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Margaritiferidae
Margaritiferidae is a family of medium-sized freshwater mussels, aquatic bivalve molluscs in the order Unionida. Text may have been copied from this source, which is available under Attribution 4.0 International (CC BY 4.0)licence. It is the most threatened of all unionid families. The family is sometimes referred to as the freshwater pearl mussel family, but "freshwater pearl mussel" more often applies to the species ''Margaritifera margaritifera''. The name refers to the thick layer of nacre (mother of pearl) lining the interior of the shell of the species, which enables them to produce pearls. Taxonomy A 2018 study suggested a new phylogeny and systematics of the Margaritiferidae, comprising two subfamilies, Gibbosulinae and Margaritiferinae, and four genera, ''Gibbosula'', ''Cumberlandia'', ''Margaritifera'', and ''Pseudunio''. This family has ancient origins, having diverged from the ancestors of the Unionidae during the Late Triassic with the crown group of the Marga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Margaritifera
''Margaritifera'' is a genus of freshwater mussels, Aquatic animal, aquatic bivalve molluscs in the family Margaritiferidae, the freshwater pearl mussels. MolluscaBase eds. (2021). MolluscaBase. Margaritifera Schumacher, 1815. Accessed through: World Register of Marine Species at: http://marinespecies.org/aphia.php?p=taxdetails&id=571966 on 2021-06-22 Species Species within the genus ''Margaritifera'' include: * ''Margaritifera auricularia'' or ''Pseudunio auricularia'' * ''Margaritifera falcata'' (Augustus Addison Gould, Gould, 1850) * ''Margaritifera hembeli'' (Conrad, 1838) * ''Margaritifera margaritifera'' (Carl Linnaeus, Linnaeus, 10th edition of Systema Naturae, 1758) — Freshwater pearl mussel (includes ''Margaritifera margaritifera durrovensis'' Phillips, 1928) * ''Margaritifera marrianae'' R. I. Johnson, 1983 The following fossil species are known from the mid-Cretaceous of Mongolia, being formerly classified in the genus ''Unio (bivalve), Unio'': * †''Margaritifera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freshwater Pearl Mussel
The freshwater pearl mussel (''Margaritifera margaritifera'') is an endangered species of freshwater mussel, an aquatic bivalve mollusc in the family Margaritiferidae. Although the name "freshwater pearl mussel" is often used for this species, other freshwater mussel species (e.g. ''Margaritifera auricularia'') can also create pearls and some can also be used as a source of mother of pearl. Most cultured pearls today come from ''Hyriopsis'' species in Asia, or ''Amblema'' species in North America, both members of the related family Unionidae; pearls are also found within species in the genus ''Unio''. The interior of the shell of ''Margaritifera margaritifera'' has thick nacre (the inner mother of pearl layer of the shell). This species is capable of making fine-quality pearls, and was historically exploited in the search for pearls from wild sources. In recent times, the Russian malacologist Valeriy Zyuganov received worldwide reputation after he discovered that the pearl m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Margaritifera Margaritifera
The freshwater pearl mussel (''Margaritifera margaritifera'') is an endangered species of freshwater mussel, an aquatic bivalve mollusc in the family Margaritiferidae. Although the name "freshwater pearl mussel" is often used for this species, other freshwater mussel species (e.g. ''Margaritifera auricularia'') can also create pearls and some can also be used as a source of mother of pearl. Most cultured pearls today come from ''Hyriopsis'' species in Asia, or ''Amblema'' species in North America, both members of the related family Unionidae; pearls are also found within species in the genus ''Unio''. The interior of the shell of ''Margaritifera margaritifera'' has thick nacre (the inner mother of pearl layer of the shell). This species is capable of making fine-quality pearls, and was historically exploited in the search for pearls from wild sources. In recent times, the Russian malacologist Valeriy Zyuganov received worldwide reputation after he discovered that the pearl mu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freshwater Mussel
Freshwater bivalves are one kind of freshwater mollusc, along with freshwater snails. They are bivalves that live in fresh water as opposed to salt water, which is the main habitat type for bivalves. The majority of species of bivalve molluscs live in the sea, but in addition, a number of different families live in fresh water (and in some cases, also in brackish water). These families belong to two different evolutionary lineages (freshwater mussels and freshwater clams), and the two groups are not closely related. Freshwater bivalves have a simple morphology that varies among taxa, and are distributed around most regions of the world. Species in the two groups vary greatly in size. Some pea clams (''Pisidium'' species) have an adult size of only 3 mm. In contrast, one of the largest species of freshwater bivalves is the swan mussel, in the family Unionidae; it can grow to a length of 20 cm, and usually lives in lakes or slow rivers. Freshwater pearl mussels are eco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pearl
A pearl is a hard, glistening object produced within the soft tissue (specifically the mantle) 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 (mainly aragonite or a mixture of aragonite and calcite) 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. The most valuable pearls occur spontaneously in the wild, but are extremely rare. These wild pearls are referred to as ''natural'' pearls. ''Cultured'' or ''farmed'' pearls from pearl oysters and freshwater mussels make up the majority of those currently sold. Imitation pearls are also widely s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unionida
Unionida is a monophyletic order of freshwater mussels, aquatic bivalve molluscs.Bieler R., Carter J.G. & Coan E.V. (2010). ''Classification of Bivalve families''. pp. 113–133, in: Bouchet P. & Rocroi J.-P. (2010), ''Nomenclator of Bivalve Families''. Malacologia 52(2): 1–184. 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. Taxonomy Fossil evidence suggests a Permian origin for the order, making it incredibly ancient and a survivor of the Permian-Triassic mass extinction. Morphology The shells of these mussels are variable in shape, but usually equivalve and elongate. They have solid, nacreous valves with a pearly interior, radia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cumberlandia
''Cumberlandia monodonta'' (common name spectaclecase) is a freshwater mussel endemic to the United States. Currently, ''C. monodonta'' is listed as an endangered species by the U.S. Fish and Wildlife Service and the International Union for Conservation of Nature. ''Cumberlandia monodonta'' was first reported in a newspaper titled ''The Disseminator (New Harmony, Ind.)'' by Thomas Say in 1829 under the name ''Unio monodonta''. The spectaclecase was then reclassified into the genus ''Cumberlandia'' by A. E. Ortmann in 1912. ''Cumberlandia monodonta'' has experienced a drastic decline in population due to human activity, resulting in its listing as "Endangered" by the Endangered Species Act and the IUCN. In particular, the construction of dams has caused significant problems that disrupt ''C. monodonta'''s habitat and food supply. The Endangered Species Act classifies ''C. monodonta'' as a highly threatened species with a low potential for recovery. Description Physical charac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bivalve
Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bivalves have no head and they lack some usual molluscan organs, like the radula and the odontophore. They include the clams, oysters, cockles, mussels, scallops, and numerous other families that live in saltwater, as well as a number of families that live in freshwater. The majority are filter feeders. The gills have evolved into ctenidia, specialised organs for feeding and breathing. Most bivalves bury themselves in sediment, where they are relatively safe from predation. Others lie on the sea floor or attach themselves to rocks or other hard surfaces. Some bivalves, such as the scallops and file shells, can swim. The shipworms bore into wood, clay, or stone and live inside these substances. The shell of a bivalve is composed of calc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Jurassic
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations containing land animal fossils include the Forest Marble Formation in England, the Kilmaluag Formation in Scotland,British Geological Survey. 2011Stratigraphic framework for the Middle Jurassic strata of Great Britain and the adjoining continental shelf: research report RR/11/06 British Geological Survey, Keyworth, Nottingham. the Daohugou Beds in China, the Itat Formation in Russia, and the Isalo III Formation of western Madagascar. Paleogeography During the Middle Jurassic Epoch, Pangaea began to separate into Laurasia and Gondwana, and the Atlantic Ocean formed. Eastern Laurasia was tectonically active as the Cimmerian plate continued to collide with Laurasia's southern coast, completely closing the Paleo-Tethys Ocean. A subduction zone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
