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Potamobius Astacus
''Astacus'' (from the Greek , ', meaning "lobster" or "crayfish") is a genus of crayfish found in Europe, comprising three extant (living) species and three somewhat contested extinct species. These crayfish are found across Europe and live exclusively in freshwater, mostly inhabiting the bottom of lakes, ponds, and streams. Due to the crayfish plague, crayfish of this genus have declined in many European regions, being replaced by the invasive North American signal crayfish, which carries the plague but is unaffected by it. Classification ''Astacus'' was the first named genus of freshwater crayfish, with many former species later being reassigned to other genera. ''Astacus'' belongs to the family Astacidae, one of the three families of Northern Hemisphere freshwater crayfish within the superfamily Astacoidea. The internal phylogeny of Astacidae can be shown in the cladogram below: Extant species *''Astacus astacus'' (Linnaeus, 1775) - known as the "European crayfish", "nob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astacus Astacus
''Astacus astacus'', the European crayfish, noble crayfish, or broad-fingered crayfish, is the most common species of crayfish in Europe, and a traditional food source. Like other true crayfish, ''A. astacus'' is restricted to fresh water, living only in unpolluted streams, rivers, and lakes. It is found from France throughout Central Europe, to the Balkan Peninsula, and north as far as Scandinavia and Finland, and Eastern Europe. Males may grow up to long, and females up to . Ecology European crayfish feed on worms, aquatic insects, molluscs, and plants. They are nocturnal, spending the day resting in a burrow. They prefer habitats with high levels of shelter availability. The waters they are found in tend to be soft-bottomed with some sand, and they do not tend to be found in muddy water. ''A. astacus'' become sexually mature after three to four years and a series of moults, and breed in October and November. Fertilised eggs are carried by the female, attached to her pleop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crayfish Plague
Crayfish plague (''Aphanomyces astaci'') is a water mold that infects crayfish, most notably the European ''Astacus'' which dies within a few weeks of being infected. When experimentally tested, species from Australia, New Guinea and Japan were also found to be susceptible to the infection. Morphology Crayfish plague invades tissue with hyphae. The hyphae develop sporangia that release amoeboid primary spores, which develop into flagellated secondary zoospores after encystment. The secondary zoospores have two flagella each and can repeatedly encyst before finally reaching a host, attaching and germinating. History Crayfish plague first arrived in Europe in Italy in 1859, either with imported crayfish from North America, or in ballast water discharge. After its original introduction in Italy in 1860, it spread quickly through Europe and was discovered in Sweden in 1907, in Spain in 1972, in Norway in 1971, in Great Britain in 1981, in Turkey in 1984 and in Ireland in 1987. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pontastacus
''Pontastacus'' is a genus of freshwater crayfish native to eastern Europe and western Asia, but also Introduced species, introduced elsewhere. Classification and phylogeny ''Pontastacus'' belongs to the family (biology), family Astacidae, one of the three families of Northern Hemisphere freshwater crayfish within the superfamily (biology), superfamily Astacoidea. The internal phylogeny of Astacidae can be shown in the cladogram below: Species Nine species are recognized: **''Pontastacus cubanicus'' (Birstein & Vinogradov, 1934) - Black Sea, Russia **''Pontastacus danubialis'' Brodsky, 1981 - Danube Delta lakes, Ukraine **''Pontastacus daucinus'' Brodsky, 1981 - Danube Delta lakes, Ukraine and Moldova **''Pontastacus eichwaldi'' (Bott, 1950) - Caspian Sea **''Pontastacus kessleri'' (Schimkewitsch, 1886) - Turkestan **''Pontastacus leptodactylus'' (Eschscholtz, 1823) - around the Black Sea and other aquatic systems in eastern Europe and Turkey; widely introduced elsewhere - "Turk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pacifastacus
''Pacifastacus'' is a genus of crayfish native to western North America (USA and Canada), containing six species, two of which are extinct: *†'' Pacifastacus chenoderma'' (fossil: Miocene – Pliocene) *'' Pacifastacus connectens'' *'' Pacifastacus fortis'' – Shasta crayfish *'' Pacifastacus gambelii'' *''Pacifastacus leniusculus'' – signal crayfish The signal crayfish (''Pacifastacus leniusculus'') is a species of crayfish indigenous to North America. Introduced to Europe in the 1960s to supplement the North European ''Astacus astacus'' fisheries, which were being damaged by crayfish plague ... *†'' Pacifastacus nigrescens'' – Sooty crayfish References Astacidae Crustacean genera {{Crayfish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladogram
A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not show how ancestors are related to descendants, nor does it show how much they have changed, so many differing evolutionary trees can be consistent with the same cladogram. A cladogram uses lines that branch off in different directions ending at a clade, a group of organisms with a last common ancestor. There are many shapes of cladograms but they all have lines that branch off from other lines. The lines can be traced back to where they branch off. These branching off points represent a hypothetical ancestor (not an actual entity) which can be inferred to exhibit the traits shared among the terminal taxa above it. This hypothetical ancestor might then provide clues about the order of evolution of various features, adaptation, and other e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogeny
A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or Taxon, taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA. In other words, it is a branching diagram or a tree (graph theory), tree showing the evolutionary relationships among various biological species or other entities based upon similarities and differences in their physical or genetic characteristics. In evolutionary biology, all life on Earth is theoretically part of a single phylogenetic tree, indicating common ancestry. Phylogenetics is the study of phylogenetic trees. The main challenge is to find a phylogenetic tree representing optimal evolutionary ancestry between a set of species or taxa. computational phylogenetics, Computational phylogenetics (also phylogeny inference) focuses on the algorithms involved in finding optimal phylogenetic tree in the phylogenetic landscape. Phylogene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astacoidea
Astacoidea is superfamily of freshwater crayfish that live in the Northern Hemisphere. The other superfamily of crayfish, Parastacoidea, lives in the Southern Hemisphere. Astacoidea consists of three families: Astacidae (from Europe and western North America), Cambaridae (from eastern North America), and Cambaroididae (from eastern Asia). Crayfish are closely related to lobsters, as shown in the simplified cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ... below. References Crayfish Freshwater crustaceans Crustacean taxonomy Crustacean superfamilies Taxa named by Pierre André Latreille {{Crayfish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superfamily (biology)
In biology, taxonomic rank (which some authors prefer to call nomenclatural rank because ranking is part of nomenclature rather than taxonomy proper, according to some definitions of these terms) is the relative or absolute level of a group of organisms (a ''taxon'') in a hierarchy that reflects evolutionary relationships. Thus, the most inclusive clades (such as Eukarya and Animalia) have the highest ranks, whereas the least inclusive ones (such as ''Homo sapiens'' or '' Bufo bufo'') have the lowest ranks. Ranks can be either relative and be denoted by an indented taxonomy in which the level of indentation reflects the rank, or absolute, in which various terms, such as species, genus, family, order, class, phylum, kingdom, and domain designate rank. This page emphasizes absolute ranks and the rank-based codes (the Zoological Code, the Botanical Code, the Code for Cultivated Plants, the Prokaryotic Code, and thCode for Viruses require them. However, absolute ranks are not r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northern Hemisphere
The Northern Hemisphere is the half of Earth that is north of the equator. For other planets in the Solar System, north is defined by humans as being in the same celestial sphere, celestial hemisphere relative to the invariable plane of the Solar System as Earth's North Pole. Due to Earth's axial tilt of 23.439281°, there is a seasonal variation in the lengths of the day and night. There is also a seasonal variation in temperatures, which lags the variation in day and night. Conventionally, winter in the Northern Hemisphere is taken as the period from the December solstice (typically December 21 UTC) to the March equinox (typically March 20 UTC), while summer is taken as the period from the June solstice through to the September equinox (typically on 23 September UTC). The dates vary each year due to the difference between the calendar year and the Year#Astronomical years, astronomical year. Within the Northern Hemisphere, oceanic currents can change the weather patterns that aff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astacidae
Astacidae is a family (biology), family of freshwater crayfish native to Europe, western Asia and western North America. The family is made up of four extant taxon, extant (living) genera: The genera ''Astacus'' (which includes the European crayfish), ''Pontastacus'' (which includes the Turkish crayfish), and ''Austropotamobius'' are all found throughout Europe and parts of western Asia, while ''Pacifastacus'' (which includes the signal crayfish) is native to western United States and British Columbia, but has also been Introduced species, introduced elsewhere. Classification and phylogeny Astacidae belongs to the superfamily (biology), superfamily Astacoidea, which contains all crayfish in the Northern Hemisphere. Astacoidea is the sister taxon to Parastacoidea, which contains all crayfish of the Southern Hemisphere. Crayfish and lobsters together comprise the infraorder Astacidea, as shown in the simplified cladogram below: The internal phylogeny of Astacidae can be further sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Family (biology)
Family (, : ) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae, but that family is commonly referred to as the "walnut family". The delineation of what constitutes a family—or whether a described family should be acknowledged—is established and decided upon by active taxonomists. There are not strict regulations for outlining or acknowledging a family, yet in the realm of plants, these classifications often rely on both the vegetative and reproductive characteristics of plant species. Taxonomists frequently hold varying perspectives on these descriptions, leading to a lack of widespread consensus within the scientific community ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astacus Astacus 01
''Astacus'' (from the Greek , ', meaning "lobster" or "crayfish") is a genus of crayfish found in Europe, comprising three extant (living) species and three somewhat contested extinct species. These crayfish are found across Europe and live exclusively in freshwater, mostly inhabiting the bottom of lakes, ponds, and streams. Due to the crayfish plague, crayfish of this genus have declined in many European regions, being replaced by the invasive North American signal crayfish, which carries the plague but is unaffected by it. Classification ''Astacus'' was the first named genus of freshwater crayfish, with many former species later being reassigned to other genera. ''Astacus'' belongs to the family Astacidae, one of the three families of Northern Hemisphere freshwater crayfish within the superfamily Astacoidea. The internal phylogeny of Astacidae can be shown in the cladogram below: Extant species *''Astacus astacus'' (Linnaeus, 1775) - known as the "European crayfish", "nob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
