Re: EARLY BIRD EVOLUTION

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

>But it is also true that the dinosaurs also share nonflight features 
with >birds not present in Archaeopteryx. For example, dromaeosaurs were 
>more avian in lacking the ectopterygoid process of the pterygoid, 

If I remember correctly, no enantiornithine or any other primitive bird 
up to _Hesperornis_ actually has the palate preserved well enough for 
this to be proved.  

>and having well developed metotic struct posterior to the fenestra 
>ovalis in the middle ear,

Uh.  Actually the metotic strut borders the caudal end of the fenestra 
PSEUDOROTUNDA, rather than the fenestra ovalis.  The metotic strut 
borders caudal margin of the fenestra pseudorotunda, while the crista 
interfenestralis borders the posterior fenestra ovalis.  Anyway, from 
the figures that I have show metotic and crista formation being roughly 
the same in dromaeosaurs and _Archaeopteryx_, with _A_. having a longer 
processes.

>cervical ribs that do not overlap, a

Larry Martin describes the cervical ribs of _Archaeopteryx_ as unfused 
and elongate, but not overlapping.  This is a feature probably related 
to the fact that the cervical vertebrae of _Archaeopteryx_ are 
proportionally shorter than other theropods.  

>more retrtoverted pubes,

Some can argue with this feature.  Dromaeosaurs do not show pubes with a 
hypopubic cup.  Anyway, it is really not for sure that _Archaeopteryx_ 
does not have a highly retroverted pubis.  Some have questioned the 
position in the _A. bavarica_ specimen (pers. comm.). 

<<and a more reduced calcaneum.>>

This is a rather piddly character to be frank :-) 

<<Some of the birdy features of Archaeopteryx are minor and almost 
approached in bird-like theropods.>>

Its a rather big 'almost'.  

<<For example dromaeosaur palatines are almost triradiate, the fourth 
process is vestigal.>>

Not from the figures I seen and as what has been described by Elzanowski 
and Wellnhofer, Currie, and the AMNH group.

<<The phylogentic problems posed by early birds and potentially 
bird-like theropods are complex and intricate, and not subject to simple 
analysis.>>

No argument here.   


Matt Troutman 
m_troutman@hotmail.com


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