Re: Re: CROCODYLOMORPH ENDOTHERMY

[Thomas_R_HOLTZ@umail.umd.edu (th81)]

>>
>> You can say anything you like, but there's no evidence that complete
>> endothermy (or even any kind of endotermy) occurred as early as
>> Ornithosuchia, which by the way is probably the sister-group to the
>> crocodile-normal crurotarsans.
>
>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).

>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.

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