Re: Dinosaurs and birds

[David Marjanovic <david.marjanovic@gmx.at>]

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? :-)