Re: This week's Nature...

[MKIRKALDY@aol.com]

th81@umail.umd.edu wrote:
>  ...is, according to the "Next Issue" blurb of the Sept. 17 issue, supposed
>  to have an article concerning matters "inside _Archaeopteryx_".  Should be
>  interesting.

Nature 395, 374 - 376 (9/24/98):  "Postcranial pneumatization in
Archaeopteryx" -  BROOKS B. BRITT, PETER J. MAKOVICKY,
JACQUES GAUTHIER & NIELS BONDE

An excerpt:  "Pneumatization of the postcranial skeleton by the lungs
is thought to be a hallmark of the avian skeleton, and to be an adaptation
 for flight by reducing weight. Pneumatic features have, however,
remained elusive in the primitive avialan Archaeopteryx lithographica.
The hollow long bones of Archaeopteryx were first interpreted to be
pneumatized1, but this interpretation was later rejected because of an
absence of pneumatic foramina in these bones that connect their interiors
with the respiratory system2,3,4,5,6. Pneumatic features have also been
recognized in the axial skeleton of many non-avialan theropod dinosaurs
 (and some other archosaurs of the bird clade). The purported lack of
postcranial pneumatic features in Archaeopteryx has been interpreted as
a primitive condition of avialans; this raises doubts about the homology
between postcranial pneumatic features of birds and non-avialan theropods7.
 Here we re-examine two specimens of Archaeopteryx. These specimens
show evidence of vertebral pneumaticity in the cervical and anterior thoracic
vertebrae, thus confirming the phylogenetic continuity between the pneumatic
systems of non-avialan theropods and living birds."

Guess what they have to say about the proposed relationship of birds
to theropods!

Mary
mkirkaldy@aol.com