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Lepisosteus
''Lepisosteus'' (from Greek ''lepis'' (), 'scale' and ''osteon'' (), 'bone') is a genus of gars in the family Gar, Lepisosteidae. It contains four extant species, found throughout eastern and central North America. It is one of two extant gar genera alongside ''Atractosteus.'' Distribution ''Lepisosteus'' is known to be a freshwater fish. However, they do have the ability to survive in high salinity, and low oxygen water after gulping air. ''Lepisosteus'' prefers to reside in Brackish water, brackish and shallow slow-moving waters, living usually in Shoaling and schooling, schools. The habitat range of this genus ranges on the Eastern coast from the Gulf of Mexico in Florida north to Quebec City, Quebec. Habitats can be found in the Missouri River Valley, Missouri River Basin and Mississippi River System, Mississippi River drainage area, westward in the Rio Grande, Rio Grande River basin of Southern Texas and Northern Mexico. There are also populations in the Great Lakes except ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lepisosteus Bemisi
''Lepisosteus'' (from Greek ''lepis'' (), 'scale' and ''osteon'' (), 'bone') is a genus of gars in the family Lepisosteidae. It contains four extant species, found throughout eastern and central North America. It is one of two extant gar genera alongside ''Atractosteus.'' Distribution ''Lepisosteus'' is known to be a freshwater fish. However, they do have the ability to survive in high salinity, and low oxygen water after gulping air. ''Lepisosteus'' prefers to reside in brackish and shallow slow-moving waters, living usually in schools. The habitat range of this genus ranges on the Eastern coast from the Gulf of Mexico in Florida north to Quebec. Habitats can be found in the Missouri River Basin and Mississippi River drainage area, westward in the Rio Grande River basin of Southern Texas and Northern Mexico. There are also populations in the Great Lakes except for Lake Superior. Their range can occasionally reach out towards the Mobile Bay, Perdido Bay, and Mississippi Sound ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longnose Gar
The longnose gar (''Lepisosteus osseus''), also known as longnose garpike or billy gar, is a ray-finned fish in the family Lepisosteidae. The genus may have been present in North America for about 100 million years. References are made to gars being a primitive group of bony fish because they have retained some primitive features, such as a spiral valve intestine, but they are not primitive in the sense of not being fully developed. They have an olive brown to green, torpedo-shaped body armored with ganoid scales, elongated jaws that form a needle-like snout nearly three times the length of its head, and a row of numerous sharp, cone-shaped teeth on each side of the upper jaw. They typically inhabit freshwater lakes, brackish water near coastal areas, swamps, and sluggish backwaters of rivers and streams. They can breathe both air and water, which allows them to inhabit aquatic environments that are low in oxygen. Longnose gar are found along the east coasts of North and C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lepisosteus Indicus
''Lepisosteus'' ''indicus'', the Indian gar, is an extinct species of gar known from the Late Cretaceous (Maastrichtian) and early Paleocene of India. It is known from a single articulated but poorly-preserved skull and a lost set of vertebrae from the Lameta Formation, in addition to numerous isolated scales and teeth from the Lameta Formation and Intertrappean Beds. Taxonomy It was initially described by Woodward (1890) as a species of unrelated aspidorhynchid fish ('' Belonostomus indicus'') until he reclassified it as a gar in 1909. ''L. indicus'' is generally thought to belong to the genus ''Lepisosteus'', a genus that contains several modern gar species that are found in eastern North America. The presence of this species in India suggests that the genus had a much larger range in prehistoric times, and it is thought to be the easternmost known ''Lepisosteus'' species overall. However, some recent studies suggest that it may be only a stem-member of ''Lepisosteus'', as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atractosteus
''Atractosteus'' (from Greek ''atraktos'' (ἀτρακτὀς), 'spindle' and ''osteon'' (ὀστέον), 'bone') is a genus of gars in the family Lepisosteidae, with three extant species. It is one of two surviving gar genera alongside ''Lepisosteus''. The three surviving species are all widely separated from one another, with ''A. spatula'' being found in the south-central United States, ''A. tropicus'' in southern Mexico and Central America, and ''A. tristoechus'' in Cuba. Although generally inhabiting fresh water, they are tolerant of marine conditions. Evolution The genus first appeared during the Santonian stage of the Late Cretaceous, having diverged from ''Lepisosteus'' earlier in the Cretaceous. It quickly achieved a widespread distribution throughout the rest of the Cretaceous, being known from North America, South America and Europe. ''Atractosteus'' survived the Cretaceous–Paleogene extinction event, Cretaceous-Paleogene extinction event, with one articulated foss ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intertrappean Beds
The Intertrappean Beds are a Late Cretaceous and early Paleogene geologic unit in India. These beds are found as interbeds between Deccan Traps layers, including the slightly older Lameta Formation. They consist a number of different subgroups and formations, and span the Cretaceous–Paleogene boundary. Many mostly fragmentary fossils, especially of small vertebrates, are known from the formation. Indeterminate theropod and pterosaur remains have been recovered from the formation, as well as dinosaur eggs.Weishampel, et al. (2004). "Dinosaur distribution." Pp. 517-607. The mammal genera '' Deccanolestes'', '' Sahnitherium'', '' Bharattherium'', '' Indoclemensia, Indotriconodon'' and'' Kharmerungulatum'' have been recovered from several localities. The Early Eocene-aged Bamanbor locality in Gujarat preserves articulated freshwater fish specimens. A rich plant flora is known from the formation. Stratigraphy Although often thought of as a contemporaneous unit that was for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Scale
A fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most jawed fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as well as possible hydrodynamic advantages. The term ''scale'' derives from the Old French , meaning a shell pod or husk. Scales vary enormously in size, shape, structure, and extent, ranging from strong and rigid armour plates in fishes such as shrimpfishes and boxfishes, to microscopic or absent in fishes such as eels and anglerfishes. The morphology (biology), morphology of a scale can be used to identify the species of fish it came from. Scales originated within the jawless ostracoderms, ancestors to all jawed fishes today. Most bony fishes are covered with the cycloid scales of salmon and carp, or the ctenoid scales of perch, or the ganoid scales of sturgeons and gars. Cartilaginous fishes (sharks and rays) are covered with placoi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yolk Sac
The yolk sac is a membranous wikt:sac, sac attached to an embryo, formed by cells of the hypoblast layer of the bilaminar embryonic disc. This is alternatively called the umbilical vesicle by the Terminologia Embryologica (TE), though ''yolk sac'' is far more widely used. The yolk sac is one of the fetal membranes and is important in early embryonic blood supply. In humans much of it is incorporated into the primordial gut (anatomy), gut during the fourth week of embryonic development. In humans The yolk sac is the first element seen within the gestational sac during pregnancy, usually at three days gestation. The yolk sac is situated on the front (ventral) part of the embryo; it is lined by extra-embryonic endoderm, outside of which is a layer of extra-embryonic mesenchyme, derived from the epiblast. Blood is conveyed to the wall of the yolk sac by the primitive aorta and after circulating through a wide-meshed capillary plexus, is returned by the vitelline veins to the tubul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Fin
Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only by muscles. Fish fins are distinctive anatomical features with varying structures among different clades: in ray-finned fish (Actinopterygii), fins are mainly composed of bony spines or rays covered by a thin stretch of scaleless skin; in lobe-finned fish ( Sarcopterygii) such as coelacanths and lungfish, fins are short rays based around a muscular central bud supported by jointed bones; in cartilaginous fish ( Chondrichthyes) and jawless fish ( Agnatha), fins are fleshy " flippers" supported by a cartilaginous skeleton. Fins at different locations of the fish body serve different purposes, and are divided into two groups: the midsagittal ''unpaired fins'' and the more laterally located ''paired fins''. Unpaired fins are p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorsal Fin
A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found in most fish, in mammals such as whales, and in extinct ancient marine reptiles such as ichthyosaurs. Most have only one dorsal fin, but some have two or three. Wildlife biologists often use the distinctive nicks and wear patterns which develop on the dorsal fins of whales to identify individuals in the field. The bones or cartilages that support the dorsal fin in fish are called pterygiophores. Functions The main purpose of the dorsal fin is usually to stabilize the animal against rolling and to assist in sudden turns. Some species have further adapted their dorsal fins to other uses. The sunfish uses the dorsal fin (and the anal fin Fins are moving appendages protruding from the body of fish that interact with water to ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thanetian
The Thanetian is, in the International Commission on Stratigraphy, ICS Geologic timescale, the latest age (geology), age or uppermost stage (stratigraphy), stratigraphic stage of the Paleocene epoch (geology), Epoch or series (stratigraphy), Series. It spans the time between . The Thanetian is preceded by the Selandian Age and followed by the Ypresian Age (part of the Eocene). The Thanetian is sometimes referred to as the Late Paleocene. Stratigraphic definition The Thanetian was established by Switzerland, Swiss geologist Eugène Renevier in 1873. The Thanetian is named after the Thanet Formation, the oldest Cenozoic deposit of the London Basin, which was first identified in the area of Kent (southern England) known as the Isle of Thanet. The base of the Thanetian Stage is laid at the base of magnetic chronozone C26n. The references profile (Global Boundary Stratotype Section and Point) is in the Zumaia section (43° 18'N, 2° 16'W) at the beach of Itzurun, Pais Vasco, northern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palana Formation
Palana may refer to: * Palana, Bikaner, India * Palana, Kheda, India * Palana, Russia * Palana (river), in Russia * Palana (crater), on Mars See also * Palan (other) {{Geodis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
