Re: Jim Davis' dinosaurs

[Dinogeorge@aol.com]

In a message dated 96-01-13 13:34:10 EST, PESELYG@LYNX.APSU.EDU writes:

>Under the BADD doctrine, penguins are dinosaurs (although
>not previously attested at the North Pole), but pterodactyls
>aren't dinosaurs and thus not birds (so Garfield is guilty of
>a *suggestio falsi* on this point)...but what about under the
>BCF (birds came first) doctrine?  Is the point at which the
>term "bird" begins to be applied later than the point at
>which the ancestors of pterodactyls diverge from the ancestors
>of proto-birds?  I would assume so.

Indeed it does. Right now, I have very little clue as to where pterosaurs
diverged from the lineage leading from the common archosaurian ancestor to
the birds. Pterosaurs were such derived animals that any divergence point
from just below Dinosauria all the way back to the common archosaur
ancestor--and even earlier!--is still possible. I'm partial to the
Padian/Berkeley school, which makes Pterosauria a sister group to Dinosauria
within a larger clade Ornithodira, because in terms of posture and hind-limb
architecture, pterosaurs were more erect than thecodontians but not as erect
as dinosaurs, but some anatomical characters suggest a more distant
relationship between pterosaurs and dinosaurs.