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

[Mickey Mortimer <Mickey_Mortimer111@msn.com>]

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