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Bird Origins + Ref:



Phillip Bigelow <n8010095@henson.cc.wwu.edu> wrote on Fri, 2 Jun 1995:

>It would have to be Avimimus (arguably the most birdlike of the non-avian 
>dinosaurs...possibly moreso than Mononychus).

 A fairly recent article suggests that they have an alternative to
"dinosaurs as avian progenitors":

Feducca, A & Wild, R (1993).  Birdlike Characters in the Triassic Archosaur
>Megalancosaurus<.  Naturwissenschaften 80:564-66.

The photo they have of this specimen is the most bird-like of Mesozoic
animals I have seen (please correct me on this!).  The beak and scapula
morphology is so much like a modern bird, it scares me.  I'm not a
cladogram expert (and wish not to be ;-) so excuse what follows.

Feducca & Bird show that the origin of aves can be supported by
synapomorphies (homoplasious) from both the archosaur and dinosaurs.  They
actually strongly suggest that theropods did NOT give rise to the birds,
but are only "related" - I would like opinions on this, but remember I'm
only stating what they have written ;-)

Could this mean that birds (and flight - excluding pterosaurs at this
moment) have evolved twice?  If so then which lineage gave rise to our
modern birds - dinosaurs or archosaurs??????

Sorry I have not mentioned pterosaur in this, but no matter what Bakker
(who?) thinks I will not place pterosaurs in with dinosaurs.

Cheers,

Darren R. Grocke
Vertebrate Biogeochemist
Dept. of Earth Sciences
Monash University
Clayton         Victoria
Australia       3168

Tel: +61  3  9905 5161
Fax: +61  3   905 4903