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RE: Koreanosaurus, new burrowing ornithopod [Meta]
Anthony Docimo <firstname.lastname@example.org> wrote:
> > Unless _Koreanosaurus_ is included in a phylogenetic
> analysis, then any discussion of its relationships is just
> on the contrary. if that were true, then nobody here
> would be calling it an ornithopod.
I'm only calling it an ornithopod because the paper calls it an ornithopod.
The paper calls it an ornithopod because they list certain characters that
_Koreanosaurus_ has in common with ornithopods. But the paper specifically
calls _Koreanosaurus_ a 'basal ornithopod', which puts _Koreanosaurus_
uncomfortably close to Marginocephalia, as well as uncomfortably close to
non-ornithopod genasaurs like _Othnielosaurus_ (which lies) outside the
Personally, if the authors are going to explicitly link _Koreanosaurus_ to
_Orodromeus_ or _Oryctodromeus_ in a phylogenetic sense, then I would really
prefer to see this hypothesis tested.
> (we'd all be terrified of repeating the mistake of confusing a dinosaur
> with a turtle (ie Therizinisaurs))
Sorry, you lost me here. I know _Therizinosaurus_ was originally misidentified
as a turtle. Phylogenetic analyses have recovered _Therizinosaurus_ within the
Theropoda, close to _Segnosaurus_, _Alxasaurus_, etc. That would seem to bear
out my point regarding the necessity of using phylogenetic analyses to
> we know it's a dinosaur, we know it's an ornithopod, we
> know it isn't a maniraptor or pterosaur.
No, we don't know it's an ornithopod (see above). But even if _Koreanosaurus_
is an ornithopod, that doesn't tell us very much. Is it most closely related
to _Orodromeus_ and _Oryctodromeus_? This has repercussions for the question
of whether fossorial adaptations evolved only once in Ornithischia.
> so why can we talk about what it may be similar to, but
> the discoverers/describers can't?
Well, the describers provide a cladogram that shows _Koreanosaurus_ as sister
taxon to _Orodromeus_ within the Ornithopoda. I'm u
n into a cladogram unless the relationships of the taxon have actually been
tested. Yeah, _Koreanosaurus_ is probably a true ornithopod, and it might
indeed be most closely related to _Orodromeus_ and/or _Oryctodromeus_. But
only taxa that have been plugged into the matrix should be shown in a
cladogram. Otherwise it's misleading.