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Ichthyornis Predentary?



Darren Naish wrote of the suggestion that *Ichthyornis* probably didn't have a
predentary, forwarding the idea that this was neomorphic to ornithischians
exclusively within dinosaurs (it would be neomorphic even if convergent, but
that's not the point); Clarke's thesis is clear on the matter (pp. 145-146), in
which she notes that, while inferred for *I. dispar* on the basis of description
in *Hesperornis* and *Parahesperornis,* its presence is absent and apparently
the mandibular rami were well-capable of articulating without leaving a facet or
fossa that would accomodate a predentary, as noted for *Hesperornis* (Martin,
1987). *Ichthyornis,* despite the absence of further descriptive commentary on
hesperornithids, lacked a predentary bone.

Martin, L. D. 1987. The beginning of the modern avian radiation. _Documents des
Laboratories de Geologie_ 99: 9-20.

  Cheers,

  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)