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Edestidae
The Edestidae are a poorly known, extinct family of shark-like eugeneodontid holocephalid cartilaginous fish. Similar to the related family Helicoprionidae, members of this family possessed a unique "tooth-whorl" on the symphysis of the lower jaw and pectoral fins supported by long radials. In addition to having a tooth-whorl on the lower jaw, at least one species of the genus ''Edestus'' had a second tooth-whorl in the upper jaw. The palatoquadrate was either fused to the skull or reduced. Edestids, along with the rest of the Eugeneodontida, are placed within the Holocephali.Tapanila, L., Pruitt, J., Pradel, A., Wilga, C., Ramsay, J., Schlader, R., Didier, D. 2013. Jaws for a spiral-tooth whorl: CT images reveal novel adaptation and phylogeny in fossil Helicoprion. Biology Letters. 10.1098/rsbl.2013.0057 The family disappeared in the Early Triassic The Early Triassic is the first of three epochs of the Triassic Period of the geologic timescale. It spans the time between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edestidae
The Edestidae are a poorly known, extinct family of shark-like eugeneodontid holocephalid cartilaginous fish. Similar to the related family Helicoprionidae, members of this family possessed a unique "tooth-whorl" on the symphysis of the lower jaw and pectoral fins supported by long radials. In addition to having a tooth-whorl on the lower jaw, at least one species of the genus ''Edestus'' had a second tooth-whorl in the upper jaw. The palatoquadrate was either fused to the skull or reduced. Edestids, along with the rest of the Eugeneodontida, are placed within the Holocephali.Tapanila, L., Pruitt, J., Pradel, A., Wilga, C., Ramsay, J., Schlader, R., Didier, D. 2013. Jaws for a spiral-tooth whorl: CT images reveal novel adaptation and phylogeny in fossil Helicoprion. Biology Letters. 10.1098/rsbl.2013.0057 The family disappeared in the Early Triassic The Early Triassic is the first of three epochs of the Triassic Period of the geologic timescale. It spans the time between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lestrodus
''Lestrodus'' is an extinct genus of edestid fish that lived during the Late Carboniferous. It contains one valid species, ''L. newtoni'', which is known from a single tooth whorl from the Millstone Grit of England. It was originally named as a species of ''Edestus ''Edestus'' is an extinct genus of edestoid cartilaginous fish known from the Late Carboniferous ( Pennsylvanian) of the United Kingdom, Russia, and the United States. Most remains consist of isolated curved blades or "whorls" that are studded wi ...'', but is now considered a distinct genus based on morphological differences. References Edestidae Prehistoric animals of Europe Prehistoric cartilaginous fish genera {{Paleo-shark-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eugeneodontid
The Eugeneodontida is an extinct and poorly known order of cartilaginous fishes. They possessed "tooth-whorls" on the symphysis of either the lower or both jaws and pectoral fins supported by long radials. They probably lacked pelvic fins and anal fins. The palatoquadrate was either fused to the skull or reduced. Now determined to be within the Holocephali, their closest living relatives are ratfish. The eugeneodonts are named after paleontologist Eugene S. Richardson, Jr. The Eugeneodontida disappeared in the Early Triassic. Members of the Eugeneodontida are further classified into different families, the most well-preserved members that have been discovered are commonly placed within the families Helicoprionidae ("spiral saws"), and Edestidae ("those which devour"), the former containing the genera ''Helicoprion'', '' Sarcoprion'', and ''Parahelicoprion'', and the latter containing the genera ''Edestus'', ''Lestrodus'', and '' Metaxyacanthus''. All eugeneodonts are thought to h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edestus
''Edestus'' is an extinct genus of edestoid cartilaginous fish known from the Late Carboniferous ( Pennsylvanian) of the United Kingdom, Russia, and the United States. Most remains consist of isolated curved blades or "whorls" that are studded with teeth, that in life were situated within the jaws. ''Edestus'' is a Greek name derived from the word ''edeste'' (to devour), in reference to the aberrant quality and size of the species' teeth. The largest species, ''E. heinrichi'', has been conservatively estimated to reach greater than 6.7 m (22 ft) in length, around the size of the largest known great white shark. Like its other relatives, such as ''Helicoprion'', and unlike modern sharks, the species of ''Edestus'' grew teeth in curved blades or "whorls". In ''Edestus''' case, only a single row of teeth occurred in the midline of each jaw, leading ''Edestus'' to sometimes be described as the "scissor tooth shark". The degree of curvature in the teeth brackets, along with s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edestus Skull Drawing
''Edestus'' is an extinct genus of edestoid cartilaginous fish known from the Late Carboniferous ( Pennsylvanian) of the United Kingdom, Russia, and the United States. Most remains consist of isolated curved blades or "whorls" that are studded with teeth, that in life were situated within the jaws. ''Edestus'' is a Greek name derived from the word ''edeste'' (to devour), in reference to the aberrant quality and size of the species' teeth. The largest species, ''E. heinrichi'', has been conservatively estimated to reach greater than 6.7 m (22 ft) in length, around the size of the largest known great white shark. Like its other relatives, such as ''Helicoprion'', and unlike modern sharks, the species of ''Edestus'' grew teeth in curved blades or "whorls". In ''Edestus''' case, only a single row of teeth occurred in the midline of each jaw, leading ''Edestus'' to sometimes be described as the "scissor tooth shark". The degree of curvature in the teeth brackets, along with s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Carboniferous
Early may refer to: History * The beginning or oldest part of a defined historical period, as opposed to middle or late periods, e.g.: ** Early Christianity ** Early modern Europe Places in the United States * Early, Iowa * Early, Texas * Early Branch, a stream in Missouri * Early County, Georgia Other uses * Early (Scritti Politti album), ''Early'' (Scritti Politti album), 2005 * Early (A Certain Ratio album), ''Early'' (A Certain Ratio album), 2002 * Early (name) * Early effect, an effect in transistor physics * Early Records, a record label * the early part of the morning See also * Earley (other) {{disambiguation, geo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cartilaginous Fish
Chondrichthyes (; ) is a class that contains the cartilaginous fishes that have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or ''bony fishes'', which have skeletons primarily composed of bone tissue. Chondrichthyes are jawed vertebrates with paired fins, paired nares, scales, and a heart with its chambers in series. Extant chondrichthyes range in size from the 10 cm (3.9 in) finless sleeper ray to the 10 m (32 ft) whale shark. The class is divided into two subclasses: Elasmobranchii (sharks, rays, skates, and sawfish) and Holocephali ( chimaeras, sometimes called ghost sharks, which are sometimes separated into their own class). Within the infraphylum Gnathostomata, cartilaginous fishes are distinct from all other jawed vertebrates. Anatomy Skeleton The skeleton is cartilaginous. The notochord is gradually replaced by a vertebral column during development, except in Holocephali, where the notochord stays intact. In some deepw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holocephali
Holocephali ("complete heads"), sometimes given the term Euchondrocephali, is a subclass of cartilaginous fish in the class Chondrichthyes. The earliest fossils are of teeth and come from the Devonian period. Little is known about these primitive forms, and the only surviving group in the subclass is the order Chimaeriformes. Chimaeriformes, commonly known as chimaeras, includes the rat fishes in the genus '' Chimaera'', and the elephant fishes in the genus ''Callorhinchus''. These fishes move by using sweeping movements of their large pectoral fins. They are deep sea fish with slender tails, living close to the seabed to feed on benthic invertebrates. They lack a stomach, their food moving directly into the intestine. Extinct holocephalans were much more diverse in lifestyles, including shark-like predatory forms and slow, durophagous fish. Characteristics Members of this taxon preserve today some features of elasmobranch life in Paleozoic times, though in other respects th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palatoquadrate
In some fishes, the palatoquadrate is the dorsal component of the mandibular arch, the ventral one being Meckel's cartilage. The palatoquadrate forms from splanchnocranium in various chordates including placoderms and acanthodians. See also * Hyomandibula * Fish anatomy * Helicoprion ''Helicoprion'' is an extinct genus of shark-like eugeneodont fish. Almost all fossil specimens are of spirally arranged clusters of the individuals' teeth, called "tooth whorls", which in life were embedded in the lower jaw. As with most extin ... References * Fish anatomy {{paleo-fish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symphysis
A symphysis (, pl. symphyses) is a fibrocartilaginous fusion between two bones. It is a type of cartilaginous joint, specifically a secondary cartilaginous joint. # A symphysis is an amphiarthrosis, a slightly movable joint. # A growing together of parts or structures. Unlike synchondroses, symphyses are permanent. Examples The more prominent symphyses are: * the pubic symphysis * sacrococcygeal symphysis * intervertebral disc between two vertebrae * in the sternum, between the manubrium and body Body may refer to: In science * Physical body, an object in physics that represents a large amount, has mass or takes up space * Body (biology), the physical material of an organism * Body plan, the physical features shared by a group of anima ... * mandibular symphysis, in the jaw Symphysis disorders Pubic symphysis diastasis Pubic symphysis diastasis, is an extremely rare complication that occurs in women who are giving birth. Separation of the two pubic bones during deli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helicoprionidae
The Helicoprionidae, also known as the Agassizodontidae are an extinct, poorly known family of bizarre holocephalids within the poorly understood order Eugeneodontida. Members of the Helicoprionidae possessed a unique "tooth-whorl" on the symphysis of the lower jaw and pectoral fins supported by long radials. The closest living relatives of the Helicoprionidae and all other eugeneodontids are the ratfishes. The anatomy of the tooth-whorl differed amongst genus and species, some possessing complete spirals (such as those of ''Helicoprion ''Helicoprion'' is an extinct genus of shark-like eugeneodont fish. Almost all fossil specimens are of spirally arranged clusters of the individuals' teeth, called "tooth whorls", which in life were embedded in the lower jaw. As with most extin ...''), others possessing halved spirals (seen in '' Parahelicoprion''), and some with wedged half-spirals (seen in '' Sarcoprion''). Each tooth-whorl is thought to be adapted to a different type of p ... [...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] |
