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Re: Looking for patterns in extinctions.



>died too (including dinosaurs).  In addition, when one considers
>that the overwhelming number of creatures over 25kg. _were_ the
>dinosaurs, the claim becomes tautological.  The point is that
>there is no pattern here, only the _fact_ of dinosaur extinction.

Nonavian dinosaurs, that is.  Okay, non-neornithine dinosaurs, to be
precise.
 
>3.  Well, anyway, here is a pattern which explains survivors as
>well as losers.  Things that survived the K/T were stealthy egg
>layers (birds, snakes, turtles, and lizards), non-egg layers
>(most mammals), and crocodiles (niche sovereigns).  Things that
>didn't make it were non-stealthy egg-layers, i.e., the dinosaurs. 

Not to burst your bubble (okay, to burst your bubble):

How does this account for the extinction of the toothed bird lineages?
In what ways were the nests of neornithines, basal ornithurines,
enantiornithines, and small nonavian theropods different?  Nesting in
trees is NOT a primitive avian feature (anyone know of a tree nesting
ratite?).

For that matter, in what way were the nests of the various dinosaur
groups, crocodilians, lepidosaurs, and turtles different?  (Okay, the
two archosaur groups covered the nests with vegetable matter).

Why did the North American marsupials die, but those in other regions
survive (the Virginia opposum, by the way, is a migrant from South
America)?

And most importantly, what does any of this have to do with the main
event: the extinction of the Mesozoic marine fauna and flora?

Thomas R. Holtz, Jr.
Vertebrate Paleontologist     Webpage: http://www.geol.umd.edu
Dept. of Geology              Email:th81@umail.umd.edu
University of Maryland        Phone:301-405-4084
College Park, MD  20742       Fax:  301-314-9661