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Cosesaurus (was Protoavis and Megalancosaurus - and the ABSRD model of bird origins)

At 15.52 08/02/01 -0600, you wrote:
  The Prolacertiformes (= Protorosauria - could someone set 
>me straight if these two groups aren't the same) have spawned another 
>alleged proavian in the past: _Cosesaurus aviceps_.  This little 
>archosauromorph (redescribed as a juvenile _Macrocnemus_, the last I heard) 
>was also once regarded as an ancestral avian on account of its rather 
>bird-like head and long limbs.

Cosesaurus was considered a juvenile Macrocnemus by Sanz & Lopez Martinez
1984, Geobios 17. However, it does show an elongate fifth toe (short  in
Macrocnemus) and other features testifying that it does not belong  to
Macrocnemus, while it is possibly related to more advanced prolacertiforms
like Langobardisaurus + tanystropheids. A re-analysis of this tiny reptile
can be found in Peters 2000, Rivista Italiana di Paleontologia e
Stratigrafia 106(3). Interestingly, Peters puts Cosesaurus close to
pterosaur ancestry.

                                        Silvio Renesto 


"Before being enlightened,   hard work; after enlightenment, hard work"
(Guo Yunshen).

Dr. Silvio Renesto
Dipartimento di Scienze della Terra
Università degli Studi di Milano
via Mangiagalli 34
I 20133 Milano

phone +39-0223698232
fax  +39-02-70638261

e-mail:    renesto@mailserver.unimi.it

or/and     Silvio.Renesto@unimi.it