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Re: Dinosaurs and birds



Combined answer:

----- Original Message ----- From: "don ohmes" <d_ohmes@yahoo.com>
Sent: Thursday, April 05, 2007 4:32 AM


Perfect. Thanks for the ref. Yes, it seems to me that 'synchronicity' of the fore-limbs must come first (before the flight-stroke), although in my personal model synchronicity has it's origins in semi-aquatic locomotion rather than predation. If you watch children running in shallow (mid-thigh or deeper) water, I think you might notice they naturally tend to use the hands in synchronous fashion as they assist the legs by 'pulling ' at the waters surface... they seem to alternate between an alternating stroke and synchronous stroke, the synchronous stroke coming into play when the water is deeper, or when they tire.

This only works when your hands face backwards, and that's not something a saurischian can do.


I like the idea that the wings came first, for brooding (Hopp & Orsen) or whatever.

----- Original Message ----- From: "Dann Pigdon" <dannj@alphalink.com.au>
Sent: Thursday, April 05, 2007 8:54 AM


I envisage the juveniles of some
dromaeosaurs (like *Saurornithosaurus*) spending a lot of time in trees,
avoiding larger predators and perhaps chasing small arborial prey. The
recurved second toe would have made a handy grapple

I disagree. The claw is not round in cross-section. I can't recommend cutting off the twig on which you're standing.


The question would then be whether such behaviour resulted in some early
maniraptor lineages becoming paedomorphic and retaining volancy their entire
life (eventually becoming 'birds'), or whether such behaviour was a case of
ontogeny recapitulating phylogeny (ie. flight being ancestral to
dromaeosaurs, and being reflected in their juvenile stage).

So the question is whether birds are paedomorphic or dromaeosaurs are peramorphic? :-)