Saturday, October 27, 2012

Previously described feathered dinosaurs reveal a fascinating record of feather evolution, although substantial phylogenetic gaps remain. Here we report the occurrence of feathers in ornithomimosaurs, a clade of non-maniraptoran theropods for which fossilized feathers were previously unknown. The Ornithomimus specimens, recovered from Upper Cretaceous deposits of Alberta, Canada, provide new insights into dinosaur plumage and the origin of the avian wing. Individuals from different growth stages reveal the presence of a filamentous feather covering throughout life and winglike structures on the forelimbs of adults. The appearance of winglike structures in older animals indicates that they may have evolved in association with reproductive behaviors. These specimens show that primordial wings originated earlier than previously thought, among non-maniraptoran theropods."
Ornithomimosaurs have been considered as secondarily flightless birds.  
"Gregory S. Paul has proposed that Ornithomimosauria might be a group of primitive, flightless birds, more advanced than Deinonychosauria and Oviraptorosauria.[9]"
"Flightless birds are birds which lack the ability to fly, relying instead on their ability to run or swim. They evolved from flying ancestors.[1] There are about forty species in existence today,[2] the best known being the ostrichemu,cassowaryrheakiwi, and penguin."
Because ornithomimosaurs are treated as being members of the Maniraptoriformes they are expected by many to have had feathers like many other dinosaurs that belong to this group have been confirmed to have had.‭ ‬Unfortunately there is currently no firm evidence to confirm this for ornithomimosaurs,‭ ‬and the impression that confirms a gular‭ (‬throat‭) ‬pouch in Pelecanimimus does not show the presence of feathers.‭

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