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5 global distribution of derived theropods

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Unformatted text preview: s Therizinosaurs Troodontids Dromaeosaurs ? TAKE A BREAK! 14 Beipiasaurus 5/24/2013 Based on cladistic analysis, relative age (as known from the geologic record) FeathersFeathers Are they just for the birds? 15 5/24/2013 Feather structure Vane Rachis (shaft) Barb Down feathers Calamus (quill) Pennaceous (vaned) feathers Flight feathers (asymmetric) Plumaceous disorganized) feathers Flight feathers = asymmetrical 16 5/24/2013 The most complex skin coverings found in vertebrates (past or present) VARIETIES Filoplumes Flight feathers (vaned, asymmetrical) Contour feathers (vaned, symmetrical) remiges Down rectrices Why Feathers? They provide lift Why Feathers? They provide insulation (help with thermoregulation) 17 5/24/2013 Why Feathers? They make you pretty, and distinctive Liaoning Feathered Dinosaurs Sinornithosaurus Protarchaeopteryx Liaoxiornis These animals were not were not fliers! fliers! Caudipteryx Sinosauropteryx Sinosauropteryx Early Cretaceous Proposed feather evolution based on fossils from Early Cretaceous rocks in Liaoning Province , China not the result of the scale evolution Conclusion: Conclusion: feathers did not originally evolve to allow flight 18 5/24/2013 It all started with Sinosauropteryx… Sinosauropteryx… Disc. 1996 http://www.youtube.com/watch?v=LQcoLWJmsp0 Microraptor + Caudipteryx 19 5/24/2013 Caudipteryx Microraptor Beipiasaurus Broad feathers 20 5/24/2013 Sinornithosaurus A Deinonychus-like dromaeosaurid? Epidexipteryx (classification uncertain) Late Jurassic? Inferred feathers…. Velciraptor Quill knobs! 21 5/24/2013 THE PUZZLE: true birds with asymmetric, vaned feathers were around in the Late Jurassic ? Turner et al., 2007, A Basal Dromaeosaurid and Size Evolution Preceding Avian Flight, Science, v. 317. The Million Dollar Question: What was the original function of feathers? The End! 22...
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