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Picrodon
''Picrodon'' is the name given to a genus of archosaur, possibly a sauropodomorph dinosaur, from the Rhaetian of England which was possibly synonymous with the dubious archosaur ''Avalonianus''. The type, and only species, ''P. herveyi'', was named in 1898.H. G. Seeley. 1898. On large terrestrial saurians from the Rhaetic Beds of Wedmore Hill, described as '' Avalonia sanfordi'' and ''Picrodon herveyi''. Geological Magazine, decade 4 5:1-6 Discovery and naming In 1894, W. A. Sanford described the fossil remains of what he considered to be two large reptiles discovered near Westbury-on-Severn, Glastonbury (Westbury Formation) by Eev. Sydenham H. A. Hervey and Sanford himself.''Proceedings of the Somerset Archaeological Society'' - vol. xl, 1894, p. 234 Harry Govier Seeley described the fossils and named two genera: ''Avalonia'' (preoccupied; now ''Avalonianus'') and ''Picrodon''; both are based solely on teeth. Only a single tooth, holotype BMNH R2875, belonging to ''P. herveyi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Picrodon Tooth Three Angles
''Picrodon'' is the name given to a genus of archosaur, possibly a sauropodomorph dinosaur, from the Rhaetian of England which was possibly synonymous with the dubious archosaur ''Avalonianus''. The type, and only species, ''P. herveyi'', was named in 1898.H. G. Seeley. 1898. On large terrestrial saurians from the Rhaetic Beds of Wedmore Hill, described as '' Avalonia sanfordi'' and ''Picrodon herveyi''. Geological Magazine, decade 4 5:1-6 Discovery and naming In 1894, W. A. Sanford described the fossil remains of what he considered to be two large reptiles discovered near Westbury-on-Severn, Glastonbury (Westbury Formation) by Eev. Sydenham H. A. Hervey and Sanford himself.''Proceedings of the Somerset Archaeological Society'' - vol. xl, 1894, p. 234 Harry Govier Seeley described the fossils and named two genera: ''Avalonia'' (preoccupied; now ''Avalonianus'') and ''Picrodon''; both are based solely on teeth. Only a single tooth, holotype BMNH R2875, belonging to ''P. herveyi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Picrodon
''Picrodon'' is the name given to a genus of archosaur, possibly a sauropodomorph dinosaur, from the Rhaetian of England which was possibly synonymous with the dubious archosaur ''Avalonianus''. The type, and only species, ''P. herveyi'', was named in 1898.H. G. Seeley. 1898. On large terrestrial saurians from the Rhaetic Beds of Wedmore Hill, described as '' Avalonia sanfordi'' and ''Picrodon herveyi''. Geological Magazine, decade 4 5:1-6 Discovery and naming In 1894, W. A. Sanford described the fossil remains of what he considered to be two large reptiles discovered near Westbury-on-Severn, Glastonbury (Westbury Formation) by Eev. Sydenham H. A. Hervey and Sanford himself.''Proceedings of the Somerset Archaeological Society'' - vol. xl, 1894, p. 234 Harry Govier Seeley described the fossils and named two genera: ''Avalonia'' (preoccupied; now ''Avalonianus'') and ''Picrodon''; both are based solely on teeth. Only a single tooth, holotype BMNH R2875, belonging to ''P. herveyi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Avalonianus
''Avalonianus'' is a highly dubious and possibly invalid genus of archosaur from the Late Triassic of England. It was first described in 1898 by Harry Seeley with the name ''Avalonia'',H. G. Seeley. 1898. On large terrestrial saurians from the Rhaetic Beds of Wedmore Hill, described as ''Avalonia sanfordi'' and '' Picrodon herveyi''. Geological Magazine, decade 4 5:1-6 but that name was preoccupied (Walcott, 1889), so Oskar Kuhn renamed it in 1961, albeit with no epithet (although Seeley added the epithet ''sanfordi'' in 1898). It was thought to be a prosauropod, but later analysis revealed it was actually a chimera, with the original teeth coming from a non-dinosaurian ornithosuchian (or possibly an early theropod Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally c ...), and later-refe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Westbury Formation
The Westbury Formation is a geological formation in England, one of the Penarth Group. It dates back to the Rhaetian.Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Triassic, Europe)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 521–525. . The formation is named after the village of Westbury-on-Severn in Gloucestershire. The remains of giant shastasaurids are known from the formation. Vertebrate fauna *''Avalonianus'' *'' Picrodon'' *Shastasauridae indet. See also * List of dinosaur-bearing rock formations This list of dinosaur-bearing rock formations is a list of geologic formations in which dinosaur fossils have been documented. Containing body fossils * List of stratigraphic units with dinosaur body fossils ** List of stratigraphic units with ... References {{Reflist Triassic System of Europe Rhaetian Stage Geologic formations of England ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archosaur
Archosauria () is a clade of diapsids, with birds and crocodilians as the only living representatives. Archosaurs are broadly classified as reptiles, in the cladistic sense of the term which includes birds. Extinct archosaurs include non-avian dinosaurs, pterosaurs, and extinct relatives of crocodilians. Modern paleontologists define Archosauria as a crown group that includes the most recent common ancestor of living birds and crocodilians, and all of its descendants. The base of Archosauria splits into two clades: Pseudosuchia, which includes crocodilians and their extinct relatives, and Avemetatarsalia, which includes birds and their extinct relatives (such as non-avian dinosaurs and pterosaurs). Older definitions of the group Archosauria rely on shared morphological characteristics, such as an antorbital fenestra in the skull, serrated teeth, and an upright stance. Some extinct reptiles, such as proterosuchids and euparkeriids, possessed these features yet originated pri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archosaurs
Archosauria () is a clade of diapsids, with birds and crocodilians as the only living representatives. Archosaurs are broadly classified as reptiles, in the cladistic sense of the term which includes birds. Extinct archosaurs include non-avian dinosaurs, pterosaurs, and extinct relatives of crocodilians. Modern paleontologists define Archosauria as a crown group that includes the most recent common ancestor of living birds and crocodilians, and all of its descendants. The base of Archosauria splits into two clades: Pseudosuchia, which includes crocodilians and their extinct relatives, and Avemetatarsalia, which includes birds and their extinct relatives (such as non-avian dinosaurs and pterosaurs). Older definitions of the group Archosauria rely on shared morphological characteristics, such as an antorbital fenestra in the skull, serrated teeth, and an upright stance. Some extinct reptiles, such as proterosuchids and euparkeriids, possessed these features yet originate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil Taxa Described In 1898
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triassic Archosaurs
The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period of the Mesozoic Era. Both the start and end of the period are marked by major extinction events. The Triassic Period is subdivided into three epochs: Early Triassic, Middle Triassic and Late Triassic. The Triassic began in the wake of the Permian–Triassic extinction event, which left the Earth's biosphere impoverished; it was well into the middle of the Triassic before life recovered its former diversity. Three categories of organisms can be distinguished in the Triassic record: survivors from the extinction event, new groups that flourished briefly, and other new groups that went on to dominate the Mesozoic Era. Reptiles, especially archosaurs, were the chief terrestrial vertebrates during this time. A specialized subgroup of archosaurs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peter Malcolm Galton
Peter Malcolm Galton (born 14 March 1942 in London) is a British vertebrate paleontologist who has to date written or co-written about 190 papers in scientific journals or chapters in paleontology textbooks, especially on ornithischian and prosauropod dinosaurs. With Robert Bakker in a joint article published in ''Nature'' in 1974, he argued that dinosaurs constitute a natural monophyletic group, in contrast to the prevailing view that considered them polyphyletic A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of conver ... as consisting of two different not closely related orders, thus initiating a revolution in dinosaur studies and contributing to the revival of the popularity of dinosaurs in the field of paleontology. Publications * * * Galton, P.M., 1974, "The ornithischian dinosaur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saurian
Sauria is the clade containing the most recent common ancestor of archosaurs (such as crocodilians, dinosaurs, etc.) and lepidosaurs ( lizards and kin), and all its descendants. Since most molecular phylogenies recover turtles as more closely related to archosaurs than to lepidosaurs as part of Archelosauria, Sauria can be considered the crown group of diapsids, or reptiles in general. Depending on the systematics, Sauria includes all modern reptiles or most of them (including birds, a type of archosaur) as well as various extinct groups. Sauria lies within the larger total group Sauropsida, which also contains various stem-reptiles which are more closely related to reptiles than to mammals. Prior to its modern usage, "Sauria" was used as a name for the suborder occupied by lizards, which before 1800 were considered crocodilians. Systematics Recent genomic studiesCrawford, Nicholas G., et al. "More than 1000 ultraconserved elements provide evidence that turtles are the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tooth
A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tearing food, for defensive purposes, to intimidate other animals often including their own, or to carry prey or their young. The roots of teeth are covered by gums. Teeth are not made of bone, but rather of multiple tissues of varying density and hardness that originate from the embryonic germ layer, the ectoderm. The general structure of teeth is similar across the vertebrates, although there is considerable variation in their form and position. The teeth of mammals have deep roots, and this pattern is also found in some fish, and in crocodilians. In most teleost fish, however, the teeth are attached to the outer surface of the bone, while in lizards they are attached to the inner surface of the jaw by one side. In cartilaginous fish, s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
