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Extinction once again (was Re: ARE ORNITHOPODS BORING?)



> > I miss something here... the mihirung (Dromornithidae), giant flightless
> > birds of Eocene -- Pleistocene [of] Australia, which were just found 
> > out to be _carnivorous ducks_, with enormous beaks much like *Gastornis*
> > ("*Diatryma*").

I should have mentioned that *Bullockornis* is now called The Demon Duck Of
Doom.

> I, too, miss something: breeding collapse in duck populations of the
> pothole region provides a great model for same at the K/T.  As wetlands
> dry up, this is known to increase predator access, i.e., predation on
> nests is the proximal cause of this collapse.  Guess what happened at the
> K/T: sea level fell, draining possible prime wetland nesting habitat for
> non-avian dinosaurs.

Wrongo!
1. This regression took _4 million years_, spanning quite some time before
and after the K/T.
2. Due to some odd effects of earth axis precession or so (I can dig up the
ref later), sea level dropped in the western half of the northern and the
eastern half of the southern hemisphere whereas it rose in the rest of the
world. Yet the extinction was global.
3. You are not trying to suggest that ALL Maastrichtian non-_neornithean_
dinosaurs nested in "wetlands"!?!
4. Lots of terrestrial egg-laying vertebrates survived (turtles, crocs,
lizards/snakes, tuataras, monotremes...)...
5. Marsupials, for example, were severely hit. How come?
6. Plankton (and all animals with planktonic larvae) was severely hit, which
is not easy to explain with a regression. And the common argument that a
regression diminishes the shallow seas is not entirely correct -- today,
shallow-water taxa always have representants around cone-shaped volcanic 
islands,
around which the area of shallow water increases during a regression.
And so on.

I can't now dig up the reference for "It's difficult to see how a regression
can kill _anything_"; I think this was quoted in Night Comes to the
Cretaceous.

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