Re: "Dinosaurs Died Within Hours After Asteroid Hit Earth..."

[Dora Smith <villandra@austin.rr.com>]

You know, I should know the answer to this, and I don't.   I mostly learned
that hesperiformes and ichthyoformes (sp?) aren't still around.

Did all toothed birds die out before the end of the Cretaceous?

I had the idea some of them were still around in the Tertiary - but I could
very easily be wrong.

Yours,
Dora Smith
Austin, Texas
villandra@austin.rr.com
----- Original Message -----
From: "Mickey Mortimer" <Mickey_Mortimer111@msn.com>
To: <dinosaur@usc.edu>
Sent: Saturday, May 29, 2004 12:34 PM
Subject: Re: "Dinosaurs Died Within Hours After Asteroid Hit Earth..."


> Vlad Petnicki wrote-
>
> > > > And - they had FEATHERS, which turned out to be
> > > > remarkably good insulation against cold - think of
> > > > birds huddling together in a burrow, and you get an
> > > > idea why they survived while the dinosaurs did not.
> > >
> > > *cough* deinonychosaurs *cough* oviraptorosaurs
> > *cough*
> > > segnosaurs ...
> >
> > *Cough* Land-dwelling critters much LARGER than most
> > birds.  VERY UNLIKELY to have been living in burrows.
> > And, given the birds super-light construction, much
> > heavier (thus requiring much more food by an even
> > larger factor than did birds.)  Ever heard of "Occam's
> > Razor"? *Cough*
>
> Basal deinonychosaurs at least seem to have been both small and somewhat
> arboreal.  Maniraptorans were also full of airsacs and hollow bones, like
> birds, so were comparably light.
> This is one of those problems I think we lack the proper data to solve.
> First, only neornithines survived, not other more primitive birds.  So
> people often say we need to find out what was special about them, compared
> to enantiornithines, hesperornithines, etc..  There was quite a diversity
of
> neornithines that survived (galliformes, anseriformes, charadriiformes,
> cormorants, albatrosses, loons), and enantiornithines were very diverse at
> the Maastrichtian too (Avisaurus, Enantiornis, Lectavis, Yungavolucris).
I
> don't think you'll find many ecologically important features the
> neornithines share to the exlusion of Maastrichtian non-neornithines.  We
> have no stable phylogeny for enantiornithines or neoavians.  We don't know
> enough about the various kinds of Late Cretaceous enantiornithines
compared
> to their more complete Early Cretaceous ancestors.  Was Lectavis related
to
> the similarly wading-adapted Longirostravis?  What did the rest of
Lectavis
> look like?  Did enantiornithines live in large flocks?  How common was any
> Mesozoic bird species, and how widespread?  Even if we knew, how rare does
> one species have to be for the K-T event to statistically eliminate it?
How
> many species of each type (this includes tiny deinonychosaurs,
'rahonavids',
> etc.) actually survived to the K-T event anyway?  Just how improbable is
it
> that, assuming that all ornithothoracines were about equally adapted to
> survive the K-T event, only the neornithines would survive?  How well
> sampled are Danian localities for birds?  Could some enantiornithines have
> survived?  Which survival rate is significant enough to be caused by any
> number of factors (chance, better adaptation due to feature A, B, etc.)?
> There are so many questions, many of which I feel can never be answered.
>
> Mickey Mortimer