Re: New alvarezsaurid

["Matthew Troutman" <m_troutman@hotmail.com>]

>And if one could prove that alvarezsaurids and oviraptorosaurs had a 
>MRCA than with any other dinosaur, my point would be proven. Oviraptors 
>don't have to be "birds" per se, to be "protobirds", or derived from 
the 
>same stock, both of which diverged so long ago. This would, 
>theoretically, have occured in the Middle Jurassic, with Archie's 
>antecendants, and any form thereafter would be "birds". 
>Maniraptoriformes, for example, as *Oviraptor*, would be derived from 
>the primitive stock that produced Archie on a divergent course, Archie 
>bangs his head against a tree, and WHAM has this sudden urge to give us 
>all a headache and direct his distant cousins to confuse us mammals on 
>avain lineage. Meanwhile, *Oviraptor*, *Shuvuuia*, and *Hesperornis* 
are 
>"birds" and "protobirds".

    I still don't understand how you can dismiss all the characteristics 
that alvarezsaurs share with birds because they have a few superficial 
similiarities with oviraptorosaurs. Oviraptorosaurs lack all the avian 
apomorphies which alvarezsaurs have. Yes, oviraptorosaurs are bird-like 
in some aspects ( scapulacoracoid angle, interclavicular angle, 
anteromedial scapular process, dorsal lips on manual unguals, quadrate 
morphology) but most of these are not unique among Maniraptoriformes and 
can be considered either primitive or convergent.

Are you saying that Hesperornis is not a true bird?

There is no eividence that your hypothesis ( however intriguing or 
compelling ) is true. Oviraptorosaurs and Archaeopteryx sharing a common 
ancestor? This is not true because:

1) They lack many avian features that even dromaeosaurs have.
2) Dromaeosaurs share a common ancestor with the stock that spawned 
Archaeopteryx. 

MattTroutman

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