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... Science Frontiers ONLINE No. 78: Nov-Dec 1991 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Fossil Identity Still Up In The Air In 1986, we reported the discovery of bird-like fossils in Texas by S. Chatterjee, a paleontologist at Texas Technical University. Chatterjee was so certain that the fossils (two specimens exist) were primitive birds that he named the species Protoavis texensis (first bird from Texas). During the past five years, the scientific community has chafed while Chatterjee studied his finds and wrote them up. It seems that many paleontologists do not think that Proto-avis is really a bird at all, and Chatter jee has been slow in releasing details. But now his first paper has appeared in the Philosophical Transactions of the Royal Society . Result: Many doubts still remain about the status of Protoavis. A. Feduccia: "Calling this the original bird is irresponsible." (1 ) J.H . Ostrom: "Sad to say, for all its length, little support for the claim is to be found in this paper." (2 ) J. Gauthier: While some of the bones appear bird-like, they also look dinosaurian and could represent a new type of theropod dinosaur. (3 ) For his part, Chjatterjee asserts that Protoavis' skull has 23 features that are fundamentally bird-like, as are the forelimbs, the shoulders, and the hip girdle. "His reconstruction also shows a flexible neck, large brain, binocular vision, and, ...
Terms matched: 1 - Score: 79 - 15 May 2017 - URL: /sf078/sf078b06.htm
... Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Archaeopteryx a dead end?" Just as the 150-million-year-old Archaeopteryx fossil is being reinstated as the earliest known bird after considerable controversy, along come two crowsize skeletons that are not only 75 million years older than Archaeopteryx but also more birdlike, according to the paleontologists who discovered them. The Washington, D.C .- based National Geographic Society, which funded the work, announced this week that Sankar Chatterjee and his colleagues at Texas Tech University in Lubbock found the 225-million-year-old fossils near Post, Tex." (Weisburd, S.; "Oldest Bird and Longest Dinosaur," Science News, 130:103, 1986.) Chatterjee has named the new fossil Protoavis. "Protoavis seems certain to reopen the long-running controversy on the evolution of birds. In particular whether the common ancestor of birds and dinosaurs was itself a dinosaur. Protoavis, from the late Triassic, appears at the time of the earliest dinosaurs, and if the identification is upheld it seems likely that it will be used to argue against the view of John Ostrom of Yale University that birds are descended from the dinosaurs. It also tends to confirm what many paleontologists have long suspected, that Archaeopteryx is not on the direct line to modern birds. It is in some ways more reptilian than Protoavis, and the period between the late Jurassic Archaeopteryx and the world-wide radiation of birds in the Cretaceous has to some seemed suspiciously brief." (Anonymous; "Fossil Bird ...
Terms matched: 1 - Score: 67 - 15 May 2017 - URL: /sf048/sf048p11.htm
... Avian Graveyards BBB42 Huddling and Stacking BBB43 Bird Battles BBB44 Miscellaneous Curiosities of Avian Behavior BBC CHEMICAL PHENOMENA BBC1 Palatable Eggs More Vulnerable to Predation BBC2 Conspicuous Plumage Advertises Unpalatability BBC3 Why Did Stinking Birds Evolve? BBC4 Poisonous Birds and Poison Dart Frogs: Convergent Evolution? BBC5 Are Ratites More Primitive Than Flying Birds? BBC6 Did Australian Songbirds Evolve Earlier than European Songbirds? BBC7 Are Birds More Closely Related to Mammals Than to Reptiles? BBC8 The Inability of Some Birds to Synthesize Ascorbic Acid BBD DISTRIBUTION OF BIRDS IN SPACE AND TIME BBD1 Discontinuous Populations of Birds BBD2 Uncolonized Areas: Unfilled Niches BBD3 Land Birds Observed Far at Sea BBD4 Late Survival of Moas and Passenger Pigeons BBD5 Distribution Curiosities BBE THE FOSSIL RECORD OF BIRDS BBE1 The Fossil Record of Birds and Associated Paradigms BBE2 Evidence against the Dinosaur Origin of Birds BBE3 Protoavis: A Pre-Archaeopteryx Bird? BBE4 Unresolved Nature of Archaeopteryx BBE5 The Apparent Absence of Transitional Forms of Feathers BBE6 Fossils of Ostrich Ancestors in the Northern Hemisphere BBE7 Controversial Feathers of the London Archaeopteryx Fossil BBE8 Giant Fossil Eggs BBF BODILY FUNCTIONS BBF1 The Avian Respiratory System: Unique, Complex, Sophisticated BBF2 Avian Bodily Functions: Some Oddities BBG GENETICS BBG1 Species mtDNA More Diverse Than Morphology BBG2 Discordance in the Date of Divergence of Modern Birds BBG3 Discordances between Phylogenies Established from Morphology and DNA Analysis BBG4 Dearth of Introns in Birds BBI INTERNAL STRUCTURES AND SYSTEMS BBI1 Avian Magnetoreceptors: Hard to Find BBI2 Curious Internal Structures BBO ORGANS BBO1 Complexity and Sophistication of Some Owl Ear-Brain, Sound-Localization Systems BBO2 Regeneration of Brain Neurons BBO3 Curiosities of Avian Brains BBO4 The Pecten: A Unique Structure in ...
Terms matched: 1 - Score: 6 - 15 May 2017 - URL: /cat-biol.htm
