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Re: Orenstein's pedestrian arguments.



On Mon, 24 Feb 97 09:41:42 PST, Stan Friesen wrote:

>Good point. I know of no likely true fossorial archosaurs, with the
>one - maybe - exception of _Mononykus_.
>
>[And I have doubts even about that one].

I find it almost impossible to believe that this creature was
fossorial - except for the wierd forelimbs it seems totally unsuited
to such a life (though _conceivably_ it could have tunneled for
nesting purposes).  I suspect (with no evidence) that the forearms
were used for some sort of interspecific aggression, like the spurs on
the wings of jacanas - it would be nice to know if Mononykus was
sexually dimorphic in this regard!

>Hmm, you reinforce my judgement that many small dinosaurs could be
>at least partly arboreal.  This example even helps counter some of the
>objections based on the stiff tails of advanced coelurosaurs.  A more
>unlikely tree-dweller than a lyrebird I can hardly imagine.

Absolutely.  It is quite remarkable how easily the right kind of bird
can get around in trees by wing-free leaping  - have seen birds like
the NZ Kokako and various birds-of-paradise do this, too.  If they
could, why not small dinosaurs?  The stiff tails might actually have
been useful balancing rods, for that matter.

>
> > Highly important as I suggest.  Other burrowers include some petrels,
> > motmots, some swallows, some parrots (eg the Burrowing Parrot or
> > Patagonian Conure of southern South America), some kingfishers,
> > a few woodpeckers and probably others that I have forgotten.
>
>I belive the pygmy owl of the Sonoran desert may be a (limited)
>burrower.

Ummm - I think you mean the Elf Owl, which nests in Saguaro cactus
holes (but does not dig them) or perhaps the Burrowing Owl, which does
dig burrows.  The Pygmy Owls are different again.

Other burrowing birds include a number of songbirds: miners and
pardalotes, for example.

>Which just shows that general anti-predator adaptations are more
>important than flight per se.  So this is actually good support for
>*your* position on the (relative) unimportance of flight in this
>regard.

I agree that the Guam case is hardly an argument for the value of
flight!  However, this sort of rapid destruction of a naive fauna may
not have happened very often before we started shipping creatures all
over the place.