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Re: Coracoid/scapula (was Re: flying Archie)

If they go flightless, do they always lose the joint?


----- Original Message ----
From: David Marjanovic <david.marjanovic@gmx.at>
To: DML <dinosaur@usc.edu>
Sent: Monday, September 25, 2006 4:44:18 PM
Subject: Re: Coracoid/scapula (was Re: flying Archie)

>>It would require two more reversals -- in *Sapeornis* and in
>>Confuciusornithidae. Four reversals instead of two or maybe three
> The condition is unknown in _Sapeornis_ and confuciusornithids because the
> suturing/fusion obliterates the nature of the articulation.  Thus, they
> could have evolved from birds with the enantiornithean-style 
> peg-and-socket
> articulation, and the immobile joint could be secondary.  Under this
> scenario, the condition in _Sapeornis_ and confuciusornithids is not a
> reversal.  It would be (and has been) coded as '?'.

Ah, then we aren't talking of exactly the same character. I am talking of 
the joint, which I interpret as having 3 possible states: flat 
(plesiomorphic), coracoid in scapula, or scapula in coracoid. I may be wrong 
in which of these is the plesiomorphy, but the reversals I mentioned all 
require independent losses of the joint.

Neornithes never lose the joint, BTW, unless they lose the ability to fly.