Re: Birds and archosaurs

[rowe@lepomis.psych.upenn.edu (Mickey Rowe)]

Bill Barbour writes:

>Also, there was some work published early this year which suggested
>that Late Cretaceous birds show growh rings within their bones and may
>have been ectothermic, or at least not totally endothermic.

That would have been a _Nature_ paper published by Anusuya Chinsamy,
Peter Dodson and Louis Chiappe (I hope I didn't misspell anyone or
leave anyone out).  Anusuya was a subscriber to this list, but she
moved back to South Africa at the end of August and apparently hasn't
re-established a connection to the internet.  Before she left, though,
she gave me a bunch of reprints relating to her work on bone histology
of birds and other archosaurs.  I still haven't gotten around to
reading them all, but I can dig them up for you if you want to find
copies for yourself.

>Does anyone know what became of this idea?

It's still being mulled over.  From the histology I've seen, it
appears to be pretty clear that bone formation in theropods and early
birds was different from bone formation in modern birds and mammals,
and ostensibly it was more similar to bone formation in modern
"reptiles".  However, as Stan pointed out, there's still room for
debate over the apparent bone growth pattern's significance with
respect to physiology.

-- 
Mickey Rowe     (rowe@lepomis.psych.upenn.edu)