Elktoe | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Mollusca |
Class: | Bivalvia |
Order: | Unionida |
Family: | Unionidae |
Genus: | Alasmidonta |
Species: | A. marginata |
Binomial name | |
Alasmidonta marginata Say, 1818 | |
The elktoe (Alasmidonta marginata) is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. This species is found in southeastern Canada and the eastern United States. Like many mussels, it is threatened by water pollution from agriculture, industry, and other development, such as acid mine drainage and sedimentation. It may be extinct in Oklahoma.
The elktoe is a moderately sized mussel of about 4 inches. The shell is thin and triangular-shaped with an inflated center. The anterior end is elongated and round and the border of the shell is marked with fine ridges. The hinge of the two shells, or umbo, is large and located near the center of the shell. The shell is a dull yellowish-green with multiple rays and dark green spots. The interior of the shell is a glossy bluish-white and may have some salmon near the edges and beak [2] . The beak consists of double-looped ridges lined with thin teeth. The elktoe most closely resembles the snuffbox and deertoe, however, both lack a beak and teeth [3] .
The elktoe is most commonly found in small, fast-moving, and shallow rivers, however, it can survive in larger bodies of water. The elktoe prefers a sand or gravel substrate. Substantial populations are found from Northeastern Canada to Arkansas. It is found along the east coast from New York to Virginia but remains inland further South. The majority of the elktoe population is found in Ohio, Indiana, and Illinois [4] . The species was once found in Alabama but is now believed to have been extirpated as there have been no recordings in the past few decades [5]
Like other mussels, the elktoe may live for many decades and up to a century buried in rocks and other sediment [6] . They are mostly sedentary but may use their foot, a muscle on the inside of the shell, to move around by extending and contracting the mussel between the two shells.
The elktoe is a filter feeder and eats mostly bacteria, algae, and other organic matter. Water is drawn into the body through the siphon, and food and oxygen are removed from the water which is then pumped out through the siphon.
Mussels are gonochoristic, meaning there are separate sexes. The elktoe breeds during warm months and females will keep the larval forms, called glochidia, in the marsupia for up to eleven months [7] . Once released, the larva must attach to the gills of a host fish, where they are parasitic on the fish until becoming a juvenile mussel. Juvenile mussels will then live in substrate and filter feed until they develop into adults.
All freshwater mussels in North America have suffered an extreme decline in population growth and increase in extinction rate due to habitat loss, deterioration, fragmentation, and pollution [8] . The elktoe also experiences predation and competition with invasive species. In the Mississippi River, the Zebra mussel will attach in large numbers to native mussels, including the elktoe, and cause suffocation and eventual death. Future conservation efforts should focus on maintaining the natural habitat of the mussels from deterioration and pollution from both industrial and residential points. In addition to protecting the elktoe, the most common host fish must also be protected, such as the White sucker, Rock bass, and Warmouth [9] .
Mussel is the common name used for members of several families of bivalve molluscs, from saltwater and freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other edible clams, which are often more or less rounded or oval.
The dwarf wedgemussel is an endangered species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels.
The freshwater pearl mussel is an endangered species of freshwater mussel, an aquatic bivalve mollusc in the family Margaritiferidae.
The cracking pearlymussel is an endangered species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae.
Alasmidonta atropurpurea, common name Cumberland elktoe, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels.
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.
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.
The brook floater or swollen wedgemussel, Alasmidonta varicosa, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. It measures 25.1 mm to 80.2 mm in length although other research also suggests it rarely exceeds three inches (75 mm).
The Chipola slabshell is a part of the phylum Mollusca and the class Bivalvia. This species has suffered a large decrease with upwards of 75% of habitat lost. It is now confined to only a few remnant sites in small drainages within the Chipola River. The federal Endangered Species Act protects it as a designated threatened species by Florida's Endangered and Threatened Species Rule.
Epioblasma brevidens, the Cumberlandian combshell, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae. This species is endemic to the United States, found mainly in the states of Tennessee and Virginia. This mussel resides in medium-sized streams to large rivers. The combshell is an endangered species and protected under the Endangered Species Act of 1973 (ESA). The combshell is threatened by habitat modifications and pollution.
Fusconaia escambia, the narrow pigtoe, is a freshwater bivalve mussel found in Alabama and northwestern Florida. The narrow pigtoe was first discovered in the Escambia River in Alabama and Florida.
Lampsilis abrupta, the pink mucket or pink mucket pearly mussel, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. This species is endemic to 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.
The Carolina heelsplitter is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae.
Potamilus leptodon, the scaleshell mussel or scale shell, is a species of freshwater mussel in the family Unionidae, the river mussels. This aquatic bivalve mollusk has disappeared from much of its historical range. It is endemic to the United States, where it is now present in four or fewer states; it is only found with any regularity in Missouri. It is a federally listed endangered species of the United States.
Lampsilis fasciola, the wavy-rayed lampmussel, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels.
Obovaria arkansasensis, the Southern Hickorynut, is a species of freshwater mussel, an aquatic bivalve mollusc in the family Unionidae, the river mussels. It lives in the southern United States, and has a complex life history including its larvae being parasitic on a fish host.
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.
Sinanodonta beringiana, the Yukon floater, is a freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels.