Re: dimorphism

["Jaime A. Headden" <qilongia@yahoo.com>]

And this is all providing you do two things:

  1. can safely determine that in one species, males and females belong to two 
different class
sizes, that is are size-based dimorphic.

  and 2. can determine that even among two species, this ontogenetic "rule" 
holds true.

  What can be determined for one species does not neccesarily hold for another. 
_Large_ sample
sizes in various croc species and alligatorids shows that in fact, there are 
some differences in
the ontogenetic series betweenn sexes _and_ species.

  Another problem is figuring out if there are any extant correlates from which 
to determine sex
and ontogeny (does anyone remember the whole *Procheneosaurus*/*Cheneosaurus* 
mess which resulted
in varies species derived from the contogenetic series (and theoretical sex 
dimorphism) among thre
taxa ... *Lambeosaurus* and *Corythosaurus*, as well as one valid species 
(type) of *Chenosaurus*,
which lacks a skull. Not only that, species of *Corythosaurus* have been named 
on the bases of
skull size and crest shapes, now all sunk into *C. casuarius* ??

  You need data sets. Lots of it. Then look into it for patterns. Match 
patterns to criteria like
discriminnt point analysis and comparative morphology. Determine patterns. 
Compare to extant taxa.
And for all of our sake ... DON'T ASSUME _ANYTHING_. Thankfully, people are out 
there doing their
Masters and Bachelors degrees on these things, but in small groups (Of course, 
even such an
anlysis for skulls _alone_ in ceratopsids may take two whole theses).

  Work work work ... it's a surprise some students have a hard time picking (if 
they have a
choice) a thesis subject. There's tons to do out there.

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

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