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Re: K-T crocodylians


Chris,
I will certainly concede that the Notosuchians may have croaked well before K-T (but who knows, absence of evidence is not...).
But both Peirosauridae and Paralligatoridae apparently made it to the Maastrichtian (see Mike Benton's site, which is presumably based on Fossil Record 2). So I would add those to Goniopholididae as three whole families that may have croaked at K-T.
The crown group crocs did a lot better, but I seriously doubt that they sailed through K-T unscathed. Endemic species from southern North America to northern South America probably never had a chance to even try to cope. They were probably a lot luckier than many croc species further away that suffered a slow death from acid rain, disease, cold, and other unpleasantness (as opposed to Central American forms that died quickly). Crocs in Antarctica and Australia may have gotten by "relatively" unscathed, but personally I wouldn't be surprised if there were croc extinctions there as well (along with *ALL* the non-avian dinosaurs even down there). Some crocs probably had a really good time chomping down on all those dead bodies, but as a group "unscathed" is not a word I would use. [I would have rather been a small shark or sea turtle in the Indian Ocean, or better yet a buried frog in torpor sleeping through the whole thing].
Is K-T depressing or what,
Ken
****************************************** 
From: chris brochu <christopher-brochu@uiowa.edu>
Reply-To: christopher-brochu@uiowa.edu
To: dinosaur@usc.edu
Subject: Re: K-T crocodylians
Date: Wed, 25 Jul 2001 05:49:28 -0400


> At least I'm glad you admit that Goniopholididae may have been among
>the extinctions at K-T. What about Peirosauridae and Paralligatoridae? Or
>are those families cladistically unacceptable taxa?


As far as I know, the records for these groups don't make it up to the
Maastrichtian.  Same with notosuchians (monophyletic or not) - it's rather
hard to claim that they croak at the kt boundary when their last appearance
datum is well below the kt boundary.


------------------------
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




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