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Re: New refs. (and a correction)



>I was wondering
>about that.  I see "hollow bones" in some diagnoses of dinosaur species, but
>I have never seen that character trait used in cladistics.

Phil -

        There is a _big_ difference between a hollow bone and a pneumatized
bone.  Virtually all long bones are hollow; that's just where the marrow
is.  The point of contention with many dinosaurs is whether or not the
hollow areas in some bones were pneumatic cavities -- that is, places where
"air sacs" existed, as in birds.  However, in discussions of theropods, it
often becomes easier to just say "hollow bones" when "pneumatized bones" is
what is really meant; thus the confusion.  Some people have also proposed
that some sauropod bones were pneumatized:  the large hollow cavities in
_Camarasaurus_ vertebrae, for example, have occasionally been cited as
locations for air sacs.  I am not aware that anyone has really proposed
this in any ornithischian.  Obviously, without the preservation of soft
parts, it becomes really difficult to determine whether a hollow space in a
bone contained an air sac or not.


Jerry D. Harris
Denver Museum of Natural History
2001 Colorado Blvd.
Denver, CO  80205
(303) 370-6403

Internet:  jdharris@teal.csn.net
CompuServe:  73132,3372

--)::)>   '''''''''''''/O\'''''''''''`  Jpq--   =o}\   w---^/^\^o

OOO f the Earth's many creatures, not all did survive.
O   O Only those that adapted are today still alive!
OOO Those that couldn't -- or wouldn't -- are with us no more:
The most famous of these is the great dinosaur!
"Evolution," they call it; a 10-dollar word.
That's how nature, in time, from a fish, made a bird.

                                                -- Martin J. Giff

--)::)>   '''''''''''''/O\'''''''''''`  Jpq--   =o}\   w---^/^\^o