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Sankar Chatterjee
Sankar Chatterjee (born May 28, 1943) is a paleontologist, and is the Paul W. Horn Professor of Geosciences at Texas Tech University and Curator of Paleontology at the Museum of Texas Tech University. He earned his Ph. D. from the University of Calcutta in 1970 and was a Post-doctoral Fellow at the Smithsonian Institution from 1977-1978. Chatterjee has focused on the origin, evolution, functional anatomy, and systematics of Mesozoic vertebrates, including basal archosaurs, dinosaurs, pterosaurs, and birds. He has researched Late Triassic reptiles in India, such as phytosaurs, rhynchosaurs, and prolacertiformes. He is best known for his work on vertebrates recovered in the 1980s from the Post Quarry in the Late Triassic Cooper Canyon Formation (Dockum Group) of West Texas. The material includes the large rauisuchian '' Postosuchus'', which was named for the nearby town of Post. It also included controversial specimens Chatterjee identified as being avian ('' Protoavis''). The i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kolkata
Kolkata (, or , ; also known as Calcutta , the official name until 2001) is the capital of the Indian state of West Bengal, on the eastern bank of the Hooghly River west of the border with Bangladesh. It is the primary business, commercial, and financial hub of Eastern India and the main port of communication for North-East India. According to the 2011 Indian census, Kolkata is the seventh-most populous city in India, with a population of 45 lakh (4.5 million) residents within the city limits, and a population of over 1.41 crore (14.1 million) residents in the Kolkata Metropolitan Area. It is the third-most populous metropolitan area in India. In 2021, the Kolkata metropolitan area crossed 1.5 crore (15 million) registered voters. The Port of Kolkata is India's oldest operating port and its sole major riverine port. Kolkata is regarded as the cultural capital of India. Kolkata is the second largest Bengali-speaking city after Dhaka ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhynchosaur
Rhynchosaurs are a group of extinct herbivorous Triassic archosauromorph reptiles, belonging to the order Rhynchosauria. Members of the group are distinguished by their triangular skulls and elongated, beak like premaxillary bones. Rhynchosaurs first appeared in the Middle Triassic or possibly the Early Triassic, before becoming abundant and globally distributed during the Carnian stage of the Late Triassic. Description Rhynchosaurs were herbivores, and at times abundant (in some fossil localities accounting for 40 to 60% of specimens found), with stocky bodies and a powerful beak. Early primitive forms, like ''Mesosuchus'' and ''Howesia'', were generally small and more typically lizard-like in build, and had skulls rather similar to the early diapsid '' Youngina'', except for the beak and a few other features. Later and more advanced genera grew to medium to medium large size, up to two meters in length. The skull in these forms were short, broad, and triangular, becoming mu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1994 In Paleontology
Plants Conifers Angiosperms Arthropods Insects Molluscs Bivalves Fishes Newly named bony fishes Archosauromorphs * Aff. Rebbachisaurus gastroliths documented.Calvo (1994). Sanders, Manley, and Carpenter (2001), "Table 12.1" page 167. * The "Talkeetna Mountains Hadrosaur" specimen was discovered in a quarry being excavated for road material. The quarry is near the Glenn Highway, approximately 150 miles northeast of Anchorage. That fall, excavation began, and was resumed in the summer of 1996. Newly named pseudosuchians Newly named basal dinosauromorphs Newly named dinosaurs Data courtesy of George Olshevsky's dinosaur genera list. Birds Plesiosaurs * Plesiosaur gastroliths documented.Martin (1994). Sanders, Manley, and Carpenter (2001), "Table 12.1" page 167. New taxa Pterosaurs New taxa Other diapsids New taxa Footnotes {{Reflist, , refs= "Introduction," in Pasche and May (2001); page 220. "Location and Geologic Setting," in Pasche and May (2001) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alwalkeria
''Alwalkeria'' (; "for Alick Walker") is a genus partly based on basal saurischian dinosaur remains from the Late Triassic, living in India. A thighbone found indicates a small bipedal form. It has been seen as a chimera. Etymology This taxon was originally named ''Walkeria maleriensis'' by Sankar Chatterjee in 1987, in honor of British paleontologist Alick Walker. However, since the original generic name was found to be preoccupied by a bryozoan, the name ''Alwalkeria'' was created in 1994 by Chatterjee and Ben Creisler. The specific name ''maleriensis'' is a reference to the Maleri Formation, in southern India, where its fossils were found. Description The only known specimen, holotype ISI R306 is incomplete and consists of parts of the front ends of the upper and lower jaws, 28 incomplete vertebrae from all parts of the spinal column, most of a femur, and an astragalus (ankle bone). The partial skull is about 4 centimeters long (1.5 in). Although material of ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tupandactylus
''Tupandactylus'' (meaning "Tupan finger", in reference to the Tupi thunder god) is a genus of tapejarid pterodactyloid pterosaur from the Early Cretaceous Crato Formation of Brazil. History ''Tupandactylus imperator'' is known from four nearly complete skulls. The holotype specimen is MCT 1622-R, a skull and partial lower jaw, found in the Crato Formation, dating to the boundary of the Aptian-Albian stages of the early Cretaceous period, about 112 Ma ago.Martill, D.M., Bechly, G. and Loveridge, R.F. (2007). ''The Crato fossil beds of Brazil: window into an ancient world.'' Cambridge University Press. , It was initially described as a species of '' Tapejara'', but later research has indicated it warrants its own genus. The skull was toothless and had a prominent sagittal crest, only the base of which was bony: the front of the crest featured a tall bony rod extending up and back, and the rear of the crest had a long prong of bone projecting behind it. The bulk of the crest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crest (feathers)
The crest is a prominent feature exhibited by several bird and other dinosaur species on their heads. It is distinct from features such as casques and cockscombs - sometimes erroneously referred to as "crests", which are bony and fleshy structures respectively. The crest is made up of semiplume feathers: a long rachis with barbs on either side. These are plumulaceous feathers, meaning that they are soft and bendable. In birds, these semiplumes are common along the head, neck, and upper back, and may be used for buoyancy and sensing vibrations. Crests on birds are generally used for display purposes. Cockatoos and their smaller cousins, cockatiels, are part of the parrot family Cacatuidae found in Australia, the Bismarck Archipelago and the Philippines, and are probably the most recognizable birds to feature crests. Cockatoos and cockatiels possess crests which may be raised or lowered at will. Their crests are used to communicate with fellow members of their species, or as a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rudder
A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other vehicle that moves through a fluid medium (generally air or water). On an aircraft the rudder is used primarily to counter adverse yaw and p-factor and is not the primary control used to turn the airplane. A rudder operates by redirecting the fluid past the hull or fuselage, thus imparting a turning or yawing motion to the craft. In basic form, a rudder is a flat plane or sheet of material attached with hinges to the craft's stern, tail, or after end. Often rudders are shaped so as to minimize hydrodynamic or aerodynamic drag. On simple watercraft, a tiller—essentially, a stick or pole acting as a lever arm—may be attached to the top of the rudder to allow it to be turned by a helmsman. In larger vessels, cables, pushrods, or hydraulics may be used to link rudders to steering wheels. In typical aircraft, the rudder is operated by pedals via mechanical li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unmanned Aerial Vehicle
An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controller and a system of communications with the UAV. The flight of UAVs may operate under remote control by a human operator, as remotely-piloted aircraft (RPA), or with various degrees of autonomy, such as autopilot assistance, up to fully autonomous aircraft that have no provision for human intervention. UAVs were originally developed through the twentieth century for military missions too "dull, dirty or dangerous" for humans, and by the twenty-first, they had become essential assets to most militaries. As control technologies improved and costs fell, their use expanded to many non-military applications.Hu, J.; Bhowmick, P.; Jang, I.; Arvin, F.; Lanzon, A.,A Decentralized Cluster Formation Containment Framework for Multirobot Systems IEEE ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protoavis
''Protoavis'' (meaning "first bird") is a problematic taxon known from fragmentary remains from Late Triassic Norian stage deposits near Post, Texas. Much controversy remains over the animal, and there are many different interpretations of what ''Protoavis'' actually is. When it was first described, the fossils were described as being from a primitive bird which, if the identification is valid, would push back avian origins some 60-75 million years. The original describer of ''Protoavis texensis'', Sankar Chatterjee of Texas Tech University, interpreted the type specimen to have come from a single animal, specifically a 35 cm tall bird that lived in what is now Texas, USA, around 210 million years ago. Though it existed far earlier than ''Archaeopteryx'', its skeletal structure is more bird-like. ''Protoavis'' has been reconstructed as a carnivorous bird that had teeth on the tip of its jaws and eyes located at the front of the skull, suggesting a nocturnal or crepuscular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Post, Texas
Post is a city in and the county seat of Garza County, Texas, United States. Its population was 5,376 at the 2010 census. History Post is located on the edge of the caprock escarpment of the Llano Estacado, the southeastern edge of the Great Plains. It is at the crossroads of U.S. Routes 84 and 380. The land belonged to John Bunyan Slaughter, as it was on his U Lazy S Ranch. In 1906, Slaughter sold it to Charles William (C. W.) Post -->, the manufacturer, who founded "Post City" as a colonizing venture in 1907. Post devised the community as a model town. He purchased of ranchland and established the Double U Company to mana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Postosuchus
''Postosuchus'', meaning "Crocodile from Post", is an extinct genus of rauisuchid reptiles comprising two species, ''P. kirkpatricki'' and ''P. alisonae'', that lived in what is now North America during the Late Triassic. ''Postosuchus'' is a member of the clade Pseudosuchia, the lineage of archosaurs that includes modern crocodilians (the other main group of archosaurs is Avemetatarsalia, the lineage that includes non-avian dinosaurs and their descendants, birds). Its name refers to Post Quarry, a place in Texas where many fossils of the type species, ''P. kirkpatricki'', were found. It was one of the apex predators of its area during the Triassic, larger than the small dinosaur predators of its time (such as ''Coelophysis''). It was a hunter which probably preyed on large bulky herbivores like dicynodonts and many other creatures smaller than itself (such as early dinosaurs). The skeleton of ''Postosuchus'' is large and robust with a deep skull and a long tail. It was a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
West Texas
West Texas is a loosely defined region in the U.S. state of Texas, generally encompassing the arid and semiarid lands west of a line drawn between the cities of Wichita Falls, Abilene, and Del Rio. No consensus exists on the boundary between East Texas and West Texas. While most Texans understand these terms, no boundaries are officially recognized and any two individuals are likely to describe the boundaries of these regions differently. Walter Prescott Webb, American historian and geographer, suggested that the 98th meridian separates East and West Texas; Texas writer A.C. Greene proposed that West Texas extends west of the Brazos River. Use of a single line, though, seems to preclude the use of other separators, such as an area— Central Texas. Unlike East Texas, West Texas is not generally considered to be part of the American South, and the dry, desert climate is often more associated with the American Southwest. West Texas is often subdivided according to disti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
