Re: Re: CROCODYLOMORPH ENDOTHERMY

["Nicholas J. Pharris" <pharrinj@PLU.edu>]

On Mon, 29 Jan 1996, th81 wrote:

> >Sorry for the mixup.  I was talking about the clade Ornithosuchia 
> >(proposed to include Euparkeria, Ornithosuchidae, and Ornithodira).  Is 
> >this not widely accepted these days?
> 
> According to more recent cladograms, Ornithosuchidae is a
> pseudosuchian/crurotarsian (i.e., it is closer to crocs than birds), and
> Euparkeria may be the sister taxon to Archosauria proper (i.e., the node
> uniting crocs & birds).

OK.

> >Bone
> >> histology might make me sit up and take notice, but even that is
> >> questionable. We have a hard enough time convincing anyone of dinosaurian
> >> endothermy via bone histology, let alone of thecodontian endothermy, where
> >> the deck is really stacked against it.
> >
> >Oh, really?  Excuse me, but I'm not so sure.
> 
> Have you read the recent papers by (in various combinations) Chinsamy,
> Chiappe and/or Dodson?  These were in Nature, American Scientist, and (I
> think) Paleobiology over the last year.  They throw some (potential)
> spanners into the histology works.

Yes, I've read whatever of theirs I could get my hands on.  We'll see 
about the spanners.  I've seen nothing to upset the 
plexiform/fibro-lamellar dichotomy, and I am very skeptical that the dark 
marks they call "growth rings" really are such.

As for dinosaurs not ceasing to grow, neither do kangaroos or elephants, 
and I have a lot of trouble seeing how such a feature would be related to 
endothermy (or lack thereof).

> Thomas R. Holtz, Jr.
> Vertebrate Paleontologist
> Dept. of Geology
> University of Maryland
> College Park, MD  20742
> Email:Thomas_R_HOLTZ@umail.umd.edu (th81)
> Fax: 301-314-9661
> Phone:301-405-4084
> 

Nick Pharris
Pacific Lutheran University
Tacoma, WA 98447
(206)535-8204
PharriNJ@PLU.edu

"If you can't convince them, confuse them." -- Harry S. Truman