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Re: Coracoid/scapula (was Re: flying Archie)
David Marjanovic wrote:
I don't think it is primitive. ?Within Enantiornithes itself, *Protopteryx*
has a flat joint (no peg, no socket). I forgot about *Jibeinia*. The
confuciusornithids have fused scapulocoracoids, and *Sapeornis* has a
suture (which would possibly have fused with age)... That makes 3: the
assumption of convergence is more parsimonious than that of several
I'm not sure what you mean here. What "convergence" are you referring to?
How about this scenario.... the immobile scapulacoracoid is primitive, but
enantiornithines and euornithines evolved peg-and-socket articulations
independently (athough with opposite configurations); and the flat joint is
an intermediate step between the immobile joint and the peg-and-socket
Some modern bird species (representing galliforms and paleognaths) show a
flat joint too.