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Combined answer Archaeopteryx running...



Comments to 2 posts from HP Jim Cunningham:

> As you no
> doubt know, modern birds can fly in cruise gaits with their
> supracoracoideus
> cut through (meaning that it is even less useful than in archie).

They just can't gain height any longer. No idea whether Archie's deltoideus
would suffice.

---------------------------------------

> > Now we're talking 'cruising'.  For a primitively poor flier that
> > couldn't flap well, this would just be 'gliding', wouldn't it?
>
> No.  [...] And what would
> make you think he was primarily a glider?  His glide ratio isn't
> as good as that of a pigeon; it isn't all that bad either, but I
> wouldn't expect him to make a living at it, just like a pigeon isn't
> good enough at to make a living with it.

There's even a calculation -- but it only takes into account the weight of
the tail, not its area, and the assumed wing area is debatable -- that
Archie would have reached about 12.9 m/s during gliding. The impact would
_hurt_...

Klaus Ebel: On the origin of flight in *Archaeopteryx* and in pterosaurs, N.
Jb. Geol. Paläont. Abh. 202(3), 269 -- 285 (December 1996)

> > ......opposed to ........ "_Archaeopteryx_-grade" avians.  The latter
> > did (apparently) persist until the end of the
> > Cretaceous (_Rahonavis_); but they were outnumbered
> > (and outcompeted) by the upstart pygostylians.
>
> Since they lasted till the end of the Cretaceous, it may not have been
> the pygostylians what done um in.

I agree. What could have competed with the specialized *Rahonavis*?