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Re: HYPSILOPHODONTIDS



First of all, many thanks to everyone who replied! The help is greatly
appreciated!

HP Pete Buchholz wrote:

> Like Mickey said, Drinker was published in Hunteria, which is scarce.
> Speaking of scarce.. so is Drinker....  It bears Tate Museum numbers but
it's
> not at the Tate, and no one there is really clear where it is...
>
*sob*
>
> 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
> Orodromeus.
>
Paraphyletic!?! That would be a serious suprise!
>
> Peng (1990, 1992) has claimed that Agilisaurus louderbacki is closer to
> Lesothosaurus than to hypsilophodontids, but has done so without the aid
of
> cladistic analysis.
>
Hmmmmm.... Recently I did this skeletal reconstruction of Agilisaurus
louderbacki (available on the new and very improved Dinosauricon!) based on
the information given in the paper from the Polygot and when finished all
that I could say
was: Heterodontosaurid! This is at least the conclusion I can make based of
this reconstruction and the information presented in the paper, as well as
some very valuable discussing this with HP Alessandro Marisa. And because
this is no gut feeling or just something based on the impression given by
the skeletal reconstruction, below is given a short character list that puts
it at least as a sister group to the Heterodontosaurids, if not within:

1) somewhat fang-like premaxillary teeth;
2) three _functional_ premaxillary teeth (five are present, but only two as
some small remnants), like Heterodontosaurids but are present also in
Pachycephalosaurs within Marginocephalians, Neoceratopsids have a reduction
to two premaxillary teeth, all other Ornithschia, when present, the
premaxillary teeth are in the number of 5, 6 or 7.
3) the chisel-like cheek teeth;
4) diastema between the premaxilla and maxilla (the premaxilla obscures it
somewhat in Peng's 1992 description, but there is a small piece of it left
to be seen in the figure;
5) 24 presacral vertebrae, like all other Ornithopods, but since
Heterodontosaurids preserve fewer presacral verts, this could be the basal
condition;
6) absence of an obturator process on the ischium;
7) relatively long caudal series;
>
> Rod Scheetz' thesis [on *Orodromeus* ]is availaible through ILL from the
Montana State
> University Library.
>
Is it also possible to order this somehow by snail-mail? Could you please
send me the webadress?
>
> Othnielia is known from quite a lot of stuff.  The gorgeous specimen
> described by Galton and Jensen, is also suplimented by Marsh's specimens
of
> "Nanosaurus" rex (the holotype), as well as "Laosaurus" celer which has a
> partially preserved skull.  I haven't seen anything of it other than 100
year
> old line drawings that are about 1 cm long, so I can't tell you much about
> it.
>
Thanks anyway!
>
Rutger Jansma