels.
The Unionidae are a family of freshwater mussels, the largest in the order Unionida, the bivalve molluscs sometimes known as river mussels, or simply as unionids.
Unionida is a monophyletic order of freshwater mussels, aquatic bivalve molluscs. The order includes most of the larger freshwater mussels, including the freshwater pearl mussels. The most common families are the Unionidae and the Margaritiferidae. All have in common a larval stage that is temporarily parasitic on fish, nacreous shells, high in organic matter, that may crack upon drying out, and siphons too short to permit the animal to live deeply buried in sediment.
Alasmidonta is a genus of freshwater mussels, aquatic bivalve mollusks in the family Unionidae, the river mussels.
The Appalachian elktoe is a species of freshwater mussel in the family Unionidae, the river mussels. It is native to the United States, where it is known only from North Carolina and Tennessee.
Cyprogenia is a genus of freshwater mussels, aquatic bivalve mollusks in the family Unionidae.
The fanshell is a species of aquatic bivalve mollusk in the family Unionidae. This clam is native to the United States, where breeding populations remain in only three rivers. It is a federally listed endangered species of the United States.
Dromus dromas, the dromedary pearlymussel or dromedary naiad, is a rare species of freshwater mussel in the family Unionidae. This aquatic bivalve mollusk is native to the Cumberland and Tennessee River systems in the United States, where it has experienced a large population decline. It is a federally listed endangered species of the United States.
Epioblasma is a genus of freshwater mussels, aquatic bivalve mollusks in the family Unionidae, the river mussels. Most of the species in this genus have been lost in modern times, and the entire genus is threatened with the possibility of extinction.
The oyster mussel is a rare species of freshwater mussel in the family Unionidae. This aquatic bivalve mollusk is native to the Cumberland and Tennessee River systems of Kentucky, Tennessee, Alabama, and Virginia in the United States. It has been extirpated from the states of Georgia and North Carolina. It is a federally listed endangered species of the United States.
Lampsilis rafinesqueana, the Neosho mucket or Neosho pearly mussel, is a species of North American freshwater mussel endemic to Arkansas, Oklahoma, Illinois, Missouri and Kansas.
Popenaias popeii, common name the Texas hornshell, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels.
The triangular kidneyshell is a species of freshwater mussel, in the family Unionidae, the river mussels. It is endemic to Alabama in the United States, where it is known from several rivers and streams in the Mobile River Basin. It is a federally listed endangered species of the United States.
Theliderma intermedia, the Cumberland monkeyface pearly mussel or Cumberland monkeyface, is a species of freshwater mussel in the family Unionidae, the river mussels. This aquatic bivalve mollusk is native to Tennessee and Virginia in the United States. Historically widespread in the upper Tennessee River system, it populations have been reduced by habitat destruction and pollution. It now only occurs in two tributaries: the Duck and Powell Rivers. It is a federally listed endangered species.
The glochidium is a microscopic larval stage of some freshwater mussels, aquatic bivalve mollusks in the families Unionidae and Margaritiferidae, the river mussels and European freshwater pearl mussels.
Villosa iris, the rainbow mussel or rainbow-shell, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels.
The South Toe River is a river in Yancey County in Western North Carolina. The name Toe is taken from its original name Estatoe, pronounced 'S - ta - toe', a native American name associated with the Estatoe trade route leading down from the NC mountains through Brevard where there is a historical plaque with information that affirms the route, on into South Carolina where a village of the same name was located.
Fusconaia flava, the Wabash pigtoe, is a freshwater mussel in the family Unionidae.
Megalonaias nervosa is a freshwater mussel species in the family Unionidae. Washboard is the common name used for Megalonaias nervosa.
This article incorporates public domain text (a public domain work of the United States Government) from:
