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Rhizodontidae
Rhizodontida is an extinct group of predatory tetrapodomorphs known from many areas of the world from the Givetian through to the Pennsylvanian - the earliest known species is about 377 million years ago (Mya), the latest around 310 Mya. Rhizodonts lived in tropical rivers and freshwater lakes and were the dominant predators of their age. They reached huge sizes - the largest known species, '' Rhizodus hibberti'' from Europe and North America, was an estimated 7 m in length, making it the largest freshwater fish known. Description The upper jaw had a marginal row of small teeth on the maxilla and premaxilla, medium-sized fangs on the ectopterygoid and dermopalatine bones, and large tusks on the vomers and premaxillae. On the lower jaw were marginal teeth on the dentary, with fangs on the three coronoids and a huge tusk at the symphysial tip of the dentary. Apparently, the left and right mandibles rotated inwards towards each other on biting. This may have been a kinetic mec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrapodomorph
The Tetrapodomorpha (also known as Choanata) are a clade of vertebrates consisting of tetrapods (four-limbed vertebrates) and their closest sarcopterygian relatives that are more closely related to living tetrapods than to living lungfish. Advanced forms transitional between fish and the early labyrinthodonts, such as ''Tiktaalik'', have been referred to as "fishapods" by their discoverers, being half-fish, half-tetrapods, in appearance and limb morphology. The Tetrapodomorpha contains the crown group tetrapods (the last common ancestor of living tetrapods and all of its descendants) and several groups of early stem tetrapods, which includes several groups of related lobe-finned fishes, collectively known as the osteolepiforms. The Tetrapodamorpha minus the crown group Tetrapoda are the Stem Tetrapoda, a paraphyletic unit encompassing the fish to tetrapod transition. Among the characteristics defining tetrapodomorphs are modifications to the fins, notably a humerus with convex h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barameda
''Barameda'' (Indigenous Australian language: "fish trap") is a genus of rhizodont lobe-finned fish which lived during the Tournaisian stage near the start of the Carboniferous period in Australia; fossils of the genus have been reported from the Snowy Plains Formation. The largest member of this genus, ''Barameda decipiens'', reached an estimated length of around , while smallest species, ''B. mitchelli'' is estimated to have length about . Description The ''Barameda'' has an extremely elongated and thick body typical of Carboniferous rhizodonts. It is covered with moderately thin, cycloidal scales, with thick bony plates covering its head and operculum (gill flaps), a tightly fused Skull roof, and extremely prominent, sharp fangs, devoid of serrations or cutting edges. Its scales preserved lateral line. Originally it is estimated to have a typical narrow pectoral fin, however later study shows that had wider pectoral fin like other Carboniferous rhizodonts. Alongside ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sauripterus Taylori
''Sauripterus'' ("lizard wing") is a genus of rhizodont lobe-finned fish Sarcopterygii (; ) — sometimes considered synonymous with Crossopterygii () — is a taxon (traditionally a class or subclass) of the bony fishes known as the lobe-finned fishes. The group Tetrapoda, a mostly terrestrial superclass includ ... that lived during the Devonian period (416-360.7 Ma). This genus was described by J. Hall after its discovery at Powy's Curve in Pennsylvania. References Prehistoric lobe-finned fish genera Devonian fish of North America Rhizodonts {{paleo-lobefinned-fish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strepsodus
''Strepsodus'' is a genus of rhizodont lobe-finned fish Sarcopterygii (; ) — sometimes considered synonymous with Crossopterygii () — is a taxon (traditionally a class or subclass) of the bony fishes known as the lobe-finned fishes. The group Tetrapoda, a mostly terrestrial superclass includ ... that lived during the Carboniferous period. Fossils have been found in North America and Australia. References Prehistoric lobe-finned fish genera Carboniferous fish of North America Prehistoric fish of Australia Rhizodonts {{Carboniferous-animal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Screbinodus
''Screbinodus'' is a genus of rhizodont lobe-finned fish Sarcopterygii (; ) — sometimes considered synonymous with Crossopterygii () — is a taxon (traditionally a class or subclass) of the bony fishes known as the lobe-finned fishes. The group Tetrapoda, a mostly terrestrial superclass includ ... that lived during the Carboniferous period. References Prehistoric lobe-finned fish genera Carboniferous bony fish Rhizodonts {{paleo-lobefinned-fish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Letognathus
''Letognathus'' is a genus of rhizodont tetrapodomorph that lived during the Carboniferous period. Its remains come from the Blue Beach Member of the Horton Bluff Formation, near Hantsport, Nova Scotia. Like most rhizodonts, it was of relatively large size, had a large recurved fang at the symphysis of the lower jaw, and a row of three coronoid fangs along the length of the jaw in addition to its marginal dentition. ''Letognathus'' is important for rhizodont systematics because it retains a number of primitive features, such as ossified Meckel's cartilage, are not found in the genera ''Rhizodus'' and ''Strepsodus''. Taxonomic History The members of the Rhizodontida have nearly all had complex taxonomic historiesJeffery, J.E. 2006. The Carboniferous fish genera ''Strepsodus'' and ''Archichthys'' (Rhizodontida: Sarcopterygii): clarifying 150 years of confusion. ''Palaeontology'' 49: 113-132 due to earlier use of the genus ''Strepsodus'' as a wastebasket taxon. The taxon was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sauripterus
''Sauripterus'' ("lizard wing") is a genus of rhizodont lobe-finned fish Sarcopterygii (; ) — sometimes considered synonymous with Crossopterygii () — is a taxon (traditionally a class or subclass) of the bony fishes known as the lobe-finned fishes. The group Tetrapoda, a mostly terrestrial superclass includ ... that lived during the Devonian period (416-360.7 Ma). This genus was described by J. Hall after its discovery at Powy's Curve in Pennsylvania. References Prehistoric lobe-finned fish genera Devonian fish of North America Rhizodonts {{paleo-lobefinned-fish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premaxilla
The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has been usually termed as the incisive bone. Other terms used for this structure include premaxillary bone or ''os premaxillare'', intermaxillary bone or ''os intermaxillare'', and Goethe's bone. Human anatomy In human anatomy, the premaxilla is referred to as the incisive bone (') and is the part of the maxilla which bears the incisor teeth, and encompasses the anterior nasal spine and alar region. In the nasal cavity, the premaxillary element projects higher than the maxillary element behind. The palatal portion of the premaxilla is a bony plate with a generally transverse orientation. The incisive foramen is bound anteriorly and laterally by the premaxilla and posteriorly by the palatine process of the maxilla. It is formed from t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Givetian
The Givetian is one of two faunal stages in the Middle Devonian Period. It lasted from million years ago to million years ago. It was preceded by the Eifelian Stage and followed by the Frasnian The Frasnian is one of two faunal stages in the Late Devonian Period. It lasted from million years ago to million years ago. It was preceded by the Givetian Stage and followed by the Famennian Stage. Major reef-building was under way during th ... Stage. It is named after the town of Givet in France. The oldest forests occurred during the late Givetian. The lower GSSP is located at Jebel Mech Irdane, Tafilalt, Morocco. Name and definition The Givetian Stage was proposed in 1879 by French geologist Jules Gosselet and was accepted for the higher stage of the Middle Devonian by the Subcommission on Devonian Stratigraphy in 1981. References Further reading * {{Geological history, p, p Middle Devonian Devonian geochronology . Devonian North America ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vomer
The vomer (; lat, vomer, lit=ploughshare) is one of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with the sphenoid, the ethmoid, the left and right palatine bones, and the left and right maxillary bones. The vomer forms the inferior part of the nasal septum in humans, with the superior part formed by the perpendicular plate of the ethmoid bone. The name is derived from the Latin word for a ploughshare and the shape of the bone. In humans The vomer is situated in the median plane, but its anterior portion is frequently bent to one side. It is thin, somewhat quadrilateral in shape, and forms the hinder and lower part of the nasal septum; it has two surfaces and four borders. The surfaces are marked by small furrows for blood vessels, and on each is the nasopalatine groove, which runs obliquely downward and forward, and lodges the nasopalatine nerve and vessels. Borders The ''superior border'', the thickest, presents a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
