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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 model.

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.

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Dann Pigdon
GIS / Archaeologist              http://geo_cities.com/dannsdinosaurs
Melbourne, Australia             http://heretichides.soffiles.com
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