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New(ish) paper II




Charles A. Long, G. P. Zhang, Thomas F. George & Claudine F. Long. (2003) Physical theory, origin of flight, and a synthesis proposed for birds. Journal of Theoretical Biology 224: 9-26.


Contains some interesting aerodynamic discussion, though the equations made my head spin at this hour of the day. Unfortunately, the paper has a poor phylogenetic grounding; among other things, _Protoavis_ and _Longisquama_ are considered serious contenders as avian ancestors, and _Microraptor_ is called a troodontid. The authors also revert back to the old "ground-up" versus "trees-down" dichotomy. Long et al. (2003) also make some very silly statements about competing hypotheses, and they miss the point entirely concerning the WAIR hypothesis. Here are some of the wilder and stranger statements contained in the paper:

From the 'Statement of the Bleeding Obvious' File:

"Peter Mackovicky discounts the furcula as a distinctively avian feature (personal comm.)." Hmmm... aren't there one or two (or maybe thirty or forty) papers that have already established this?



From the 'Here We Go Again' File:

"_Longisquama_ possessed feather-like epidermal extensions of several kinds. These included some on the postaxial forelimbs that closely resemble flight feathers. The feathers seem homologous with bird feathers, which is perhaps not true (Alan Feduccia, pers. comm.; also see [Zhang and Zhou (2000]) of so-called feathers of the small dinosaurs (their filaments may not be derived from scales as are true feathers). The feather-like structures of _Longisquama_ suggest that birds may not be descended from the hypothesized small theropod dinosaurs after all, but from an archosaurian glider that perhaps gave rise later to some feathered forms with bipedal locomotion."



From the 'Something to Do on a Rainy Afternoon' File:

"Chickens have been observed ... thrown from the roof of a 12-story Kansas building to onlookers at a parade; the chickens flew less than 50 m horizontally but fluttered enough while falling to avoid injury." Pleased to hear it.



Finally, there's this assertion about WAIR, from the 'Splat!' File

"Were it not for what we have described as flutter-gliding, to soften impacts on landing, an accelerating vertical climb and subsequent fall would confer limited survival and evolutionary fitness." In other words, in the author's view WAIR says that pro-avians ran up vertical surfaces until they ran out of steam, then fell back down to the ground again with a (painful) thud. It's amazing that partridges haven't gone extinct. Perhaps young partridges habitually wear crash helmets.



Tim

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