Protobird is an informal term that has been used by some paleontologist s when discussing animals that, while technically classified as non avian dinosaur s, possess many features normally associated with bird s. All protobirds are extinct . Zhou and Farlow 2001 , for example, used the term protobird for primitive members of the clade Avialae . In this sense, protobirds would include animals like Confuciusornis , Sapeornis , and the Enantiornithes . These animals were small, flying, feathered, and closely related to birds. The authors restricted the term bird to refer only to Aves , which they used to mean only modern crown group birds. ref Zhou, Z. and Farlow, J.O. 2001 . Flight Capability and habits of Confuciusornis. Pp. 237 245 in New Perspectives on the Origin and Early Evolution of Birds . Peabody Museum of Natural History, Yale University, New Haven, USA. ref Gregory S. Paul used the term protobird in a wider sense in 1988, to refer to the extremely bird like non avian dinosaurs Maniraptora , including Oviraptorosauria oviraptorosaurs , Troodontidae troodontids , and Dromaeosauridae dromaeosaurids . ref name paul1988 Paul, Gregory S. 1988 . Predatory Dinosaurs of the World. New York Simon and Schuster. 464 pp. ref Paul speculated that these forms were so bird like they probably had feather s, an idea later proven by fossil evidence. See also Feathered dinosaurs References reflist dinosaur stub Category Dinosaurs Category Extinct birds ... more details
Automatic taxobox image Longisquama BW.jpg image width 200px image caption One interpretation of Longisquama insignis fossil range Middle Triassic Middle or Late Triassic display parents 2 authority Sharov, 1970 type species extinct L. insignis type species authority Sharov, 1970 Longisquama is an extinct genus of lizard like reptile . There is only one species, Longisquama insignis , known from a poorly preserved skeleton and several incomplete fossil impressions from the Middle Triassic Middle to Late Triassic Madygen Formation in Kyrgyzstan . It is known from a type fossil specimen slab and counterslab PIN 2548 4 and PIN 2584 5 , and five referred specimens of possible integumentary appendages PIN 2584 7 through 9 . All specimens are in the collection of the Paleontological Institute of the Russian Academy of Sciences in Moscow . Longisquama means long scales the specific name zoology specific name insignis refers to its small size. The Longisquama holotype is notable for a number of long structures that appear to grow from its skin. These structures have been interpreted as either primitive feathers suggesting Longisquama is a close relative of birds, or as feather like structures that have evolved independently and do not indicate a close relationship with birds. Longisquama has been used in a heavily publicized debate on of the origin of bird s. To some, Longisquama is the gliding, cold blooded, protobird predicted by Gerhard Heilmann s hypothetical Proavis in 1927, and it proves that birds are not dinosaurs. To others, it is an ambiguous diapsid and has no bearing on the origin of birds. Description Integumentary structures Image Longisquama insignis skeleton&silhouette small.jpg thumb left Skeletal reconstructions of Longisquama . All specimens of Longisquama have feather like structures projecting from the back. The holotype PIN 2584 4 is the only specimen preserving these appendages with an associated skeleton. It has 7 appendages radiating in a fan like p ... more details
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