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HYPSILOPHODONTIDS: MONO-, POLY- OR PARAPHYLETIC
Delayed response to Rutger Jansma's and Pete's comments
on validity of Hypsilophodontidae. Rutger wrote...
2) Naish & Martill thought that the Hypsies and their
relatives do not really constitute a single family, instead,
they thought it was more paraphyletic, with some genera
more closely related to Lesothosaurus, while others more
closely to the iguanodontids. Is this correct?
Naish & Martill write that 'yandusaurs and agilisaurs appear
archaic compared to _Hypsilophodon_ and some of them
may not even be ornithopods' (p. 66). As Pete will tell you
this isn't exactly right but that text was clearly not the place
to discuss views on _'Y'. multidens_ et al. Also, the Naish &
Martill statement does not apply to all things that have been
allocated to _Agilisaurus_ and _Yandusaurus_, but to 'some
Naish & Martill do not state that 'some genera are more
closely related to _Lesothosaurus_'; our implication (though
you'd need psychic powers to know this) is that some of the
taxa involved may be non-ornithopodan cerapodans.
> Mmmm kind of. Although it seems to be the word on the street that
> Hypsilophodontidae is paraphyletic, the only thing that has produced that
> result that is even close to published is Rod Scheetz' phD thesis on
The full results are unpublished but note that there is an
abstract out there..
Scheetz, R. D. 1998. Phylogeny of basal ornithopod
dinosaurs and the dissolution of the Hypsilophodontidae.
_Journal of Vertebrate Paleontology_ 18 (supp. 3), 75A.
Somewhere out there also is a Norman and Barrett MS with
comments on these taxa. I have spoken about it with Paul
but am not sure on its current status. Note that there is quite
a bit of stuff on these taxa in the DML archives and assorted
cladograms have been offered by Mickey M, Pete and
School of Earth & Environmental Sciences
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