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Re: Dinosaur Revolution Review

Am 16.09.2011 03:40, schrieb Jura:

While the lack of scale plasticity in extant birds may very well be a derived trait, I 
still can't help but wonder about the old "party line" regarding why scales 
were lost in the first place (i.e. the weight reduction hypothesis).

~:-| This is the first time I encounter that hypothesis at all. Weight reduction? Scales? Seriously?

The scales angle would be hard, but one could try at least test the other trait 
that is often argued to have been lost do to weight reduction (teeth). In that 
case it would just require gluing teeth to the bills of some flapping birds and 
then looking at the change in flight costs associated with it.

Yep. Someone should probably do that.

I once held a sheep skull (without the lower jaws) and was astonished at how heavy the teeth were. The center of mass was outside the skull, between the molars and below the (secondary) palate. But sheep molars are much, much bigger than any teeth any bird ever had... and there are pterosaurs with very long, robust-looking teeth just as well as toothless ones.

Going back from feathers to scales would be more difficult and might have 
"required" a naked skin stage, but judging from what we currently know about 
scale formation in birds, it too could have occurred as a coup
ion on the cascade that lead to integument development on the tarsometatarsus.

As usual, the last paragraph of your messages gets attacked by the snip demon.