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Troodon
''Troodon'' ( ; ''Troödon'' in older sources) is a wastebasket taxon and a dubious genus of relatively small, bird-like dinosaurs known definitively from the Campanian age of the Late Cretaceous period (about 77 mya). It includes at least one species, ''Troodon formosus'', known from Montana. Discovered in October 1855, ''T. formosus'' was among the first dinosaurs found in North America, although it was thought to be a lizard until 1877. Several well-known troodontid specimens from the Dinosaur Park Formation in Alberta were once believed to be members of this genus. However, recent analyses in 2017 have found the genus to be undiagnostic and referred some of these specimens to the genus '' Stenonychosaurus'' (long believed to be synonymous with ''Troodon'') and others to the genus '' Latenivenatrix''. The genus name is Ancient Greek for "wounding tooth", referring to the teeth, which were different from those of most other theropods known at the time of their discovery. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Troodon Formosus
''Troodon'' ( ; ''Troödon'' in older sources) is a wastebasket taxon and a dubious genus of relatively small, bird-like dinosaurs known definitively from the Campanian age of the Late Cretaceous period (about 77 mya). It includes at least one species, ''Troodon formosus'', known from Montana. Discovered in October 1855, ''T. formosus'' was among the first dinosaurs found in North America, although it was thought to be a lizard until 1877. Several well-known troodontid specimens from the Dinosaur Park Formation in Alberta were once believed to be members of this genus. However, recent analyses in 2017 have found the genus to be undiagnostic and referred some of these specimens to the genus '' Stenonychosaurus'' (long believed to be synonymous with ''Troodon'') and others to the genus '' Latenivenatrix''. The genus name is Ancient Greek for "wounding tooth", referring to the teeth, which were different from those of most other theropods known at the time of their discovery. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Troodontidae
Troodontidae is a clade of bird-like theropod dinosaurs. During most of the 20th century, troodontid fossils were few and incomplete and they have therefore been allied, at various times, with many dinosaurian lineages. More recent fossil discoveries of complete and articulated specimens (including specimens which preserve feathers, eggs, embryos, and complete juveniles), have helped to increase understanding about this group. Anatomical studies, particularly studies of the most primitive troodontids, like ''Sinovenator'', demonstrate striking anatomical similarities with ''Archaeopteryx'' and primitive dromaeosaurids, and demonstrate that they are relatives comprising a clade called Paraves. Description Troodontids are a group of small, bird-like, gracile maniraptorans. All troodontids have unique features of the skull, such as large numbers of closely spaced teeth in the lower jaw. Troodontids have sickle-claws and raptorial hands, and some of the highest non-avian encephali ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stenonychosaurus
''Stenonychosaurus'' (meaning "narrow claw lizard") is a genus of troodontid dinosaur from the Late Cretaceous Dinosaur Park Formation of Alberta, Canada, as well as possibly the Two Medicine Formation. The type and only species, ''S. inequalis'', was named by Charles Mortram Sternberg in 1932, based on a foot, fragments of a hand, and some caudal vertebrae from the Late Cretaceous of Alberta. ''S. inequalis'' was reassigned in 1987 by Phil Currie to the genus ''Troodon'', which was reverted by the recognition of ''Stenonychosaurus'' as a separate genus from the possibly dubious ''Troodon'' in 2017 by Evans ''et al.'' and also later in the same year by Van der Reest and Currie. History of discovery The first specimens currently assigned to ''Troodon'' that were not teeth were both found by Sternberg in 1928, in the Dinosaur Park Formation of Alberta. The first was named ''Stenonychosaurus inequalis'' by Sternberg in 1932, based on a foot, fragments of a hand, and some tail ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stegoceras
''Stegoceras'' is a genus of pachycephalosaurid (dome-headed) dinosaur that lived in what is now North America during the Late Cretaceous period, about 77.5 to 74 million years ago (mya). The first specimens from Alberta, Canada, were described in 1902, and the type species ''Stegoceras validum'' was based on these remains. The generic name means "horn roof", and the specific name means "strong". Several other species have been placed in the genus over the years, but these have since been moved to other genera or deemed junior synonyms. Currently only ''S. validum'' and ''S. novomexicanum'', named in 2011 from fossils found in New Mexico, remain. The validity of the latter species has also been debated. ''Stegoceras'' was a small, bipedal dinosaur about long, and weighed around . The skull was roughly triangular with a short snout, and had a thick, broad, and relatively smooth dome on the top. The back of the skull had a thick "shelf" over the occiput, and it had a thick r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latenivenatrix
''Latenivenatrix'' (meaning "hiding huntress") is a genus of troodontid known from one species, ''L. mcmasterae''. Along with the contemporary ''Stenonychosaurus'', it is known from the non-tooth fossils formerly assigned to the genus ''Troodon''. Although described as separate, it has been considered a junior synonym of ''Stenonychosaurus''. Discovery and specimens The type specimen or holotype of ''Latenivenatrix'', CMN 12340, was originally described in 1969 by Dale Alan Russell and referred by him to the genus ''Stenonychosaurus''. In 1987 it was referred to ''Troodon''. It had been collected in 1968 by Irene Vanderloh in the Dinosaur Park Formation strata from Alberta, southern Canada. The specimen has preserved some skull bones ( frontals, parietals, postorbital, basioccipital and basisphenoid), four vertebrae and four ribs, some chevrons and gastralia, fairly complete forelimb and incomplete hindlimbs. Moreover, three additional specimens coming from the same locality ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is the subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 mya; their dominance continued throughout the Jurassic and Cretaceous periods. The fossil record shows that birds are feathered dinosaurs, having evolved from earlier theropods during the Late Jurassic epoch, and are the only dinosaur lineage known to have survived the Cretaceous–Paleogene extinction event approximately 66 mya. Dinosaurs can therefore be divided into avian dinosaurs—birds—and the extinct non-avian dinosaurs, which are all dinosaurs other than birds. Dinosaurs are varied from taxonomic, morphological and ecological standpoints. Birds, at over 10,700 living species, ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 carnivorous, although a number of theropod groups evolved to become herbivores and omnivores. Theropods first appeared during the Carnian age of the late Triassic period 231.4 million years ago ( Ma) and included all the large terrestrial carnivores from the Early Jurassic until at least the close of the Cretaceous, about 66 Ma. In the Jurassic, birds evolved from small specialized coelurosaurian theropods, and are today represented by about 10,500 living species. Biology Diet and teeth Theropods exhibit a wide range of diets, from insectivores to herbivores and carnivores. Strict carnivory has always been considered the ancestral diet for theropods as a group, and a wider variety of diets was historically considered a character ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinosaur Park Formation
The Dinosaur Park Formation is the uppermost member of the Belly River Group (also known as the Judith River Group), a major geologic unit in southern Alberta. It was deposited during the Campanian stage of the Late Cretaceous, between about 76.5 and 74.4 million years ago. It was deposited in alluvial plain, alluvial and coastal plain environments, and it is bounded by the nonmarine Oldman Formation below it and the marine (ocean), marine Bearpaw Formation above it.Eberth, D.A. 2005. The geology. In: Currie, P.J., and Koppelhus, E.B. (eds), Dinosaur Provincial Park: A Spectacular Ancient Ecosystem Revealed. Indiana University Press: Bloomington and Indianapolis, p.54-82. . The Dinosaur Park Formation contains dense concentrations of dinosaur skeletons, both articulated and disarticulated, which are often found with preserved remains of soft tissues. Remains of other animals such as fish, turtles, and crocodilians, as well as plant remains, are also abundant. The formation h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton. Birds live worldwide and range in size from the bee hummingbird to the ostrich. There are about ten thousand living species, more than half of which are passerine, or "perching" birds. Birds have whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds. Wings, which are modified forelimbs, gave birds the ability to fly, although further evolution has led to the loss of flight in some birds, including ratites, penguins, and diverse endemic island species. The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds, have further evolved for swim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Judith River Formation
The Judith River Formation is a fossil-bearing geologic formation in Montana, and is part of the Judith River Group. It dates to the Late Cretaceous, between 79 and 75.3 million years ago, corresponding to the "Judithian" land vertebrate age. It was laid down during the same time period as portions of the Two Medicine Formation of MontanaSullivan, R.M. and Lucas, S. G. (2006). "The Kirtlandian land-vertebrate "age"–faunal composition, temporal position and biostratigraphic correlation in the nonmarine Upper Cretaceous of western North America." Pp. 7-29 in Lucas, S. G. and Sullivan, R.M. (eds.), ''Late Cretaceous vertebrates from the Western Interior. New Mexico Museum of Natural History and Science Bulletin 35''. and the Oldman Formation of Alberta. It is an historically important formation, explored by early American paleontologists such as Edward Drinker Cope, who named several dinosaurs from scrappy remains found here on his 1876 expedition (such as '' Monoclonius''). Mod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1856 In Paleontology
Insects Vertebrates Conodonts Archosauromorphs Newly named phytosaurs Newly named pseudosuchians Newly named dinosaurs References {{reflist, 30em 1850s in paleontology Paleontology, 1856 In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joseph Leidy
Joseph Mellick Leidy (September 9, 1823 – April 30, 1891) was an American paleontologist, parasitologist and anatomist. Leidy was professor of anatomy at the University of Pennsylvania, later was a professor of natural history at Swarthmore College and the director of scientific and educational programs at the Wagner Free Institute of Science. His book ''Extinct Fauna of Dakota and Nebraska'' (1869) contained many species not previously described and many previously unknown on the North American continent. At the time, scientific investigation was largely the province of wealthy amateurs. The Leidy Glacier in northwest Greenland was named by Robert Peary after him. Early life and family Joseph Leidy was born on September 9, 1823, to an established Philadelphia family of Pennsylvania Germans. His father, Philip, was a hatter; his mother, Catharine, died during childbirth when he was young. His father then married his wife's first cousin, Christiana Mellick. Leidy also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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