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Snakehead (fish)
The snakeheads are members of the freshwater perciform fish family Channidae, native to parts of Africa and Asia. These elongated, predatory fish are distinguished by their long dorsal fins, large mouths, and shiny teeth. They breathe air with gills, which allows them to migrate short distances over land. They have suprabranchial organs, which are primitive forms of labyrinth organs, that develop when they grow older. The two extant genera are ''Channa'' in Asia and ''Parachanna'' in Africa, consisting of more than 50 species. They are valuable as a food source and have become notorious as an intentionally released invasive species. These fish have been kept as pets but as they get larger, people let them go into ponds, lakes, and rivers, making these fish invasive. Description The various species of snakeheads differ greatly in size; dwarf snakeheads, such as ''Channa orientalis'', do not surpass in length. Most other snakeheads reach between . Five species ('' C. argus'', ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene
The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "dawn") and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch. The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isotope Carbon-13, 13C in the atmosphere was exceptionally low in comparison with the more common isotope Carbon-12, 12C. The end is set at a major extinction event called the ''Grande Coupure'' (the "Great Break" in continuity) or the Eocene–Oligocene extinction event, which may be related to the impact of one or more large bolides in Popigai impact structure, Siberia and in what is now ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Channa Orientalis
The Ceylon snakehead (''Channa orientalis'') is a species of snakehead found in freshwater habitats, typically shaded streams, in southwestern Sri Lanka (although occasionally claimed to occur in other countries, this is misidentifications of relatives, usually '' C. gachua'').Conte-Grand, C., Britz, R., Dahanukar, N., Raghavan, R., Pethi-yagoda, R., Tan, H.H., Hadiaty, R.K., Yaakob, N.S. & Rüber, L. (2017). Barcoding snakeheads (Teleostei, Channidae) re-visited: Discovering greater species diversity and resolving perpetuated taxonomic confusions. PLoS ONE, 12 (9): e0184017.SeriouslyFishChanna orientalis Retrieved 12 February 2019. It is evaluated as Vulnerable by the IUCN and some do consider ''C. orientalis'' as a threatened species. Description ''C. orientalis'' has a standard length of up to and is one of the smallest species in the family, making it a dwarf snakehead. It lacks pelvic fins and this distinguishes it from some of its relatives, including ''C. gachua'', a w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tortonian
The Tortonian is in the geologic time scale an age or stage of the late Miocene that spans the time between 11.608 ± 0.005 Ma and 7.246 ± 0.005 Ma (million years ago). It follows the Serravallian and is followed by the Messinian. The Tortonian roughly overlaps with the regional Pannonian Stage of the Paratethys timescale of Central Europe. It also overlaps the upper Astaracian, Vallesian and lower Turolian European land mammal ages, the upper Clarendonian and lower Hemphillian North American land mammal ages and the upper Chasicoan and lower Huayquerian South American land mammal ages. Definition The Tortonian was introduced by Swiss stratigrapher Karl Mayer-Eymar in 1858. It was named after the Italian city of Tortona in the region Piedmont. The base of the Tortonian Stage is at the last common appearance of calcareous nanoplankton '' Discoaster kugleri'' and planktonic foram '' Globigerinoides subquadratus''. It is also associated with the short normal polarized magneti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Burdigalian
The Burdigalian is, in the geologic timescale, an age (geology), age or stage (stratigraphy), stage in the early Miocene. It spans the time between 20.43 ± 0.05 annum, Ma and 15.97 ± 0.05 Ma (million years ago). Preceded by the Aquitanian (stage), Aquitanian, the Burdigalian was the first and longest warming period of the MioceneEdward Petuch, Ph.D. Florida Atlantic University, Department of Geosciences. and is succeeded by the Langhian. Stratigraphic definition The name Burdigalian comes from ''Burdigala'', the Latin name for the city of Bordeaux, France. The Burdigalian Stage was introduced in scientific literature by Charles Depéret in 1892. The base of the Burdigalian is at the first appearance of foram species ''Globigerinoides altiaperturus'' and the top of magnetic chronozone C6An. , an official GSSP for the Burdigalian had not yet been assigned. The top of the Burdigalian (the base of the Langhian) is defined by the first appearance of foram species ''Praeorbulina gl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Eocene
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "dawn") and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch. The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isotope 13C in the atmosphere was exceptionally low in comparison with the more common isotope 12C. The end is set at a major extinction event called the ''Grande Coupure'' (the "Great Break" in continuity) or the Eocene–Oligocene extinction event, which may be related to the impact of one or more large bolides in Siberia and in what is now Chesapeake Bay. As with other geologic periods, the strata that define the start and end of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eochanna Chorlakkiensis
''Eochanna chorlakkiensis'' is an extinct prehistoric snakehead. The fish lived in the Lutetian age of the Middle Eocene (41-48 million years ago) in the area of what is now the Kuldana Formation near Chorlakki, Pakistan Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a population of almost 24 ....Roe, L. J. (1991):Phylogenetic and Ecological Significance of Channidae (Osteichthyes Teleostei) from the Early Eocene Kuldana Formation of Kohat, Pakistan. ''Contributions From The Museum Of Paleontology, The University Of Michigan, VOL. 28, NO. 5, PP. 93-10'' References Channidae Fossil taxa described in 1991 {{Anabantiformes-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ypresian
In the geologic timescale the Ypresian is the oldest age (geology), age or lowest stage (stratigraphy), stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by the Eocene Lutetian Age. The Ypresian is consistent with the lower Eocene. Events The Ypresian Age begins during the throes of the Paleocene–Eocene Thermal Maximum (PETM). The Fur Formation in Denmark, the Messel shales in Germany, the Oise amber of France and Cambay amber of India are of this age. The Eocene Okanagan Highlands are an uplands subtropical to temperate series of lakes from the Ypresian. Stratigraphic definition The Ypresian Stage was introduced in scientific literature by Belgium, Belgian geologist André Hubert Dumont in 1850. The Ypresian is named after the Flanders, Flemish city of Ypres in Belgium (spelled ''Ieper'' in Dutch). The definitions of the original stage were totally different from the modern ones. The Ypresi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carp
Carp are various species of oily freshwater fish from the family Cyprinidae, a very large group of fish native to Europe and Asia. While carp is consumed in many parts of the world, they are generally considered an invasive species in parts of Africa, Australia and most of the United States. Biology The cypriniformes (family Cyprinidae) are traditionally grouped with the Characiformes, Siluriformes, and Gymnotiformes to create the superorder Ostariophysi, since these groups share some common features. These features include being found predominantly in fresh water and possessing Weberian ossicles, an anatomical structure derived from the first five anterior-most vertebrae, and their corresponding ribs and neural crests. The third anterior-most pair of ribs is in contact with the extension of the labyrinth and the posterior with the swim bladder. The function is poorly understood, but this structure is presumed to take part in the transmission of vibrations from the swim bl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mollusk
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is estimated between 60,000 and 100,000 additional species. The proportion of undescribed species is very high. Many taxa remain poorly studied. Molluscs are the largest marine phylum, comprising about 23% of all the named marine organisms. Numerous molluscs also live in freshwater and terrestrial habitats. They are highly diverse, not just in size and anatomical structure, but also in behaviour and habitat. The phylum is typically divided into 7 or 8 taxonomic classes, of which two are entirely extinct. Cephalopod molluscs, such as squid, cuttlefish, and octopuses, are among the most neurologically advanced of all invertebrates—and either the giant squid or the colossal squid is the largest known invertebrate species. The gas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquatic Insect
Aquatic insects or water insects live some portion of their life cycle in the water. They feed in the same ways as other insects. Some ''diving'' insects, such as predatory diving beetles, can hunt for food underwater where land-living insects cannot compete. Breathing One problem that aquatic insects must overcome is how to get oxygen while they are under water. Almost all animals require a source of oxygen to live. Insects draw air into their bodies through spiracles, holes found along the sides of the abdomen. These spiracles are connected to tracheal tubes where oxygen can be absorbed. All aquatic insects have become adapted to their environment with the specialization of these structures ;Aquatic adaptations # Simple diffusion over a relatively thin integument # Temporary use of an air bubble # Extraction of oxygen from water using a plastron or blood gill # Storage of oxygen in hemoglobin molecules in hemolymph # Taking oxygen from surface via breathing tubes ( siph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plankton
Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucial source of food to many small and large aquatic organisms, such as bivalves, fish and whales. Marine plankton include bacteria, archaea, algae, protozoa and drifting or floating animals that inhabit the saltwater of oceans and the brackish waters of estuaries. Freshwater plankton are similar to marine plankton, but are found in the freshwaters of lakes and rivers. Plankton are usually thought of as inhabiting water, but there are also airborne versions, the aeroplankton, that live part of their lives drifting in the atmosphere. These include plant spores, pollen and wind-scattered seeds, as well as microorganisms swept into the air from terrestrial dust storms and oceanic plankton swept into the air ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Channa Striata
''Channa striata'', the striped snakehead, is a species of snakehead fish. It is also known as the common snakehead, chevron snakehead, or snakehead murrel and generally referred simply as mudfish. It is native to South and Southeast Asia, and has been introduced to some Pacific Islands. Reports from Madagascar and Hawaii are misidentifications of '' C. maculata''.USGS, Southeast Ecological Science Center: Channa striata.' Retrieved 27 June 2014. A genetic study published in 2017 indicates that ''C. striata'' is a species complex. Description It is a bony fish with endoskeleton ribcage, grows up to a meter in length, though because of fishing, this size is rarely found in the wild. It has a widespread range covering southern China, Pakistan, most of India, southern Nepal, Bangladesh, Sri Lanka, and most of Southeast Asia. It has more recently been introduced to the outermost parts of Indonesia, the Philippines, and Mauritius. Reports beginning in the early 20th century that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
