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Re: Taking measurements

Nick Snels wrote:

<I'm having some problems finding the right way to
measure total skull length in order to compare it to
the relative length of other skull elements. Most of
the papers list total skull length as the length
measured from the tip of the premaxilla or rostral to
the posterior end of the quadrate condyle. But using
this has caused some problems.>

  Absolute length is measured along the longest axis,
from the tip of the premaxilla to whatever; useful for
incomplete skulls as well as complete ones.

  For skulls, length can also be measured from the tip
of the premaxilla to the occipital condyle or to the
quadratic condyles (basal length). The caudal most
expanse of the parietals/squamosals may be useful in
pachycephalosaurs, but the squamosals do in some
species extend farther than the parietals do caudally,
and so _both_ could be used as landmarks. I
personally, for *Stygimoloch* and the Sandy skull,
would measure squamosal and horn length as landmarks,
and measure the overhang and the horns separately, for
reference. The functional, pmx/occ.con. length, is the
one that gives you the skull leverage measurements,
while the basal length is more useful when studying
the jaw itself, not really the skull -- Dodson (1996)
makes a good case for basal length in comparison to
body and trunk length, however.

Jaime "James" A. Headden

"Come the path that leads us to our fortune."

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