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Re: *Utahraptor* and Polyphyly of Recent Dromaeosaurids



Jaime Headden wrote-

> <<1. fused interdental plates;>>

>   [Sinornithosaurus:] in the matrix. The paper does not mention
> them, and the medial view of the dentary in the type (IVPP
> V12811) does not show them, which is peculiar. >snip<
> They look like they're there, though. Irrelevant, however,
> considering parsimony considers the group == { *Dromaeosaurus* +
> *Deinonychus* } is still validated by this feature; as Xu et
> al., suggest, *Sinornithosaurus* is outside Dromaeosauridae
> using Currie's definition.

Well, I was assuming this was part of the evidence advocating a monophyletic
Dromaeosauridae (presumedly including Sinornithosaurus, Bambiraptor,
Unenlagia and Microraptor).  But you're right, it does still work for
Dromaeosauridae sensu stricto.  Actually, the supplementary information
mentions the interdental plates- "and the interdental plates are present,
but most of them are not fused."

>   The condition is the opposite in oviraptorids (the rostral
> process is covered by the subnarial process of the premaxilla),
> and the caudal process is an extension of the medial extension
> on the cranial roof, so they are not analogous. >snip<
> *Dromaeosaurus* does not possess complete lachrymals or
> profrontals even, so the condition is very problematic. My boo
> for using this as a dromaeosaurid character, but it seems
> equivocal either way.

I'm not sure I know what you mean by "an extension of the medial extension
on the cranial roof", but what do you have to say regarding the triradiate
lacrimals of Caudipteryx?  These look very dromaeosaur-like to me.
* Details on Caudipteryx will probably be completed tonight.  It's huge.
You're right that Dromaeosaurus does not have complete lacrimals or
prefrontals.  I just assumed Currie's (1995) figure 3J (fragment of left
prefrontal (region anterodorsal to orbit) in dorsal view) indicated its
presence.

> <Not examined in most taxa, but also present in Patagonykus and
> Mononykus.>
>
>   Then synapomorphic for both groups, but unless you're arguing
> monophyly of *Velociraptor* + *Mononykus*, this is not
> autosynapomorphic of them, and is convergent under most recent
> analyses.

What I was getting at is the low number of taxa this character has been
examined in.  Basal avians and troodontids have yet to be examined, so it's
more parsimoniously seen as a paravian character until proven otherwise.

Mickey Mortimer