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Eugeneodontiformes
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] |
Caseodontoidea
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chondrichthyes
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 deepwat ... [...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] |
Late Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, where rocks from this period were first studied. The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. The arthropod groups of myriapods, arachnids and hexapods also became well-established early in this period, after starting their expansion to land at least from the Ordovician period. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The placoderms began dominating al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caseodus
''Caseodus'' is an extinct genus of eugeneodontid holocephalian from the Carboniferous of the United States (Illinois, Indiana, Kansas, South Dakota) and the Early Triassic of Canada (British Columbia). It was of medium size, measuring in length. Eugeneodontida are an extinct order of Chondrichthyes. They are characterized by the presence of tooth whorls. They include iconic genera, such as ''Helicoprion'' ("buzz-saw shark"), ''Ornithoprion'', '' Edestus'' or '' Fadenia''. ''Caseodus'' is one of the few eugeneodontid genera that survived the end-Permian mass extinction event. It is one of the last surviving genera of this clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, .... ''Caseodus'' is named after the late paleoichthyologist Gerard Case. References * Caseodo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fadenia
''Fadenia'' is an extinct genus of eugeneodontid holocephalian chondrichthyan from the Carboniferous Period of Missouri (United States), the Permian period of Greenland, and the Early Triassic epoch of Greenland and Sulphur Mountain Formation of British Columbia, Canada. Eugeneodontida are an extinct order of Chondrichthyes. They are characterized by the presence of tooth whorls. They include iconic genera, such as ''Helicoprion'' (buzz-saw shark), '' Ornithoprion'', '' Edestus'' or '' Caseodus''. ''Fadenia'' is one of the few eugeneodontid genera that survived the end-Permian mass extinction event. It is one of the last surviving genera of this clade. It could reach about in length. The first fossils of Fadenia were discovered and written about in the periodical Meddelelser om Grønland in 1932 by the Danish vertebrate palaeontologist Eigil Nielsen after studying the Upper Permian beds of Cape Stosch, in the fjord of Godthab Gulf in King Christian X Land, Greenland. He had ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ornithoprion
''Ornithoprion'' is an extinct genus of eugeneodont holocephalan closely related to '' Caseodus.'' It lived in the Moscovian stage of the Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonifero ... from 315.2 to 307 million years ago. Various species had an elongated lower jaw. The discovery and description of ''Ornithoprion'' helped establish many aspects of eugeneodont skull anatomy, which previously could only be gleaned from tooth data. References Carboniferous fish of North America Carboniferous cartilaginous fish Prehistoric cartilaginous fish genera {{Paleo-cartilaginous-fish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bobbodus
''Bobbodus'' is an extinct genus of eugeneodont shark from the Carboniferous and Permian periods. ''B. schaefferi'' is the type species and is known from three specimens, all from what was the eastern coast of the Panthallasic Ocean. They were found in the Kasimovian of Iowa, Gzhelian of Nebraska, Asselian of Kansas. Specimens of this species show the partial upper and lower dentition, the palatoquadrate, and gill arch. ''B. xerxesi'' is known from a single tooth found in Wuchiapingian-aged deposits in the Baghuk Mountains of central Iran Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni .... It is named for Xerxes, a famous Archaemenid ruler from the area whose monuments impressed the first author of the paper describing it.Hampe, O., Hairapetian, V., Dorka, M., Witzmann, F., Akb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Romerodus
''Romerodus'' is an extinct genus of eugeneodontid holocephalian from the Carboniferous of North America. Fossils have been found in Nebraska Nebraska () is a state in the Midwestern region of the United States. It is bordered by South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Kansas to the south; Colorado to the southwe .... References Caseodontidae Animals described in 1981 {{paleo-cartilaginous-fish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
