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Pisidium Conventus
''Pisidium conventus'', the arctic-alpine pea clam, is a species of freshwater bivalve from the family Sphaeriidae. Description The small (2.2–2.8 mm.) shell is oval in shape and thin and fragile. It is broad and flattened (laterally compressed) with flattened umbos near the midpoint. The colour is yellowish-white and the periostracum (surface) is silky with fine, concentric striation. Ecology ''P. conventus'' is a relict of colder climatic periods found only in deep, cold, upland lakes. Distribution and conservation status * Not listed in IUCN red list – not evaluated (NE) * Germany – endangered (''gefährdet'') * Poland – vulnerable (VU) * Nordic countries: Faroes, Finland, Norway and Sweden (not in Denmark, Iceland) * Great Britain and IrelandRoy Anderson ,2005 An annotated list of the non-marine molluscs of Britain and Ireland Journal of Conchology, 38 (6): 607–637, (published 2005 References External links''Pisidium conventus''at Animalbase taxonomy,s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clessin
Stefan Clessin (13 November 1833, Würzburg – 21 December 1911, Regensburg) was a German malacologist. He served as a military officer, and from 1862 worked for the Bavarian railways. He was an editor of the '' Malakozoologische Blätter'' and made major contributions to Martini and Chemitz' ''Systematisches Conchylien-Cabinet''. He conducted research of fossil mollusks as well as living species. Bibliography * ''Die mollusken-fauna der umgegend von Augsburg'' (1871); Bericht des Naturhistorischen vereins in Augsburg, bd. XXI. * ''Ueber Missbildungen der Mollusken und ihrer Gehäuse'', (1873); Bericht of the Naturhistorischer Verein in Augsburg, 22. * ''Deutsche excursions-mollusken-fauna'', (1876), Nurnberg : Bauer & Raspe. * Clessin S. (1880). "Studien über die Familie der Paludinen". '' Malakozoologische Blätter'' (ser. 2)2: 161-196. * ''Die Molluskenfauna Oesterreich-Ungarns und der Schweiz'', (5 parts, 1887–90), Nürnberg : Bauer & Raspe. Taxa described Clessin na ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature, also sometimes i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freshwater
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include non- salty mineral-rich waters such as chalybeate springs. Fresh water may encompass frozen and meltwater in ice sheets, ice caps, glaciers, snowfields and icebergs, natural precipitations such as rainfall, snowfall, hail/ sleet and graupel, and surface runoffs that form inland bodies of water such as wetlands, ponds, lakes, rivers, streams, as well as groundwater contained in aquifers, subterranean rivers and lakes. Fresh water is the water resource that is of the most and immediate use to humans. Water is critical to the survival of all living organisms. Many organisms can thrive on salt water, but the great majority of higher plants and most insects, amphibians, reptiles, mammals and birds need fresh water to survive. Fresh wa ... [...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] |
Sphaeriidae
Sphaeriidae is a family of small to minute freshwater bivalve molluscs in the order Sphaeriida. In the US, they are commonly known as pea clams or fingernail clams. Heard, William H. 1977. Reproduction of fingernail clams (Sphaeriidae: ''Sphaerium'' and ''Musculium''). Malacologia, 16: 421-455. Genera Genera: * Euperinae ** '' Byssanodonta'' d'Orbigny, 1846 ** ''Eupera'' Bourguignat, 1854 * Sphaeriinae ** ''Afropisidium'' Kuiper, 1962 ** ''Euglesa'' Jenyns, 1832 ** ''Musculium'' Link, 1807 ** '' Odhneripisidium'' Kuiper, 1962 ** ''Pisidium'' C. Pfeiffer, 1821 ** ''Sphaerium'' Scopoli, 1777 * fossils ** †'' Megasphaerioides'' Komatsu, J.-H. Chen & Q.-F. Wang, 2003 ** †'' Protosphaerium'' Hocknull, 2000 ** †'' Sphaericoncha'' Kolesnikov, 1980 Biology and ecology Sphaeriidae are hermaphrodites with internal fertilization. Developing young are incubated within their mother (ovoviviparity), and newborn clams look like miniature copies of the adults. Parasites and/or predat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relict (biology)
In biogeography and paleontology, a relict is a population or taxon of organisms that was more widespread or more diverse in the past. A relictual population is a population currently inhabiting a restricted area whose range was far wider during a previous geologic epoch. Similarly, a relictual taxon is a taxon (e.g. species or other lineage) which is the sole surviving representative of a formerly diverse group. Definition A relict (or relic) plant or animal is a taxon that persists as a remnant of what was once a diverse and widespread population. Relictualism occurs when a widespread habitat or range changes and a small area becomes cut off from the whole. A subset of the population is then confined to the available hospitable area, and survives there while the broader population either shrinks or evolves divergently. This phenomenon differs from endemism in that the range of the population was not always restricted to the local region. In other words, the species or group did n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IUCN Red List
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biological species. It uses a set of precise criteria to evaluate the extinction risk of thousands of species and subspecies. These criteria are relevant to all species and all regions of the world. With its strong scientific base, the IUCN Red List is recognized as the most authoritative guide to the status of biological diversity. A series of Regional Red Lists are produced by countries or organizations, which assess the risk of extinction to species within a political management unit. The aim of the IUCN Red List is to convey the urgency of conservation issues to the public and policy makers, as well as help the international community to reduce species extinction. According to IUCN the formally stated goals of the Red List are to provi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nordic Countries
The Nordic countries (also known as the Nordics or ''Norden''; literal translation, lit. 'the North') are a geographical and cultural region in Northern Europe and the Atlantic Ocean, North Atlantic. It includes the sovereign states of Denmark, Finland, Iceland, Norway and Sweden; the autonomous administrative division, autonomous territories of the Faroe Islands and Greenland; and the autonomous region of Ă…land. The Nordic countries have much in common in their way of life, History of Scandinavia, history, religion and Nordic model, social structure. They have a long history of political unions and other close relations but do not form a singular entity today. The Scandinavism, Scandinavist movement sought to unite Denmark, Norway and Sweden into one country in the 19th century. With the dissolution of the union between Norway and Sweden (Norwegian independence), the independence of Finland in the early 20th century and the 1944 Icelandic constitutional referendum, this move ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Britain
Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the largest European island and the ninth-largest island in the world. It is dominated by a maritime climate with narrow temperature differences between seasons. The 60% smaller island of Ireland is to the west—these islands, along with over 1,000 smaller surrounding islands and named substantial rocks, form the British Isles archipelago. Connected to mainland Europe until 9,000 years ago by a landbridge now known as Doggerland, Great Britain has been inhabited by modern humans for around 30,000 years. In 2011, it had a population of about , making it the world's third-most-populous island after Java in Indonesia and Honshu in Japan. The term "Great Britain" is often used to refer to England, Scotland and Wales, including their component adjoining islands. Great Britain and Northern Ireland now constitute the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ireland
Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Great Britain and Ireland), North Channel, the Irish Sea, and St George's Channel. Ireland is the List of islands of the British Isles, second-largest island of the British Isles, the List of European islands by area, third-largest in Europe, and the List of islands by area, twentieth-largest on Earth. Geopolitically, Ireland is divided between the Republic of Ireland (officially Names of the Irish state, named Ireland), which covers five-sixths of the island, and Northern Ireland, which is part of the United Kingdom. As of 2022, the Irish population analysis, population of the entire island is just over 7 million, with 5.1 million living in the Republic of Ireland and 1.9 million in Northern Ireland, ranking it the List of European islan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animalbase
AnimalBase is a project brought to life in 2004 and is maintained by the University of Göttingen, Germany. The goal of the AnimalBase project is to digitize early zoological literature, provide copyright-free open access to zoological works, and provide manually verified lists of names of zoological genera and species as a free resource for the public. AnimalBase contributed to opening up the classical taxonomic literature, which is considered as useful because access to early literature (especially for the late 18th century) can be difficult for researchers who need the old sources for their taxonomic research. AnimalBase data are public domain. The public use of AnimalBase data is not restricted or conditioned.AnimalBase Project Group, 2005-2010. AnimalBase. Early zoological literature online. World wide web electronic publication http://www.animalbase.uni-goettingen.de accessed 30 July 2010. AnimalBase covers all zoological disciplines. In the field of biodiversity informatics A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pisidium
''Pisidium'' is a genus of very small or minute freshwater clams known as pill clams or pea clams, aquatic bivalve molluscs in the family Sphaeriidae, the pea clams and fingernail clams. In some bivalve classification systems, the family Sphaeriidae is referred to as Pisidiidae, and occasionally ''Pisidium'' species are grouped in a subfamily known as Pisidiinae. ''Pisidium'' and taphonomy In large enough quantities, the minute shells of these bivalves can affect environmental conditions, and this change in conditions can positively affect the ability of organic remains in the immediate environment to fossilize (one aspect of taphonomy). For example, in the Dinosaur Park Formation, the fossil remains of hadrosaur eggshells are rare. This is because the breakdown of tannins from the local coniferous vegetation caused the ancient waters to be acidic, and therefore usually eggshell fragments dissolved in the water before they had a chance to be fossilized. Hadrosaur eggshell fra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
