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Haemal Arches
A haemal arch, also known as a chevron, is a bony arch on the ventral side of a tail vertebra of a vertebrate. The canal formed by the space between the arch and the vertebral body is the haemal canal. A spinous ventral process emerging from the haemal arch is referred to as the haemal spine. Blood vessels to and from the tail run through the arch. In reptiles, the caudofemoralis longus muscle, one of the main muscles involved in locomotion, attaches to the lateral sides of the haemal arches. In 1956, Alfred Sherwood Romer hypothesized that the position of the first haemal arch was sexually dimorphic in crocodilians and dinosaurs. However, subsequent research established that the size and position of the first haemal arch was not sexually dimorphic in crocodilians and found no evidence of significant variation in tyrannosaurid dinosaurs, indicating that haemal arches could not be used to distinguish between sexes after all. Haemal arches play an important role in the taxonomy of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nothronychus Chevrons
''Nothronychus'' (meaning "slothful claw") is a genus of therizinosaurid theropod dinosaurs that lived in North America during the Late Cretaceous period. The type species, ''Nothronychus mckinleyi'', was described by James Kirkland (paleontologist), James Kirkland and Douglas G. Wolfe in 2001 in paleontology, 2001. It was recovered near New Mexico's border with Arizona, in an area known as the Zuni Basin, from rocks assigned to the Moreno Hill Formation, dating to the Turonian stage of the Late Cretaceous. A second specimen, described in 2009 as a second species, ''Nothronychus graffami'', was found in the Tropic Shale of Utah, dating between one million and a half million years older than ''N. mckinleyi''. ''Nothronychus'' were bulky herbivorous theropods with wide, sloth-like hip (resembling that of the non-related ornithischians), four-toed feet with all four toes facing forward, elongated necks and prominent arms with sharp claws. Both species were similar in dimensions, but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebra
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 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 articulate. These foramina are the entry and exit conduits for the spinal nerves. The body of the vertebr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebrate
Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain. The vertebrates make up the subphylum Vertebrata with some 65,000 species, by far the largest ranked grouping in the phylum Chordata. The vertebrates include mammals, birds, amphibians, and various classes of fish and reptiles. The fish include the jawless Agnatha, and the jawed Gnathostomata. The jawed fish include both the Chondrichthyes, cartilaginous fish and the Osteichthyes, bony fish. Bony fish include the Sarcopterygii, lobe-finned fish, which gave rise to the tetrapods, the animals with four limbs. Despite their success, vertebrates still only make up less than five percent of all described animal species. The first vertebrates appeared in the Cambrian explosion some 518 million years ago. Jawed vertebrates evolved in the Ordovician, followed by bony fishes in the Devonian. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alfred Sherwood Romer
Alfred Sherwood Romer (December 28, 1894 – November 5, 1973) was an American paleontologist and biologist and a specialist in vertebrate evolution. Biography Alfred Romer was born in White Plains, New York, the son of Harry Houston Romer and his wife, Evalyn Sherwood. He was educated at White Plains High School. He studied at Amherst College for his Bachelor of Science Honours degree in biology, then at Columbia University for an M.Sc. in biology and a doctorate in zoology in 1921. Romer joined the department of geology and paleontology at the University of Chicago as an associate professor in 1923. He was an active researcher and teacher. His collecting program added important Paleozoic specimens to Chicago's Walker Museum of Paleontology. In 1934 he was appointed professor of biology at Harvard University. In 1946, he became director of the Harvard Museum of Comparative Zoology (MCZ). Romer was elected to the American Academy of Arts and Sciences in 1937. In 1951, he wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sauropod
Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their body), and four thick, pillar-like legs. They are notable for the enormous sizes attained by some species, and the group includes the largest animals to have ever lived on land. Well-known genera include '' Apatosaurus'', '' Argentinosaurus'', '' Alamosaurus'', ''Brachiosaurus'', '' Camarasaurus'', '' Diplodocus,'' and '' Mamenchisaurus''. The oldest known unequivocal sauropod dinosaurs are known from the Early Jurassic. '' Isanosaurus'' and '' Antetonitrus'' were originally described as Triassic sauropods, but their age, and in the case of ''Antetonitrus'' also its sauropod status, were subsequently questioned. Sauropod-like sauropodomorph tracks from the Fleming Fjord Formation (Greenland) might, however, indicate the occurrence of the g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinosaurs
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutionary history, evolution of dinosaurs is a subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 mya and their dominance continued throughout the Jurassic and Cretaceous periods. The fossil record shows that birds are feathered dinosaurs, Evolution of birds, having evolved from earlier Theropoda, 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 taxonomy (biology), taxonomic, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Othniel Marsh
Othniel Charles Marsh (October 29, 1831 – March 18, 1899) was an American professor of paleontology. A prolific fossil collector, Marsh was one of the preeminent paleontologists of the nineteenth century. Among his legacies are the discovery or description of dozens of new species—including the stegosaurus and triceratops—and theories on the origins of birds. He spent his academic career at Yale College and was president of the National Academy of Sciences. 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 traveled 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, Cretaceo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diplodocus
''Diplodocus'' (, , or ) is an extinct genus of diplodocid sauropod dinosaurs known from the Late Jurassic of North America. The first fossils of ''Diplodocus'' were discovered in 1877 by S. W. Williston. The generic name, coined by Othniel Charles Marsh in 1878, is a Neo-Latin term derived from Greek διπλός (''diplos'') "double" and δοκός (''dokos'') "beam", in reference to the double-beamed chevron bones located in the underside of the tail, which were then considered unique. The genus of dinosaurs lived in what is now mid-western North America, at the end of the Jurassic period. It is one of the more common dinosaur fossils found in the middle to upper Morrison Formation, with most specimens being found in rocks between about 151.88 and 149.1 million years ago , during the latest Kimmeridgian Age, although it may have made it into the Tithonian., with at least one specimen (AMNH FR 223) being potentially from among the youngest deposits of the formation. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wintonotitan
''Wintonotitan'' (meaning " Winton titan") is a genus of titanosauriform dinosaur from Cenomanian (Late Cretaceous)-age Winton Formation of Australia. It is known from partial postcranial remains. Description and history Fossils that are now known under the name ''Wintonotitan'' were first found in 1974 by Keith Watts. At the time, the specimens were assigned to an '' Austrosaurus'' sp., ''Austrosaurus'' then being the only named Australian Cretaceous sauropod genus. These fossils, catalogued as QMF 7292, consisted of a left shoulder blade, much of the forelimbs, a number of back, hip, and tail vertebrae, part of the right hip, ribs, chevrons, and unidentifiable fragments. QMF 7292 was established as the type specimen of ''Wintonotitan'' in 2009 by Scott Hocknull and colleagues. Hocknull suggested that ''Austrosaurus mckillopi'' differed only slightly from the QMF 7292, the holotype of ''Wintonotitan wattsii'', and should be considered a ''nomen dubium''. The type ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ichthyovenator
''Ichthyovenator'' is a genus of spinosaurid dinosaur that lived in what is now Laos, sometime between 120 and 113 million years ago, during the Aptian Stage (geology), stage of the Early Cretaceous Period (geologic time), period. It is known from fossils collected from the Grès supérieurs Formation of the Savannakhet Basin, the first of which were found in 2010, consisting of a partial skeleton without the skull or limbs. This specimen became the holotype of the new genus and species ''Ichthyovenator laosensis'', and was described by palaeontologist Ronan Allain and colleagues in 2012 in archosaur paleontology, 2012. The generic name, meaning "fish hunter", refers to its assumed piscivorous lifestyle, while the specific name alludes to the country of Laos. In 2014, it was announced that more remains from the dig site had been recovered; these fossils included teeth, more Glossary of dinosaur anatomy#vertebrae, vertebrae (backbones) and a Glossary of dinosaur anatomy#pubi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edmontosaurus
''Edmontosaurus'' ( ) (meaning "lizard from Edmonton"), with the second species often colloquially and historically known as ''Anatosaurus'' or ''Anatotitan'' (meaning "duck lizard" and "giant duck"), is a genus of hadrosaurid (duck-billed) dinosaur. It contains two known species: ''Edmontosaurus regalis'' and ''Edmontosaurus annectens''. Fossils of ''E. regalis'' have been found in rocks of western North America that date from the late Campanian Stage (stratigraphy), age of the Cretaceous Period (geology), period 73 million years ago, while those of ''E. annectens'' were found in the same geographic region from rocks dated to the end of the Maastrichtian age, 66 million years ago. ''Edmontosaurus'' was one of the last non-bird, avian dinosaurs ever to exist, and lived alongside dinosaurs like ''Triceratops'', ''Tyrannosaurus'', ''Ankylosaurus'', and ''Pachycephalosaurus'' shortly before the Cretaceous–Paleogene extinction event. ''Edmontosaurus'' included two of the lar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oksoko (dinosaur)
''Oksoko'' (''Oak-soak-oh''; from '' Öksökö'', a mythical bird of Yakut folklore) is a genus of oviraptorid dinosaur from the Late Cretaceous of Asia, that lived in what is now the Nemegt Formation in Mongolia. It includes the type species ''Oksoko avarsan''. History of discovery The first specimen of ''Oksoko'', MPC-D 100/33, was discovered in 1974 by the Soviet-Mongolian Palaeontological Expedition at the Bügiin Tsav locality in the Nemegt Formation of Mongolia. It is represented by a partial subadult postcranial skeleton. Although MPC-D 100/33 has been largely referred as a paratype of '' Heyuannia'', this specimen shares several traits with other specimens of ''Oksoko'' including a reduced third metacarpal. The holotype specimen is a block of an assemblage of three individuals buried in life positions that has been labelled as MPC-D 102/110. The first individual, subcatalogued as MPC-D 102/110a, is a partial skeleton of a juvenile preserving the skull, cervical vertebr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
