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Nanosaurus
''Nanosaurus'' ("small or dwarf lizard") is the name given to a genus of neornithischian dinosaur that lived about 155 to 148 million years ago, during the Late Jurassic-age. Its fossils are known from the Morrison Formation of the south-western United States. The type and only species, ''Nanosaurus agilis'', was described and named by Othniel Charles Marsh in 1877. The taxon has a complicated taxonomic history, largely the work of Marsh and Peter M. Galton, involving the genera ''Laosaurus'', ''Hallopus'', ''Drinker'', ''Othnielia'', and ''Othnielosaurus'', the latter three now being considered to be synonyms of ''Nanosaurus''. It had historically been classified as a hypsilophodont or fabrosaur, types of generalized small bipedal herbivore, but more recent research has abandoned these groupings as paraphyletic and ''Nanosaurus'' is today considered a basal member of Neornithischia. Description ''Nanosaurus'' is known from material from all parts of the body, including tw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanosaurus
''Nanosaurus'' ("small or dwarf lizard") is the name given to a genus of neornithischian dinosaur that lived about 155 to 148 million years ago, during the Late Jurassic-age. Its fossils are known from the Morrison Formation of the south-western United States. The type and only species, ''Nanosaurus agilis'', was described and named by Othniel Charles Marsh in 1877. The taxon has a complicated taxonomic history, largely the work of Marsh and Peter M. Galton, involving the genera ''Laosaurus'', ''Hallopus'', ''Drinker'', ''Othnielia'', and ''Othnielosaurus'', the latter three now being considered to be synonyms of ''Nanosaurus''. It had historically been classified as a hypsilophodont or fabrosaur, types of generalized small bipedal herbivore, but more recent research has abandoned these groupings as paraphyletic and ''Nanosaurus'' is today considered a basal member of Neornithischia. Description ''Nanosaurus'' is known from material from all parts of the body, including tw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Othnielosaurus Size Comparison By PaleoGeek
''Nanosaurus'' ("small or dwarf lizard") is the name given to a genus of neornithischian dinosaur that lived about 155 to 148 million years ago, during the Late Jurassic-age. Its Fossil, fossils are known from the Morrison Formation of the south-western United States. The type species, type and only species, ''Nanosaurus agilis'', was Species description, described and named by Othniel Charles Marsh in 1877. The taxon has a complicated taxonomic history, largely the work of Marsh and Peter M. Galton, involving the genera ''Laosaurus'', ''Hallopus'', ''Drinker'', ''Othnielia'', and ''Othnielosaurus'', the latter three now being considered to be synonyms of ''Nanosaurus''. It had historically been classified as a hypsilophodont or Fabrosauridae, fabrosaur, types of generalized small bipedal herbivore, but more recent research has abandoned these groupings as paraphyletic and ''Nanosaurus'' is today considered a Basal (phylogenetics), basal member of Neornithischia. Description '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laosaurus
''Laosaurus'' (meaning "stone or fossil lizard") is a genus of neornithischian dinosaur. The type species, ''Laosaurus celer'', was first described by O.C. Marsh in 1878 from remains from the Oxfordian-Tithonian-age Upper Jurassic Morrison Formation of Wyoming. The validity of this genus is doubtful because it is based on fragmentary fossils. A second species from the Morrison Formation, ''L. gracilis'', and a species from the late Cretaceous Allison Formation of Alberta, Canada, ''Laosaurus minimus'', are also considered dubious. History and taxonomy Marsh (1878a) named his new genus from vertebrae ( YPM 1874) found by Samuel Wendell Williston at Como Bluff, Wyoming, from rocks of the Morrison Formation. The type material includes nine partial and two complete tail vertebral centra, which he concluded came from a "fox-sized" animal. In the same year, he named two other species: ''L. gracilis'', originally based on a back vertebral centrum, a tail vertebral centrum, and p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hallopus
''Hallopus'' was a prehistoric reptile, named in 1877 as a species of ''Nanosaurus'' and classified by Othniel Charles Marsh, O. C. Marsh in 1881 from the Late Jurassic Morrison Formation. Today though the animal is thought to be a pseudosuchian more closely related to crocodilians. It was redescribed as a sphenosuchian Crocodylomorpha, crocodylomorph in 1970, now thought to be a paraphyletic group. It was a quite small animal, reaching a length of 1 m (3.3 ft) with long and slender limbs. ''Macelognathus'', a similarilly slender-proportioned crocodylomorph to ''Hallopus'', may be synonymous with it. History and naming The holotype specimen of ''Hallopus'' was discovered by near Canyon City, Colorado and acquired by a collector named Baldwin for three dollars in a local curiosity shop in Colorado Springs. According to letters later chronicled by Schuchert (1939), he found out about the fossil after hearing about the discovery of a supposed fossil bird, before later trav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Othniel Charles Marsh
Othniel Charles Marsh (October 29, 1831 – March 18, 1899) was an American professor of Paleontology in Yale College and President of the National Academy of Sciences. He was one of the preeminent scientists in the field of paleontology. Among his legacies are the discovery or description of dozens of new species and theories on the origins of birds. Born into a modest family, Marsh was able to afford higher education thanks to the generosity of his wealthy uncle George Peabody. After graduating from Yale College in 1860 he travelled the world, studying anatomy, mineralogy and geology. He obtained a teaching position at Yale upon his return. From the 1870s to 1890s, he competed with rival paleontologist Edward Drinker Cope in a period of frenzied Western American expeditions known as the Bone Wars. Marsh's greatest legacy is the collection of Mesozoic reptiles, Cretaceous birds, and Mesozoic and Tertiary mammals that now constitute the backbone of the collections of Yale's Peabo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypsilophodont
Hypsilophodontidae (or Hypsilophodontia) is a traditionally used family of ornithopod dinosaurs, generally considered invalid today. It historically included many small bodied bipedal neornithischian taxa from around the world, and spanning from the Middle Jurassic until the Late Cretaceous. This inclusive status was supported by some phylogenetic analyses from the 1990s and mid 2000s, although there have also been many finding that the family is an unnatural grouping which should only include the type genus, ''Hypsilophodon'', with the other genera being within clades like Thescelosauridae and Elasmaria. A 2014 analysis by Norman recovered a grouping of ''Hypsilophodon'', Rhabdodontidae and ''Tenontosaurus'', which he referred to as Hypsilophodontia. All other analyses from around the same time have instead found these latter taxa to be within Iguanodontia. Linnaean usage Hypsilophodontidae was named originally in 1882 by Louis Dollo, as a family to include ''Hypsilophodon'' a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neornithischian
Neornithischia ("new ornithischians") is a clade of the dinosaur order Ornithischia. It is the sister group of the Thyreophora within the clade Genasauria. Neornithischians are united by having a thicker layer of asymmetrical enamel on the inside of their lower teeth. The teeth wore unevenly with chewing and developed sharp ridges that allowed neornithischians to break down tougher plant food than other dinosaurs. Neornithischians include a variety of basal forms historically known as "hypsilophodonts", including the Parksosauridae; in addition, there are derived forms classified in the groups Marginocephalia and Ornithopoda. The former includes clades Pachycephalosauria and Ceratopsia, while the latter typically includes ''Hypsilophodon'' and the more derived Iguanodontia. Classification Neornithischia was first named by Cooper in 1985 and defined as "all genasaurians more closely related to '' Parasaurolophus walkeri'' than to ''Ankylosaurus magniventris'' or ''Stegosaurus st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Talenkauen
''Talenkauen'' is a genus of basal iguanodont dinosaur from the Campanian or Maastrichtian age of the Late Cretaceous Cerro Fortaleza Formation, formerly known as the Pari Aike Formation of Patagonian Lake Viedma, in the Austral Basin of Santa Cruz, Argentina. It is based on MPM-10001A, a partial articulated skeleton missing the rear part of the skull, the tail, and the hands. The type and only species is ''Talenkauen santacrucensis''. Discovery and naming One among a string of discoveries of ornithopods in South America, following taxa such as ''Gasparinisaura'' and ''Anabisetia'', the specimen that would become ''Talenkauen'' was collected in February 2000 and would later be described and named in a short 2004 paper by Fernando E. Novas and colleagues. It was discovered on Los Hornos Hill on the coast of Viedma Lake, in the Santa Cruz Province region of Argentina. Geologically, it hails from the Cerro Fortaleza Formation. The holotype specimen is MPM–10001A, a relati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypsilophodon
''Hypsilophodon'' (; meaning "''Hypsilophus''-tooth") is a neornithischian dinosaur genus from the Early Cretaceous period of England. It has traditionally been considered an early member of the group Ornithopoda, but recent research has put this into question. The first remains of ''Hypsilophodon'' were found in 1849; the type species, ''Hypsilophodon foxii'', was named in 1869. Abundant fossil discoveries were made on the Isle of Wight, giving a good impression of the build of the species. It was a small, agile bipedal animal with an herbivorous or possibly omnivorous diet, measuring long and weighing . It had a pointed head equipped with a sharp beak used to bite off plant material, much like modern day parrots. Older studies have given rise to a number of misconceptions about ''Hypsilophodon'' that it was an armored, arboreal animal and that it could be found in areas outside of Wight. During the past decades, new researches have gradually shown this to be incorrect. Discov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1877 In Paleontology
Arthropods Newly named insects Fish Non-dinosaurian reptiles Dinosaurs ''Laelaps trihedrodon'', Cope criticizes ''Dryptosaurus'' O. W. Lucas collected the first remains of what would later in the year be named ''Laelaps trihedrodon'' from Quarry I of the Saurian Hill at Garden Park, Colorado."Introduction," Chure (2001) page 11. Edward Drinker Cope would describe the material later in the year in a short paper titled "On a carnivorous dinosaurian from the Dakota beds of Colorado."Cope (1887) pages 805-806. The "Dakota beds" he references are actually Morrison Formation strata. Cope claims to have a skeleton of unspecified completeness on which to establish the new species, but only describes a partial dentary which has 5 successional teeth, 2 functional teeth, and one tooth missing from its socket. All of the preceding material has since been lost to science with the exception of 5 broken, partial tooth crowns."Description of 5780," Chure (2001) page 11. From the now missi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus comes above species and below family (taxonomy), family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. ''Panthera leo'' (lion) and ''Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomy (biology), taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basal (phylogenetics)
In phylogenetics, basal is the direction of the ''base'' (or root) of a phylogenetic tree#Rooted tree, rooted phylogenetic tree or cladogram. The term may be more strictly applied only to nodes adjacent to the root, or more loosely applied to nodes regarded as being close to the root. Note that extant taxa that lie on branches connecting directly to the root are not more closely related to the root than any other extant taxa. While there must always be two or more equally "basal" clades sprouting from the root of every cladogram, those clades may differ widely in taxonomic rank, Phylogenetic diversity, species diversity, or both. If ''C'' is a basal clade within ''D'' that has the lowest rank of all basal clades within ''D'', ''C'' may be described as ''the'' basal taxon of that rank within ''D''. The concept of a 'key innovation' implies some degree of correlation between evolutionary innovation and cladogenesis, diversification. However, such a correlation does not make a given ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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