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Allosaurids
Allosauridae is an extinct family of medium to large bipedal, carnivorous Allosauroidea, allosauroid theropod dinosaurs from the Late Jurassic. Allosauridae is a fairly old taxonomic group, having been first named by the American paleontologist Othniel Charles Marsh in 1878. Description Allosaurids have a general anatomy typical of other Neotheropoda, neotheropod dinosaurs, contributing to the difficulty in defining the family's membership. A typical 8m specimen of ''Allosaurus fragilis'' had a skull of about 0.85m. The premaxilla has five teeth and the maxilla usually around 16. The dentary also typically has 16 teeth. All teeth are serrated and continuously replaced throughout the life of the animal. Allosaurid skulls are characterized by two sets of crests formed by the nasal and lacrimal bones respectively. These crests would have been covered by keratin sheathes.Madsen, James H., Jr. (1993) [1976]. ''Allosaurus fragilis: A Revised Osteology''. Utah Geological Survey Bulleti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allosaurus Fragilis
''Allosaurus'' ( ) is an extinct genus of theropoda, theropod dinosaur that lived 155 to 145 million years ago during the Late Jurassic Geologic time scale, period (Kimmeridgian to late Tithonian Geologic time scale, ages). The first fossil remains that could definitively be ascribed to this genus were described in 1877 in paleontology, 1877 by Othniel Charles Marsh, Othniel C. Marsh. The name "''Allosaurus''" means "different lizard", alluding to its lightweight , which Marsh believed were unique. The genus has a very complicated Taxonomy (biology), taxonomy and includes at least three valid species, the best known of which is ''A. fragilis''. The bulk of ''Allosaurus'' remains come from North America's Morrison Formation, with material also known from the Alcobaça Formation and Lourinhã Formation in Portugal. It was known for over half of the 20th century as ''Antrodemus'', but a study of the abundant remains from the Cleveland-Lloyd Dinosaur Quarry returned the name "''Al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allosaurus
''Allosaurus'' ( ) is an extinct genus of theropod dinosaur that lived 155 to 145 million years ago during the Late Jurassic period ( Kimmeridgian to late Tithonian ages). The first fossil remains that could definitively be ascribed to this genus were described in 1877 by Othniel C. Marsh. The name "''Allosaurus''" means "different lizard", alluding to its lightweight , which Marsh believed were unique. The genus has a very complicated taxonomy and includes at least three valid species, the best known of which is ''A. fragilis''. The bulk of ''Allosaurus'' remains come from North America's Morrison Formation, with material also known from the Alcobaça Formation and Lourinhã Formation in Portugal. It was known for over half of the 20th century as '' Antrodemus'', but a study of the abundant remains from the Cleveland-Lloyd Dinosaur Quarry returned the name "''Allosaurus''" to prominence. As one of the first well-known theropod dinosaurs, it has long attracted attention ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnegie Museum Of Natural History
The Carnegie Museum of Natural History (abbreviated as CMNH) is a natural history museum in the Oakland (Pittsburgh), Oakland neighborhood of Pittsburgh, Pennsylvania. It was founded by List of people from the Pittsburgh metropolitan area, Pittsburgh-based industrialist Andrew Carnegie in 1896. Housing some 22 million specimens, the museum features one of the most extensive paleontological and entomological collections in the world. Description and history The museum consists of organized into 20 galleries as well as research, library, and office space. It holds some 22 million specimens, of which about 10,000 are on view at any given time and about 1 million are cataloged in online databases. In 2008 it hosted 386,300 admissions and 63,000 school group visits. Museum education staff also actively engage in outreach by traveling to schools all around western Pennsylvania. The museum gained prominence in 1899 when its scientists unearthed the fossils of ''Diplodocus carnegi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebrae
Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal segment and the particular species. The basic configuration of a vertebra varies; the vertebral body (also ''centrum'') is of bone and bears the load of the vertebral column. The upper and lower surfaces of the vertebra body give attachment to the intervertebral discs. The posterior part of a vertebra forms a vertebral arch, in eleven parts, consisting of two pedicles (pedicle of vertebral arch), two laminae, and seven process (anatomy), processes. The laminae give attachment to the ligamenta flava (ligaments of the spine). There are vertebral notches formed from the shape of the pedicles, which form the intervertebral foramina when the vertebrae articulation (anatomy), articulate. These foramina are the entry and exit conduits for the spi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Torvosaurus Tanner DBi
''Torvosaurus'' () is a genus of large megalosaurine theropod dinosaur that lived approximately 165 to 148 million years ago during the Callovian to Tithonian ages of the late Middle and Late Jurassic period in what is now Colorado, Portugal, Germany, and possibly England, Spain, Tanzania, and Uruguay. It contains two currently recognized species, ''Torvosaurus tanneri'' and ''Torvosaurus gurneyi'', plus a third unnamed species from Germany. In 1979, the type species ''Torvosaurus tanneri'' was named. Measuring around long and weighing approximately , ''T. tanneri'' was among the largest terrestrial carnivores in North America during the Late Jurassic. Specimens of ''Torvosaurus gurneyi'' were measured up to in length and in body mass, suggesting that it was much larger than ''T. tanneri'' and was the largest terrestrial carnivore in Europe during the Late Jurassic. Based on bone morphology, ''Torvosaurus'' is thought to have had very powerful short arms. Discovery ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megalosauridae
Megalosauridae is a monophyletic Family (taxonomy), family of Carnivore, carnivorous theropod dinosaurs within the group Megalosauroidea. Appearing in the Middle Jurassic, megalosaurids were among the first major radiation of large theropod dinosaurs. They were a relatively primitive group of basal Tetanurae, tetanurans containing two main subfamilies, Megalosaurinae and Afrovenatorinae, along with the basal genus ''Eustreptospondylus'', an unresolved taxon which differs from both subfamilies. The defining megalosaurid, ''Megalosaurus bucklandii'', was first named and described in 1824 by William Buckland after multiple finds in Stonesfield, Oxfordshire, UK. ''Megalosaurus'' was the first formally described dinosaur and was the basis for the establishment of the clade Dinosauria. It is also one of the largest known Middle Jurassic carnivorous dinosaurs, with the best-preserved femur at 805 mm and a proposed body mass of around 943 kg. Megalosauridae has mainly been reco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinosaurus Aegyptiacus
''Spinosaurus'' (; ) is a genus of large spinosaurid theropod dinosaurs that lived in what now is North Africa during the Cenomanian stage of the Late Cretaceous period, about 100 to 94 million years ago. The genus was known first from Egyptian remains discovered in 1912 and described by German palaeontologist Ernst Stromer in 1915. The original remains were destroyed in World War II, but additional material came to light in the early 21st century. It is unclear whether one or two species are represented in the fossils reported in the scientific literature. The type species ''S. aegyptiacus'' is mainly known from Egypt and Morocco. Although a potential second species, ''S. maroccanus'', has been recovered from Morocco, this dubious species is likely a junior synonym of ''S. aegyptiacus''. Other possible junior synonyms include ''Sigilmassasaurus'' from the Kem Kem beds in Morocco and '' Oxalaia'' from the Alcântara Formation in Brazil, though other researchers propose ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinosauridae
Spinosauridae (or spinosaurids) is a clade or Family (taxonomy), family of tetanuran theropod dinosaurs comprising ten to seventeen known genera. Spinosaurid fossils have been recovered worldwide, including Africa, Europe, South America, and Asia. Their remains have generally been attributed to the Early Cretaceous, Early to early Late Cretaceous. Spinosaurids were large Bipedalism, bipedal carnivores. Their crocodilian-like skulls were long, low, and narrow, bearing conical teeth with reduced or absent Glossary of dinosaur anatomy#serrations, serrations. The tips of their upper and Glossary of dinosaur anatomy#mandible, lower jaws fanned out into a spoon-shaped structure similar to a Rosette (design), rosette, behind which there was a Glossary of dinosaur anatomy#subnarial gap, notch in the upper jaw that the expanded tip of the lower jaw fit into. The Glossary of dinosaur anatomy#bony nostrils, nostrils of spinosaurids were retracted to a position further back on the head than in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metriacanthosauridae
Metriacanthosauridae (Greek for "moderately-spined lizards") is an extinct family of allosauroid theropod dinosaurs that lived in Europe and Asia from the Middle Jurassic to the Early Cretaceous. The family is split into two subgroups: Metriacanthosaurinae, which includes dinosaurs closely related to '' Metriacanthosaurus'', and another group composed of the close relatives of '' Yangchuanosaurus''. Metriacanthosaurids are considered carnosaurs, belonging to the Allosauroidea superfamily. The group includes species of large range in body size. Of their physical traits, most notable are their neural spines.Bailey, Jack Bowman. "Neural Spine Elongation in Dinosaurs: Sailbacks or Buffalo-Backs?" Journal of Paleontology, vol. 71, no. 06, 1997, pp. 1124–1146., doi:10.1017/s0022336000036076. The records of the group are mostly confined to Asia, though ''Metriacanthosaurus'' is known from Europe. Metriacanthosauridae is used as a senior synonym of Sinraptoridae. Diagnostic traits ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraphyly
Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In contrast, a monophyletic grouping (a clade) includes a common ancestor and ''all'' of its descendants. The terms are commonly used in phylogenetics (a subfield of biology) and in the tree model of historical linguistics. Paraphyletic groups are identified by a combination of synapomorphies and symplesiomorphies. If many subgroups are missing from the named group, it is said to be polyparaphyletic. The term received currency during the debates of the 1960s and 1970s accompanying the rise of cladistics, having been coined by zoologist Willi Hennig to apply to well-known taxa like Reptilia (reptiles), which is paraphyletic with respect to birds. Reptilia contains the last common ancestor of reptiles and all descendants of that ancest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnosauria
Carnosauria is an extinct group of carnivorous theropod dinosaurs that lived during the Jurassic and Cretaceous periods. While Carnosauria was historically considered largely synonymous with Allosauroidea, some recent studies have revived Carnosauria as clade including both Allosauroidea and Megalosauroidea (which is sometimes recovered as paraphyletic with respect to Allosauroidea), and thus including the majority of non- coelurosaurian members of theropod clade Tetanurae. Other researchers have found Allosauroidea and Megalosauroidea to be unrelated groups.Cau A. (2024)A Unified Framework for Predatory Dinosaur Macroevolution Bollettino della Società Paleontologica Italiana, 63(1): 1-19. Distinctive characteristics of carnosaurs include large eye sockets, a long narrow skull and modifications of the legs and pelvis such as the thigh (femur) being longer than the shin ( tibia). Carnosaurs first appeared in the Middle Jurassic around , and the last definitive carnosau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolutionary Grade
A grade is a taxon united by a level of morphological or physiological complexity. The term was coined by British biologist Julian Huxley, to contrast with clade, a strictly phylogenetic unit. Phylogenetics The concept of evolutionary grades arises in the context of phylogenetics: the study of the evolutionary history and relationships among or within groups of organisms. These relationships are determined by phylogenetic inference methods that focus on observed heritable traits, such as DNA sequences, protein amino acid sequences, or morphology. The result of such an analysis is a phylogenetic tree—a diagram containing a hypothesis of relationships that reflects the evolutionary history of a group of organisms. Definition of an evolutionary grade An evolutionary grade is a group of species united by morphological or physiological traits, that has given rise to another group that has major differences from the ancestral group's condition, and is thus not considered p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
