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Re: Copeing with mammals



----- Original Message -----
From: "John Bois" <jbois@umd5.umd.edu>
Sent: Monday, November 22, 2004 5:22 PM

Pterosaurs clearly had issues.  As a clade, their extinction was long and
slow.  This argues against a long series of accidental extinction events.
It argues _for_ some kind of deficit relative to other clades.

How? How does it?

I have proposed a reasonable problem--that juveniles (or adults, for that
matter) were not as agile in the air as neornithines, and were therefore
more susceptible to predation/general harrassment.

But you haven't provided any shred of evidence for this speculation.

You seem to be arguing that flying ability doesn't enhance
competitiveness; or that even if neornithines _were_ better fliers they
somehow gave the pteros a free pass.

The keyword is "if". Not to mention the problems associated with evolving into an occupied niche.


But what are you arguing?  That each pterosaur species extinction was
unrelated, caused by a separate environmental whim?

I argue that this is possible -- although there's no evidence either way. However, never forget how poor the fossil record of pterosaurs in the LK is. We don't _know_ if _any_ pterosaur clade that is known from the EK went extinct before the K-Pg boundary. The most extreme examples are the anurognathids: although known from the MJ to the EK, they have to date _only_ been found in Konservatlagerstätten. Outside they seem to have left _no trace_ across some 60 million years!!! I don't know of a LK Konservatlagerstätte.