A pearl is a hard, glistening object produced within the soft tissue of a living shelled mollusk or another animal, such as fossil conulariids. Just like the shell of a mollusk, a pearl is composed of calcium carbonate in minute crystalline form, which has deposited in concentric layers. The ideal pearl is perfectly round and smooth, but many other shapes, known as baroque pearls, can occur. The finest quality of natural pearls have been highly valued as gemstones and objects of beauty for many centuries. Because of this, pearl has become a metaphor for something rare, fine, admirable and valuable.
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 zebra mussel is a small freshwater mussel. The species was originally native to the lakes of southern Russia and Ukraine, but has been accidentally introduced to numerous other areas and has become an invasive species in many countries worldwide. Since the 1980s, the species has invaded the Great Lakes, Hudson River, and Lake Travis.
The freshwater pearl mussel is an endangered species of freshwater mussel, an aquatic bivalve mollusc in the family Margaritiferidae.
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.
Potamilus metnecktayi, the Salina mucket, is a species of freshwater mussel, an aquatic bivalve mollusc in the family Unionidae, the river mussels.
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.
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.
Leptodea is a genus of freshwater mussels, aquatic bivalve mollusks in the family Unionidae, the river mussels.
Medionidus parvulus, the Coosa moccasinshell, is a rare species of freshwater mussel in the family Unionidae, the river mussels. This aquatic bivalve mollusk is native to Georgia and Tennessee in the United States, and has been extirpated from the state of Alabama. It is a federally listed endangered species of the United States.
Obovaria is a genus of freshwater mussels, aquatic bivalve mollusks in the family Unionidae, the river mussels. There are at least six described species in Obovaria at present, all of which are found in the United States. Obovaria subrotunda is found in Canada as well.
Potamilus alatus, the pink heelsplitter, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, commonly known as the river mussels.
Potamilus is a genus of freshwater mussels, aquatic bivalve mollusks in the family Unionidae, the river mussels.
Potamilus amphichaenus, the Texas heelsplitter, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels.
Potamilus capax, the fat pocketbook pearly mussel or fat pocketbook, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels.
Potamilus inflatus, the inflated heelsplitter, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels.
Freshwater bivalves are one kind of freshwater mollusc, along with freshwater snails. They are bivalves which live in freshwater, as opposed to saltwater, the main habitat type for bivalves.
The phrase Alabama heelsplitter has been used as a common name for two different species of American river mussels, freshwater bivalves, both of which can be found in Alabama. The two species are:
Lasmigona alabamensis, common name Alabama heelsplitter, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae.
Leptodea fragilis, the fragile papershell, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. L. fragilis is one of the fastest-growing unionid species and the most abundant unionid species in Lake Erie. Its light-shelled morphology suggests an adaptation to deep water within lakes.
