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Re: 4 winged dino NOVA
Mike Habib writes:
The primary problems with the Chatterjee & Templin model stem from
feather position, which in turn seems to have (once again) derived from
an insistence on making the hind limb feathers act as weight- supporting
airfoils during steady gliding. I give C&T full points for thinking
outside the box, but here are a few of the problems with the model:
1) The feathers on the hind limb are articulated in a manner unlike
anything seen in any other taxa (including living birds). While not
impossible, this does make a broad range of assumptions about novel
feather anchoring. They need more morphological evidence to support this
That was my thought too. Flight feathers on the forelimbs have the flow of
air parallel to the central vein. In the bi-plane Microraptor model, the air
flow would be perpendicular. What would prevent the feathers from being
swept backwards and possibly breaking? Even if they bent instead of
breaking, it would still ruin the aerofoil shape of the leg 'wings'.
2) Unless the feathers could rotate, at their base, about the axis of the
long bones (tmt, primarily) then they would be in a very problematic
position for any non-gliding locomotion, including walking and running.
This type of rotating ability would be even more complicated and unusual
than the feather position itself.
Indeed. Forelimb feathers are usually anchored so as to have very little
movement. If Microraptors bi-plane leg feathers couldn't rotate, then the
animal would have to walk around with a set of broad sails impeding its
steps (I'm envisioning a dinosaurian MC Hammer, only with feathers instead
of parachute pants).
The only other option would be to twist the feet 90 degrees inward at the
ankles, which I don't think would have been anatomically possible.
GIS / Archaeologist http://geo_cities.com/dannsdinosaurs
Melbourne, Australia http://heretichides.soffiles.com