The Importance of Being Extinct (was: Re: phyletic bracketing]

["Ken Carpenter" <KCarpenter@dmns.org>]

Basically Jonathan and I are in agreement. Sorry about phyletic, I meant 
phylogenetic. 

I do find it odd that Witmer has removed cheeks from his reconstruction of 
Pinacosaurus, since several ankylosaurs have osteodermal cheek plates preserved 
in situ. Since all ankylosaurs have the same morphological features in the 
cheek region (inset teeth; change in bone texture at the edge of the buccal 
emargination, etc.), it seems more probable that they all had fleshy cheeks. 
Although not as extreme in other ornithischians, they also share many of the 
same features around the mouth as ankylosaurs, so I would argue that they also 
had fleshy cheeks. I have no problem with the argument that they lacked a 
muscular mammalian-like cheek, but to toss out the "baby with the bath water" 
is carrying PBA too far.

Ken

Kenneth Carpenter, Ph.D.
Curator of Lower Vertebrate Paleontology &
Chief Preparator
Dept. of Earth Sciences
Denver Museum of Natural History 
2001 Colorado Blvd.
Denver, CO 80205

Phone: (303)370-6392
Fax: (303)331-6492
email: KCarpenter@DMNS.org

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 http://dino.lm.com/artists/display.php?name=Kcarpenter