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Re: dem bones



>Now my question is why can't you tell how the bones ought to be
>connected? (Mind you, I am a student of the humanities working in what
>can perhaps be described as a social sciences organization, and who has
>no background in anatomy). Don't bones line up in one correct way?
>Couldn't you tell about the ribs from their curvature (or what is left
>after fossilization)? I realize that today's new dynamic dinosaurs are a
>departure from what most of us saw in museums as children, but it is my
>understanding that in order to make the bones fit the conception of
>dinosaurs as slow moving tail draggers, they were frequently broken or
>otherwise forced into a position that conformed with the preconception?

The problem with most mounted skeletons is that the ribs are mounted so
that, viewed from the above, they are basically perpendicular with the
vertebral column.  In most tetrapods, however, the ribs are deflected
somewhat backwards.  (Ribs do have a bit of mobility relative to the spinal
column, so they do not show just a single particular angle of
articulation).

Some of the problem with old mounts was based on preconceptions, but some
were simply the mechanical limitations of the materials at the time (steel
and wood, mostly).  Newer mounts can use various plastics (for support,
articulation, and sometimes in place of the bone), and do not have the same
problems.

Only one week left in the USGS.  Good bye, ostracodes; hello,
semi-unemployment...

                                
                 Thomas R. Holtz, Jr.                  Phone: 703-648-5280      
                 Vertebrate Paleontologist         Fax:    703-648-5420
tholtz@geochange.er.usgs.gov ------------>       th81@umail.umd.edu
U.S. Geological Survey          ------------->       University of Maryland
Branch of Paleontology & Stratigraphy ---->       Department of Geology
MS 970 National Center
Reston, VA  22092               ------------->        College Park, MD  20742
                                                          U.S.A.