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Re: What group has the most work that needs to be done?

David Marjanovic (david.marjanovic@gmx.at_ wrote:

<That's true -- by definition. And this doesn't tell us anything. We don't have
a good idea currently on whether anything else is a hypsilophodontid,
respectively where else all those hypsilophodontids in the classical sense are
on the ornithopod, wait, cerapod tree.>

  Cerapod? But anyway, who uses Cerapoda anymore? You mean Neornithischia,

  My comment about *Hypsilophodon* is oversimplified for a reason. We have
detailed osteological information that shows its gradient relative to
thyreophorans and ornithopodans. Heterodontosaurs appear more basal, and of
course iguanodontians (whatever those are) are more advanced, and what about
tenontosaurs? We have details of the osteologies of all these particulars, so
we know what they ARE. The problem is getting out of a phylogenetic tree
extensive enough to comprise them all in sufficient resolution with enough
character sampling than some of the recent "hand claded"-sized trees we've been
getting from Godefroit, etc. The problem is that the ones I've seen are
unpublished, or require extensive checking to confirm BEFORE publication.
Meaning, this part of the ornithischian tree is still "choppy" and "pick and
choose." Sereno's 1999 analysis remains the only comprehensive research, and
even then it uses suprageneric OTU's, so the resolution is not fine enough.

  So while we know what *Hypsilophodon foxii* is, we do not know precisely
_where_ it is, phylogenetically speaking. This has more to do with other taxa
than with *Hypsilophodon*, such as tenontosaurs, parksosaurs, heterodontosaurs,
and the mass of complexly arrayed species called "Hypsilophodontia," some of
which are probably not ornithopods or neornithischians at all.


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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