Re: Pro(to)avis

["T. Michael Keesey" <keesey@gmail.com>]

> At any rate, this taxon [hypothetical first bird] probably lived sometime in 
> the late Triassic or
> earliest Jurassic. 

If we are defining "bird" as the Archie-modern bird node-based clade,
then I would not be surprised if the last ancestor existed as late as
early Late Jurassic (say, Oxfordian)--as has been noted,
_Archaeopteryx_ is probably not terribly different from it--several
million years should be easily enough to derive it, right? (Especially
with presumably short generation times for such a small dinosaur.)

I would be very surprised if it existed in the Triassic, since there
aren't even any noncontroversial tetanurans from then, let alone
coelurosaurs, maniraptoriforms, maniraptors, eumaniraptors....

—Mike Keesey