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RE: At long last! Turner, Makovicky & Norell on dromaeosaurids
This may be my fault. I may have started this by saying that Incisivosaurus
(the most basal known oviraptorosaur) is not very flighty. Then someone
compared Incisivosaurus to Protarchaeopteryx. What I meant is that
Incisivosaurus is big and relatively heavy.
Incisvosaurus' skull is 11cm long, while Sapeornis' skull is 6 cm long (IVPP
V13275 and IVPP 13276) and Protarchaeopteryx is 7 cm (NGMC 2125).
And, yes, that is interesting about Sapeornis moving down the phylogenetic tree
in Turner et al. 2012.
From: owner-DINOSAUR@usc.edu [owner-DINOSAUR@usc.edu] on behalf of Tim Williams
Sent: Thursday, August 23, 2012 8:53 PM
Subject: Re: At long last! Turner, Makovicky & Norell on dromaeosaurids
David Marjanovic <email@example.com> wrote:
>> _Protarchaeopteryx_ might have been some form of parachuter or
> What, at that size? Isn't it way bigger than any known parachuter and at
> least the size of the very largest known gliders?
But would _Protarchaeopteryx_ have weighed any more than _Sapeornis_?
BTW, I'm not suggesting that _Protachaeopteryx_ was an accomplished
parachuter or glider. I also very much doubt that it was arboreal.
But if there were long, symmetrical feathers along the forelimbs, it
might suggest some "passive" aerial ability.
Speaking of _Sapeornis_, Turner &c recover this taxon as more basal
than _Jeholornis_, _Jixiangornis_ and confuciusornithids. This means
that the pygostyle of _Sapeornis_ evolved independently of that of
pygostylian birds (avialans), including confuciusornithids and
ornithothoraceans. Yet, the shoulder anatomy of _Sapeornis_ is more
primitive than that of the long-tailed _Jeholornis_ and
_Jixiangornis_, and the foot appears far better adapted for perching.
The early evolution of avialans was a weird place to be.