Re: Ruben Strikes Back

[Dinogeorge@aol.com]

In a message dated 9/23/99 11:43:25 AM EST, eamalitz@hotmail.com writes:

<< Do the 
 experts uniformly support a size compression along the coelurosaurid line or 
 is just an artefact of sampling. Are the tyrannosaurs secondarily 
 re-enlarged then? >>

Absolutely do not support size compression in evolution of theropods to 
birds. It is >much< more likely that flight evolved in small archosaurs that 
adopted an arboreal lifestyle and stayed small until true flight evolved in 
their clade, taking full advantage of light weight and gravity assist for 
gliding. The familiar theropods are much more likely to be large, flightless 
descendants from various nodes along this lineage, and features such as 
"weird hallux" and maniraptoran forelimbs are spandrels left over from 
smaller, more volant ancestors with perching feet and well-developed wings. 
This kind of evolution (of secondary flightlessness) has occurred repeatedly 
in numerous avian lineages and there's no reason to imagine that it didn't 
occur during the early Mesozoic as well. Fully expect feathered Triassic 
archosaurs and am really pleased to see that they're beginning to turn up.