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re: Coelurosauravus: glider? or bluffer?



Maybe this mental picture will help:

You can pick up a pterosaur, a bird, a bat or Draco or Icarosaurus by its wing 
tips and youâ??ll pick up the whole animal.

Coelurosauravus is like a lizard with toothpicks glued to its lateral torso 
skin. Pick up the tips of the â??tooth picksâ?? and they bend up creating a 
dihedral angle. How large? Thatâ??s the question. Too large and it hurts and it 
doesnâ??t fly. Not too large and it flies. I guess it comes down to a judgement 
call: at the root of the spar is the connection strong enough or broad enough? 

The wing spars of birds, bats and Draco are surrounded by and supported by 
muscles, tendons, and ligaments. In Icarosaurus and Coelurosauravus, youâ??ve 
only got skin and the same minor dermal muscles that cause feathers and quills 
to erect. And thereâ??s no anchor deeper than the dermis in Coelurosauravus. 
That means thereâ??s no muscular or mechanical leverage acting upon the spars 
from inside the body to support them.

Come to think of it, I canâ??t think of any other â??reptileâ?? able to erect a 
dermal appendage independent of its skeleton.

Back to Timâ??s point about rhino horns and porcupine quills. Neither supports 
the entire body in flight. Rhin horns do have a broad base - exactly the sort 
of broad base found in kuehneosaurids. Thatâ??s all Iâ??m looking for here. 
Porcupine quills donâ??t have a broad base. Instead, I believe, they are shed.

Final point: 
Birds, bats, and pterosaurs throughout their phylogeny use pretty much the same 
engineering in their wings as the first birds, bats and pterosaurs. Sure some 
parts are bigger and shorter, but the parts are all glued together the same 
way. If Coelurosauravus was a good glider, why do we see improvements at the 
spar bases in Kuehneosaurids, right where the hypothetical weaknesses have been 
located in their purported ancestors?

Here again, it looks like display was co-opted for flight.

dp
stl