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I'm wondering if you are impressed by any of the putative synapomorphies given by Dave Peters, who cladistically nests Longisquamidae within Protopterosauria, a subclade of Ichthy-"something", subclade of Tapinoplatia, subclade of prolacertiform archosauromorphs.
Do any of the particular characters he lists make you lean toward an archosauromorph placement, as opposed to an alternative placement (such as in lepidosauromorpha or among non-Saurian diapsids).
Cheers, Ken Kinman
P.S. Oh, by the way, any opinion on whether the phenetic gap between Poposauridae and Sphenosuchidae is much bigger or smaller than the phenetic gap between Sphenosuchidae and basal Crocodyliformes?
From: chris brochu <cbrochu@fmnh.org>
Reply-To: cbrochu@fmnh.org
To: dinosaur@usc.edu
Subject: Re: Archosauromorph classification & Thecodonts
Date: Wed, 21 Jun 2000 14:12:14 -0500

> Likewise, I will leave Longisquamidae and Sharovipterygidae as >incertae sedis within this order unless it shown they belong elsewhere. >They appear to be archosauromorphs,

I'm not sure I agree.  I've seen Longisquama up close, and most of the
"characters" shared in common with archosauromorphs could be just as easily
interpreted as postmortem damage.  It's probably a diapsid of some sort,
but that's as far as I would go.  One more reason why I no longer use
Linnean ranks.


---------------------- Christopher A. Brochu Department of Geology Field Museum of Natural History 1400 S. Lake Shore Drive Chicago, IL 60605

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