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Re: THEROPOD-BIRD RESPIRATION



GSPaul wrote:

> Archaeopteryx acetabulem -

> On another subject, Larry Martin restores Archaeopteryx with an
extremely thin
> rim of the posterior acetabulem. He uses this feature to justify his
> restoration of the urvogel with a vertical body posture. This is quite

> incorrect. The supraacetabular shelf of the London Archaeopteryx is
fairly
> broad and well developed, more so than those of some theropods,
including
> dromaeosaurs and even tyrannosaurs. There is no evidence that
Archaeopteryx
> walked hither and yon with its body erect.

About 10 years ago, Martin called the posture of Archie "like that of a
primate" ("The case of the flying dinosaur", _NOVA_, PBS videos).
Presumably, according to Martin, this was to afford the animal a center
of gravity very close to a tree trunk.  I haven't heard if he has since
revised his ideas on this.

If Archaeopteryx did have a primate-like posture, it is the only
archosaur known to have had one.  AFAIK, not even pterosaurs had
anything resembling the posture of a primate. (on the video, Martin's
displayed a 3-D reconstruction of Archie; it's posture was *so* upright
that Martin was forced to curl Archie's tail upwards, or risk having the
tail cut furrows into the ground whereever it walked!  Probably not very
healthy for the tail plumage!)  Apparently, Archie could indeed bend
it's tail near the base, but I still find it counter intuitive that the
animal would *always* walk around on the ground with the tail contorted
upward in such a fashion.

                                      <pb>