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SOME ORNITHOPOD STUFF (FOR ONCE)
Samuel Barnett wrote:
<< 1) The latest news I have on the relationship between iguanodontids and
hadrosaurids (okay so the first question might give you a clue) is from 'The
Dinosauria' Weishampel, Dodson, Osmolska. does anybody know if the
relationships illustrated on page 529 fig 25.36 have been updated since then?
If so can you let me know please with any reading material/web-page links
that may be of some relevence.>>
Yes, there has been a lot published since then on the sticky relationships
within Iguanodontia. Most noteably, on the placement of Tenontosaurus. It
turns out, even the most vocal supporters of an exclusive Tenontosaurus +
Hypsilophontodae clade can't get them to clade together anymore, and
Tenontosaurus always falls out as an iguanodontian more basal than Dryosaurus.
Additionally, new basal Iguanodontoideans (that is; {Iguanodon +
Saurolophus}) seem to be screwing everything up. There are two "camps" in
the debate, one (Norman, Weishampel etc) supports the idea of a monophyletic
Iguanodontidae and a monophyletic hadrosauridae. The other, supported by
Sereno and Forster, conclude that iguanodontids are not monophyletic and are
just a series of outgroups leadign up to hadrosaurs proper. Forster has even
concluded that Iguanodon bernnesartensis and I. atherfeldensis do not even
clade with eachother.
<<2) Are any hadrosaurids known to have had thumb-spikes>>
No
<<or any guanodontids known to have had head crest adornment,>>
One kind of does. Altirhinus kurzanovi has a large nasal crest that is
reminescent of that seen in Gryposaurus. It has long been refered to
(incorrectly) as Igunodon "orientalis", but Norman has shown that the type of
I "orientalis" is just a weird individual of I bernessartensis, and not an
individual of the big nosed species.
<<or any heterodontosaurids, hypsilophodontids, or dryosauridae known to have
either?>>
Dysalatosaurus lettowvorbecki has a weird sagital ridge on its premaxillae,
and Zephyrosaurus and Orodromeus have what appears to be altoids groing out
of the sides of their jugals, but aside from that, there is not much crest
variation.