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Megamouth
The megamouth shark (''Megachasma pelagios'') is a species of deepwater shark. It is rarely seen by humans and is the smallest of the three extant filter-feeding sharks alongside the relatively larger whale shark and basking shark. Since its discovery in 1976, fewer than 100 specimens have been observed or caught. Like the other two planktivorous sharks, it swims with its mouth wide open, filtering water for plankton and jellyfish. It is recognizable from its large head with rubbery lips. The megamouth is so unlike any other type of shark that it is usually considered to be the sole extant species in the family Megachasmidae, though some scientists have suggested it may belong in the family Cetorhinidae. Description The appearance of the megamouth is distinctive, but little else is known about it. It has a brownish-black colour on top, is white underneath, and has an asymmetrical tail with a long upper lobe, similar to that of the thresher shark. The interior of its gill slits a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megamouth Shark Japan2
The megamouth shark (''Megachasma pelagios'') is a species of deepwater shark. It is rarely seen by humans and is the smallest of the three extant filter-feeding sharks alongside the relatively larger whale shark and basking shark. Since its discovery in 1976, fewer than 100 specimens have been observed or caught. Like the other two planktivorous sharks, it swims with its mouth wide open, filtering water for plankton and jellyfish. It is recognizable from its large head with rubbery lips. The megamouth is so unlike any other type of shark that it is usually considered to be the sole extant species in the family Megachasmidae, though some scientists have suggested it may belong in the family Cetorhinidae. Description The appearance of the megamouth is distinctive, but little else is known about it. It has a brownish-black colour on top, is white underneath, and has an asymmetrical tail with a long upper lobe, similar to that of the thresher shark. The interior of its gill slits a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megachasma Pelagios
The megamouth shark (''Megachasma pelagios'') is a species of deepwater shark. It is rarely seen by humans and is the smallest of the three extant filter-feeding sharks alongside the relatively larger whale shark and basking shark. Since its discovery in 1976, fewer than 100 specimens have been observed or caught. Like the other two planktivorous sharks, it swims with its mouth wide open, filtering water for plankton and jellyfish. It is recognizable from its large head with rubbery lips. The megamouth is so unlike any other type of shark that it is usually considered to be the sole extant species in the family Megachasmidae, though some scientists have suggested it may belong in the family Cetorhinidae. Description The appearance of the megamouth is distinctive, but little else is known about it. It has a brownish-black colour on top, is white underneath, and has an asymmetrical tail with a long upper lobe, similar to that of the thresher shark. The interior of its gill slits a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megachasma Alisonae
''Megachasma alisonae'' is an extinct species of megamouth shark that lived during the Eocene (Priabonian, ca. 36 mya). It is the oldest fossil record of a megamouth shark. The type fossil was recovered from the Søvind Marl Formation in Denmark and consists of a single tooth. Based on comparison with the teeth of the recent megamouth species (''Megachasma pelagios''), the length of the animal has been estimated at . Discovery and naming The holotype and only known specimen of ''M. alisonae'' is NHMUK PV P73711, an isolated tooth. It is nearly complete and either belonged to the right side of the upper jaw or the left side of the lower jaw. It was discovered on a sea cliff in the Pyt Member of the Søvind Marl Formation in Denmark. The tooth was discovered in a bulk sediment sample from the upper of the member that was collected in 1988. The species was described by Kenshu Shimada and David J. Ward in 2016. The specific name honors Alison Ward, who aided David J. Ward with t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megachasmidae
''Megachasma'' is a genus of sharks. It is usually considered to be the sole genus in the distinct family Megachasmidae, though suggestion has been made that it may belong in the family Cetorhinidae, of which the basking shark is currently the sole extant member. ''Megachasma'' is known from a single living species, ''Megachasma pelagios''. In addition to the living ''M. pelagios'', however, two extinct megamouth species – the Priabonian '' M. alisonae''Shimada, Kenshu, and David J. Ward. "The oldest fossil record of the megamouth shark from the late Eocene of Denmark, and comments on the enigmatic megachasmid origin./ref> and the Oligocene–Miocene '' M. applegatei'' – have also recently been proposed on the basis of fossilized tooth remains. An early ancestor of the recent species ''Megachasma pelagios'' was reported from the early Miocene (Burdigalian) of Belgium. However, the Cretaceous-aged ''M. comanchensis'' has been recently reclassified as an odontas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planktivore
A planktivore is an aquatic organism that feeds on planktonic food, including zooplankton and phytoplankton. Planktivorous organisms encompass a range of some of the planet's smallest to largest multicellular animals in both the present day and in the past billion years; basking sharks and copepods are just two examples of giant and microscopic organisms that feed upon plankton. Planktivory can be an important mechanism of top-down control that contributes to trophic cascades in aquatic and marine systems. There is a tremendous diversity of feeding strategies and behaviors that planktivores utilize to capture prey. Some planktivores utilize tides and currents to migrate between estuaries and coastal waters; other aquatic planktivores reside in lakes or reservoirs where diverse assemblages of plankton are present, or migrate vertically in the water column searching for prey. Planktivore populations can impact the abundance and community composition of planktonic species through thei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megachasma Applegatei
''Megachasma applegatei'' is an extinct species of megamouth shark from the Oligocene to early Miocene (28-23 Mya) of the Western United States. The type fossil was discovered in the San Joaquin Valley The San Joaquin Valley ( ; es, Valle de San Joaquín) is the area of the Central Valley of the U.S. state of California that lies south of the Sacramento–San Joaquin River Delta and is drained by the San Joaquin River. It comprises seven c ... in 1973, but only described in 2014, when the species was named after its discoverer, Shelton Applegate. Description ''Magachasma applegatei'' was described from a single tooth. Based on comparison with the teeth of the recent species (''Megachasma pelagios''), it was approximately 6 m long and, like modern megamouth sharks, probably fed on fish and small planktonic invertebrates both in deep and shallow water habitats. Its teeth had shorter crowns and a pair of side cusplets. References Megachasmidae Prehistoric sharks Fossi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filter-feeding
Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feeding are clams, krill, sponges, baleen whales, and many fish (including some sharks). Some birds, such as flamingos and certain species of duck, are also filter feeders. Filter feeders can play an important role in clarifying water, and are therefore considered ecosystem engineers. They are also important in bioaccumulation and, as a result, as indicator organisms. Fish Most forage fish are filter feeders. For example, the Atlantic menhaden, a type of herring, lives on plankton caught in midwater. Adult menhaden can filter up to four gallons of water a minute and play an important role in clarifying ocean water. They are also a natural check to the deadly red tide. Extensive article on the role of menhaden in the ecosystem and possible resul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basking Shark
The basking shark (''Cetorhinus maximus'') is the second-largest living shark and fish, after the whale shark, and one of three plankton-eating shark species, along with the whale shark and megamouth shark. Adults typically reach in length. It is usually greyish-brown, with mottled skin, with the inside of the mouth being white in color. The caudal fin has a strong lateral keel and a crescent shape. Other common names include bone shark, elephant shark, sail-fish, and sun-fish. In Orkney, it is commonly known as hoe-mother (sometimes contracted to homer), meaning "the mother of the pickled dog-fish". The basking shark is a cosmopolitan migratory species, found in all the world's temperate oceans. A slow-moving filter feeder, its common name derives from its habit of feeding at the surface, appearing to be basking in the warmer water there. It has anatomical adaptations for filter-feeding, such as a greatly enlarged mouth and highly developed gill rakers. Its snout is conic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shark
Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimorpha (or Selachii) and are the sister group to the rays. However, the term "shark" has also been used to refer to all extinct members of Chondrichthyes with a shark-like morphology, such as hybodonts and xenacanths. The oldest modern sharks are known from the Early Jurassic. They range in size from the small dwarf lanternshark (''Etmopterus perryi''), a deep sea species that is only in length, to the whale shark (''Rhincodon typus''), the largest fish in the world, which reaches approximately in length. Sharks are found in all seas and are common to depths up to . They generally do not live in freshwater, although there are a few known exceptions, such as the bull shark and the river shark, which can be found in both seawater and fresh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whale Shark
The whale shark (''Rhincodon typus'') is a slow-moving, filter-feeding carpet shark and the largest known extant fish species. The largest confirmed individual had a length of .McClain CR, Balk MA, Benfield MC, Branch TA, Chen C, Cosgrove J, Dove ADM, Gaskins LC, Helm RR, Hochberg FG, Lee FB, Marshall A, McMurray SE, Schanche C, Stone SN, Thaler AD. 2015. "Sizing ocean giants: patterns of intraspecific size variation in marine megafauna". ''PeerJ'' 3:e715 . The whale shark holds many records for size in the animal kingdom, most notably being by far the largest living nonmammalian vertebrate. It is the sole member of the genus ''Rhincodon'' and the only extant member of the family Rhincodontidae, which belongs to the subclass Elasmobranchii in the class Chondrichthyes. Before 1984 it was classified as ''Rhiniodon'' into Rhinodontidae. The whale shark is found in open waters of the tropical oceans and is rarely found in water below . Studies looking at vertebral growth bands and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gill Raker
Gill rakers in fish are bony or cartilaginous processes that project from the branchial arch (gill arch) and are involved with suspension feeding tiny prey. They are not to be confused with the gill filaments that compose the fleshy part of the gill used for gas exchange. Rakers are usually present in two rows, projecting from both the anterior and posterior side of each gill arch. Rakers are widely varied in number, spacing, and form. By preventing food particles from exiting the spaces between the gill arches, they enable the retention of food particles in filter feeders. The structure and spacing of gill rakers in fish determines the size of food particles trapped, and correlates with feeding behavior. Fish with densely spaced, elongated, comb-like gill rakers are efficient at filtering tiny prey, whereas carnivores and omnivores often have more widely spaced gill rakers with secondary projections. Because gill raker characters often vary between closely related taxa, they are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudomegachasma
''Pseudomegachasma'' ("false Megamouth shark, megamouth") is an extinct genus of Filter feeder, filter-feeding shark that was closely related to the modern sand tiger shark. It is known from Cretaceous strata in Russia and the United States, and is the only known Planktivore, planktivorous Odontaspididae, odontaspid, as well as the oldest known planktivorous Elasmobranchii, elasmobranch. It most likely derived from its closest relative, the Piscivore, piscivorous shark ''Johnlongia''. As its name suggests, it was originally classified under ''Megachasma'', before it was found to be an odontaspid. References Odontaspididae Cretaceous sharks Cenomanian life Cretaceous Russia Fossils of Russia Cretaceous fish of North America Fossils of the United States Fossil taxa described in 2015 {{shark-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
