Re: Conservatism of dinosaur brain cases

[Dinogeorge@aol.com]

In a message dated 96-05-30 11:54:57 EDT, jrw6f@faraday.clas.virginia.edu
writes:

>          The parasphenoid is a part of the braincase of bullatosaurs,
>and is considered a high weight novelty by most workers.  I think it
>is very likely that, with enough detailed work, these will be shown to
>be not only homologous, but synapomorphic.  In any case, I think
>Currie's statement goes a long way toward refuting your premise.

Sorry, this is still argument from authority. What >>evidence<< is
there that an inflated parasphenoid (wasn't it basisphenoid?) capsule
couldn't have occurred more than once within Dinosauria?

By the way, I've used the supposed conservative nature of braincase
anatomy myself on occasion. Still doesn't make it right. And besides,
certain evolutionary changes in manual and pedal anatomy might well be
virtually irreversible and thus weigh >>even more<< than one or two
features of braincase anatomy.