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Re: Dinosaurs Breathed Like Birds
> Date: Sat, 16 Jul 2005 04:59:16 +0000
> From: Michael Mortimer <email@example.com>
>> Sauropods (and other sauropodomorphs) have pneumaticized bones--it
>> is a saurischian or eusaurischian trait.
> Er... I'm unaware of any sauropodomorphs more basal than eusauropods
> having pneumatized bones. Some basal forms have hollow bones, but
> these have no connection to air sacs.
Matt Wedel briefly discusses pneumatic structures in the cervicals of
_Thecodontosaurus caducus_ in:
Wedel, Mathew J. 2004. The origin of postcranial skeletal
pneumaticity in dinosaurs; pp. 443-445 in J. Buckeridge and
Y. Chen (eds.), Proceedings of the 19th International Congress
of Zoology. China Zoological Society, Beijing.
Not the easiest publication to get hold of, perhaps, but I'm sure he'd
be happy to send you a reprint. The relevant section is as follows
(from a pre-publication ms., so the final version may differ a
The Late Triassic (Norian) forms _Thecodontosaurus
caducus_ and _Coelophysis bauri_ are the
earliest-diverging sauropodomorph and theropod,
respectively, with unequivocal evidence of PSP [=
Postcranial Skeletal Pneumaticity]. _T. caducus_ and
_C. bauri_ may have inherited systems of pneumatic
diverticula from a common ancestor, but they are the
first representatives of their separate lineages in
which the diverticula invaded the postcranial
skeleton. _T. caducus_ differs from other species of
_Thecodontosaurus_, and from all other prosauropods,
in having sharp-lipped cavities on the lateral sides
of cervical vertebrae six through eight (Yates, 2003).
The placement of these cavities on the vertebrae,
their invasive nature, and the presence of a sharp lip
of bone bounding each cavity, all argue for the
interpretation of these cavities as pneumatic in
origin. Pneumatic cavities of this sort do not
reappear in sauropodomorphs until the advent of basal
sauropods, such as Shunosaurus, which have pneumatic
Hope this helps.
/o ) \/ Mike Taylor <firstname.lastname@example.org> http://www.miketaylor.org.uk
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