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Re: New Cretaceous bird and other papers



Interestingly HP John Bois cites in his next e-mail an answer from HP Nick
Pharris which I still haven't got. Some server is goofing around...

> > ...there were enants everywhere in the world except in Antarctica in the
> > Maastrichtian. Evidence: All known birds from the Maastrichtian site on
> > Seymour Island (next to the Antarctic Peninsula) are Neornithes.
>
> Underlying discussions of this sort may lurk hefty biases.  Mine is that
> extinction is a complex ecological phenomenon.

(parroting) Background extinction, yes. Mass extinction, no. K-T: One (or
several? Shiva crater?)  big meteorite(s) came down from clear sky and
<BOOM> and Harmagedon, Ragnarök, what have you. (Great time for pyromaniacs,
Hollywood special effect technicians and similar people.) And then the few
survivors diversified idiotically fast and lived happily ever after, er,
until the Eocene-Oligocene boundary. So far my bias. :-)

>  Statements such as yours
> above are music to my ears.

"Wish is the father of thought"
Muhammad

> You are saying (I think) that neornithines
> outcompeted enantiornithines in the Antarctic and (presumably) other parts
> of Gondwana.

Nope. I'm saying that for whatever reasons there were no enantiornithines in
Antarctica, maybe they never got there, who knows. (All my evidence is AFAIK
one site on Seymour Island.) In South America Enanti- and Neornithes appear
to have partitioned niches peacefully -- we have *Enantiornis* and
Avisauridae among the former and *Limenavis* and *Neogaeornis* close to
respectively ?among the latter.

> The "event", then, just greased the wheels for neos,
> facilitating their inevitable global domination a little earlier.

The _event_, then, wiped out the enants, forcing neos to domination in all
niches available for birds which they would still _not_ have reached
otherwise, I claim. There were Neornithes in the USA and Mongolia in the LK.

> So, there is room to entertain
> hypotheses such as this: the prior extinction of most pterosaurs was due
> to bird competition (they _must_ be the prime suspect);

Well. With _so_ little evidence I'd say that's a speculation rather than a
hypothesis. It's testable in principle, but we don't have the necessary
fossils yet.
        Remember the scenario (somewhere in the archives) that there was a
selection pressure for pterosaurs to get bigger, arguing that bigger
albatross analoga are more efficient. That's another possibility. The
biggest flying fish-eating bird known from the entire Mesozoic, AFAIK, is
still *Ichthyornis* -- what competition is that for an azhdarchid???

(Is there any evidence about when *Ichthyornis* died out? Was it or
*Apatornis* or another possible relative left in the late Maastrichtian?)

> if neos outcompeted enantis in the south,
> they _may_ have also done this in the north.

But if they didn't...

> (e.g., now, the image of a falcon snatching
> pterosaur babies, is not outrageous).

If you take the molecular clock estimate for granted. And if you can show
(should be a lot easier) that all the TV shows I've seen of seabird colonies
were overly selective in never showing falconiforms among the numerous nest
raiders.

>  In short, modern birds affected the
> distribution of species _before_ the event.

And suddenly you are in the indicative... :-/

>  In this view, the
> seminal event was not the bolide, it was the appearance of neornithes.

Which obviously explains the extinctions among foraminifers, of ammonites,
of bennettitaleans... :->

> > ...100 % of non-neornithines died out, along with (guesses) 99 % of
> > neornithine species and 99.999 % of neornithine individuals.
>
> As you say, these are guesses. There is no evidence to inform them.

I'm pretty sure that the 100 % are correct -- none are known afterwards --
and that 99 % is more than just in the correct order of magnitude. Guesses,
yes, but not totally without evidence.

> > ...100 % of Neornithes died out everywhere north of (guess) 20° south.
> > Allows for survival of ratites in New Zealand, Madagascar and India as
> > predicted (but maybe not necessary, assuming that the ratites of that
time
> > were not flightless) by the newest mtDNA phylogeny of ratites.
>
> You accept _this_ molecular evidence, then?

This is a molecular _phylogeny_ and linked to a precise paleogeographical
scenario. But, as I said, it may not be necessary that all that really
happened in the K, the ratites may well have flown around later. We just
have 0 fossils from Paleocene ratites outside of Europe... :.-( (Or am I
forgetting a ?rhea from SA? Or is this false memory? ~:-| )