Re: K-T crocodylians

[Mickey Rowe <rowe@psych.ucsb.edu>]

>From Chris Brochu:

------- Start of forwarded message -------
Date: Tue, 24 Jul 2001 04:32:44 -0400
To: dinosaur@usc.edu
From: chris brochu <christopher-brochu@uiowa.edu>

>Tom,
>     I would think there would have to be an absolute minimum of 5
>crocodyliforms surviving K-T (probably more, but not a large number).
>     At least one crocodylid, one alligatorid, one thoracosaurid, one
>dyrosaurid, plus a baurusuchid and/or a sebecid.  Not sure if any gavialids
>go back that far.
>     I certainly do not agree with statements I occasionally see that crocs
>sailed through the extinction virtually unscathed.  But they certainly seem
>to have done better than birds, as one would expect from the combination of
>coping mechanisms the crocs had.
>                 ---Ken

(grumbles because people are talking about something without going to the
library; there's been recent literature on this.)

There were many more than 5 croc lineages in the Maastrichtian, and many
more than 5 (though some of these are ghost lineages) in the Paleocene.
These seem to be largely the same lineages.  I am giving a talk at SVP this
year partially on this subject (though focusing on patterns of diversity
within the Cenozoic.  It partially addresses recent papers by Vasse and Hua
and by Markwick on the issue; as I am out of town, I don't have references
handy.  They were published in Paleobiology and Oryctos within the past
three years.  I have problems with how these were done, but much of the
overall pattern (if not the internal taxon patterns) is reasonably stable.

Thoracosaurids are gavialoids.

On what basis do you conclude that crocs did not sail through the KT
boundary unscathed?

- ------------------------
Christopher A. Brochu
Assistant Professor
Department of Geoscience
University of Iowa
Iowa City, IA 52242

christopher-brochu@uiowa.edu
319-353-1808 phone
319-335-1821 fax
------- End of forwarded message -------