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Re: Confuciusornis beaks

Christopher Collinson (Chris_Collinson@monarch.net) wrote:

<Is the lower jaw really that bowed? from the photo it looks like the jaw
became disarticulated and is exposed in a ventral aspect, with what the
authors have as the mandibular fenestra is really just the space between
the two rami.>

  In ventral view, the lower jaw has a V-shaped mandibular symphysis, and
the rami stay largely divergent until about 40% along their length, when
they curve into a tighter angle. Flattening appears to splay the symphysis
with an incompletely fused contact so that the rostral-most tip is
slightly separated. This is true of the premaxillae as well, and it
suggests that the feature is an artifact fo flattening. The mandibular
rami are almost never parallel. In lateral view, several specimens show
the presence of the fenestra as a forked posterior dentary adjoining the
dorsal surangular and ventral angular, and both sides of the mandible
showing the same fenestra. It is also apparent in dentaries in ventral
view. So the region is most certainly correct.


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.

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

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