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Microvenator
''Microvenator'' (meaning "small hunter") is a genus of dinosaur from the Early Cretaceous Cloverly Formation in what is now south central Montana. ''Microvenator'' was an oviraptorosaurian theropod. The holotype fossil is an incomplete skeleton, most likely a juvenile with a length of , and consequently, the adult size remains uncertain. ''Microvenator celer'' is primitive and may be the "sister taxon to all other oviraptorosaurs."Varricchio, D. J. 2001. Late Cretaceous oviraptorosaur (Theropoda) dinosaurs from Montana. pp. 42–57 in D. H. Tanke and K. Carpenter (eds.), Mesozoic Vertebrate Life. Indiana University Press, Indianapolis, Indiana. Discovery Barnum Brown collected the type specimen (AMNH 3041) in 1933 by a field party working for the American Museum of Natural History and he erroneously included ''Deinonychus'' teeth with the specimen. Because of this, Brown informally dubbed it "Megadontosaurus" ("big-toothed lizard"), Brown made illustrations of it, but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microvenator
''Microvenator'' (meaning "small hunter") is a genus of dinosaur from the Early Cretaceous Cloverly Formation in what is now south central Montana. ''Microvenator'' was an oviraptorosaurian theropod. The holotype fossil is an incomplete skeleton, most likely a juvenile with a length of , and consequently, the adult size remains uncertain. ''Microvenator celer'' is primitive and may be the "sister taxon to all other oviraptorosaurs."Varricchio, D. J. 2001. Late Cretaceous oviraptorosaur (Theropoda) dinosaurs from Montana. pp. 42–57 in D. H. Tanke and K. Carpenter (eds.), Mesozoic Vertebrate Life. Indiana University Press, Indianapolis, Indiana. Discovery Barnum Brown collected the type specimen (AMNH 3041) in 1933 by a field party working for the American Museum of Natural History and he erroneously included ''Deinonychus'' teeth with the specimen. Because of this, Brown informally dubbed it "Megadontosaurus" ("big-toothed lizard"), Brown made illustrations of it, but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timeline Of Oviraptorosaur Research
This timeline of oviraptorosaur research is a chronological listing of events in the history of paleontology focused on the oviraptorosaurs, a group of beaked, bird-like theropod dinosaurs. The early history of oviraptorosaur paleontology is characterized by taxonomic confusion due to the unusual characteristics of these dinosaurs. When initially described in 1924 ''Oviraptor'' itself was thought to be a member of the Ornithomimidae, popularly known as the "ostrich" dinosaurs, because both taxa share toothless beaks. Early caenagnathid oviraptorosaur discoveries like ''Caenagnathus'' itself were also incorrectly classified at the time, having been misidentified as birds. The hypothesis that caenagnathids were birds was questioned as early as 1956 by Romer, but not corrected until Osmolska formally reclassified them as dinosaurs in 1976. Meanwhile, the classification of ''Oviraptor'' as an ornithomimid persisted unquestioned by researchers like Romer and Steel until the early ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cloverly Formation
The Cloverly Formation is a geological formation of Early and Late Cretaceous age (Valanginian to Cenomanian stage) that is present in parts of Montana, Wyoming, Colorado and Utah in the western United States. It was named for a post office on the eastern side of the Bighorn Basin in Wyoming by N.H. Darton in 1904. The sedimentary rocks of formation were deposited in floodplain environments and contain vertebrate fossils, including a diverse assemblage of dinosaur remains. In 1973, the Cloverly Formation Site was designated as a National Natural Landmark by the National Park Service. Stratigraphy The Cloverly Formation rests disconformably on the Morrison Formation and is conformably overlain by the Thermopolis Shale. It is subdivided into a variety of members, depending on the location.Moberly, R.M., Jr., 1960, Morrison, Cloverly, and Sykes Mountain formations, northern Bighorn basin, Wyoming and Montana: Geological Society of America Bulletin, v. 71, no. 8, p. 1137-1176. In t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caenagnathids
Caenagnathidae is a family of bird-like maniraptoran theropod dinosaurs from the Cretaceous of North America and Asia. They are a member of the Oviraptorosauria, and close relatives of the Oviraptoridae. Like other oviraptorosaurs, caenagnathids had specialized beaks, long necks, and short tails, and would have been covered in feathers. The relationships of caenagnathids were long a puzzle. The family was originally named by Raymond Martin Sternberg in 1940 as a family of flightless birds. The discovery of skeletons of the related oviraptorids revealed that they were in fact non-avian theropods, and the discovery of more complete caenagnathid remains revealed that ''Chirostenotes pergracilis'', originally named on the basis of a pair of hands, and ''Citipes elegans'', originally thought to be an ornithomimid, named from a foot, were caenagnathids as well. Anatomy Overall, the anatomy of the caenagnathids is similar to that of the closely related Oviraptoridae, but there are a n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tenontosaurus
''Tenontosaurus'' ( ; ) is a genus of medium- to large-sized ornithopod dinosaur. It was a relatively medium sized ornithopod, reaching in length and in body mass. It had an unusually long, broad tail, which like its back was stiffened with a network of bony tendons. The genus is known from the late Aptian to Albian ages of the Early Cretaceous period sediments of western North America, dating between 115 and 108 million years ago. It contains two species, ''Tenontosaurus tilletti'' (described by John Ostrom in 1970) and ''Tenontosaurus dossi'' (described by Winkler, Murry, and Jacobs in 1997). Many specimens of ''T. tilletti'' have been collected from several geological formations throughout western North America. ''T. dossi'' is known from only a handful of specimens collected from the Twin Mountains Formation of Parker County, Texas. History of discovery The first ''Tenontosaurus'' fossil was found in Big Horn County, Montana by an American Museum of Natural Histo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oviraptorosauria
Oviraptorosaurs ("egg thief lizards") are a group of feathered maniraptoran dinosaurs from the Cretaceous Period of what are now Asia and North America. They are distinct for their characteristically short, beaked, parrot-like skulls, with or without bony crests atop the head. They ranged in size from ''Caudipteryx'', which was the size of a turkey, to the 8-meter-long, 1.4-ton ''Gigantoraptor''. The group (along with all maniraptoran dinosaurs) is close to the ancestry of birds. Some researchers such as Maryanska ''et al'' (2002) and Osmólska ''et al.'' (2004) have proposed that they may represent primitive flightless birds.Osmólska, Halszka, Currie, Philip J., Brasbold, Rinchen (2004) "The Dinosauria" Weishampel, Dodson, Osmólska. "Chapter 8 Oviraptorosauria" University of California Press. The most complete oviraptorosaur specimens have been found in Asia. The North American oviraptorosaur record is sparse.Varricchio, D. J. 2001. Late Cretaceous oviraptorosaur (Theropoda) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Ostrom
John Harold Ostrom (February 18, 1928 – July 16, 2005) was an American paleontologist who revolutionized modern understanding of dinosaurs in the 1960s. As first proposed by Thomas Henry Huxley in the 1860s, Ostrom showed that dinosaurs were more like big non-flying birds than they were like lizards (or "saurians"), and even proved that birds themselves are a type of theropod saurischian dinosaur. Since dinosaurs themselves are considered reptiles, Ostrom's work made zoologists question whether birds should be considered an order of Reptilia instead of their own class, Aves. The first of Ostrom's broad-based reviews of the osteology and phylogeny of the primitive bird '' Archaeopteryx'' appeared in 1976. His reaction to the eventual discovery of feathered dinosaurs in China, after years of acrimonious debate, was bittersweet. Early life and career Ostrom was born in New York in 1928 and grew up in Schenectady. As a pre-medical undergraduate student at Union College, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deinonychus
''Deinonychus'' ( ; ) is a genus of dromaeosaurid theropod dinosaur with one described species, ''Deinonychus antirrhopus''. This species, which could grow up to long, lived during the early Cretaceous Period, about 115–108 million years ago (from the mid-Aptian to early Albian stages). Fossils have been recovered from the U.S. states of Montana, Utah, Wyoming, and Oklahoma, in rocks of the Cloverly Formation, Cedar Mountain Formation and Antlers Formation, though teeth that may belong to ''Deinonychus'' have been found much farther east in Maryland. Paleontologist John Ostrom's study of ''Deinonychus'' in the late 1960s revolutionized the way scientists thought about dinosaurs, leading to the " dinosaur renaissance" and igniting the debate on whether dinosaurs were warm-blooded or cold-blooded. Before this, the popular conception of dinosaurs had been one of plodding, reptilian giants. Ostrom noted the small body, sleek, horizontal posture, ratite-like spine, and esp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sauropelta
''Sauropelta'' ( ; meaning 'lizard shield') is a genus of nodosaurid dinosaur that existed in the Early Cretaceous Period of North America. One species (''S. edwardsorum'') has been named although others may have existed. Anatomically, ''Sauropelta'' is one of the most well-understood nodosaurids, with fossilized remains recovered in the U.S. states of Wyoming, Montana, and possibly Utah. It is also the earliest known genus of nodosaurid; most of its remains are found in a section of the Cloverly Formation dated to 108.5 million years ago. It was a medium-sized nodosaurid, measuring about long. ''Sauropelta'' had a distinctively long tail which made up about half of its body length. Although its body was smaller than a modern black rhinoceros, ''Sauropelta'' was about the same mass, weighing in at about . The extra weight was largely due to its extensive covering of bony armor, including the characteristically large spines projecting from its neck. Description ''Sauropelta'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Cretaceous
The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Proposals for the exact age of the Barremian-Aptian boundary ranged from 126 to 117 Ma until recently (as of 2019), but based on drillholes in Svalbard the defining early Aptian Oceanic Anoxic Event 1a (OAE1a) was carbon isotope dated to 123.1±0.3 Ma, limiting the possible range for the boundary to c. 122–121 Ma. There is a possible link between this anoxic event and a series of Early Cretaceous large igneous provinces (LIP). The Ontong Java-Manihiki-Hikurangi large igneous province, emplaced in the South Pacific at c. 120 Ma, is by far the largest LIP in Earth's history. The Ontong Java Plateau today covers an area of 1,860,000 km2. In the Indian Ocean another LIP began to form at c. 120 Ma, the Kerguelen P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil Taxa Described In 1970
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 absolute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxa Named By John Ostrom
In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and given a particular ranking, especially if and when it is accepted or becomes established. It is very common, however, for taxonomists to remain at odds over what belongs to a taxon and the criteria used for inclusion. If a taxon is given a formal scientific name, its use is then governed by one of the nomenclature codes specifying which scientific name is correct for a particular grouping. Initial attempts at classifying and ordering organisms (plants and animals) were set forth in Carl Linnaeus's system in ''Systema Naturae'', 10th edition (1758), as well as an unpublished work by Bernard and Antoine Laurent de Jussieu. The idea of a unit-based system of biological classification was first made widely available in 1805 in the intro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
