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Re: [dinosaur] Feduccia on bird evolution + genetics of flight origins + morphological phylogenetics (free pdfs)
> Feduccia A 2016 Fantasy vs reality: a critique of Smith et al.'s bird
> origins. Open Ornithol J 9: 14–38
The title is perversely ironic. In his latest salvo, Feduccia
re-hashes the same boilerplate that pervades his previous literary
forays. All his bugbears can be readily refuted (and already have
been, time and time again.).
* A theropod origin of birds does *not* automatically mean a
terrestrial/cursorial origin of flight. (I mean... really?)
* A 'tetrapteryx' morphology (= having 'wings' on the forelimbs and
hindlimbs) does *not* automatically mean that the animal was a
four-winged glider. In fact, it's not clear what the 'hindwings' were
actually for in these 'tetrapteryx' theropods. The function may
have differed among different taxa (_Microraptor_ may have used its
hindwings for a function different to _Sapeornis_, and so on.)
* Basal birds like _Archaeopteryx_ and _Confucisuornis_, and their
non-avialan cousins like _Microraptor_, had osteologies consistent
with being terrestrial bipeds, not arboreal quadrupeds. (This does not
rule out the possibility of occasional tree-climbing by these taxa...
but this is a long way from being truly arboreal.)
* Elongate hindlimb feathers would be no more a hindrance to
terrestrial locomotion than to arboreal locomotion (clambering
around among the branches of a tree crown).
* Flight in birds could have arisen in a terrestrial/cursorial biped.
All that is required is for the wings (on the forelimbs) to be able to
generate enough lift to launch from the ground, with the hindlimbs
providing the impulse. As long as this terrestrial route to flight is
biophysically and biomechanically possible, then it cannot be refuted
by arboreal/'gravity-assisted' scenarios that are energetically
'cheaper'. Evolution can only act on what is available; it isn't
deterred by alternatives that are (allegedly) 'easier' or intuitively