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Re: In Re: David's Statements



> <<Maybe I can "explain this away" [by saying] that the actual character
here
> is not the hole in the bone, but the presence of the air sac,
> which may or may not invade the bone due to ontogenetic age or
> whatever. Of course, this is hardly falsifiable...>>
>
> ... and Mickey Mortimer replied (and further in the post):
>
> <Sure..... That will hold up in court.... ;-)>
>
>   Seconding Mickey here, this is not a good position to take.
> Currie is very well respected in his field as is among the [if
> not _the_] top theropod researchers and experts in the world, to
> which Holtz, Molnar, and Chure can add their names. Countless
> hours and weeks in front of the actual specimens has given them
> a considerable experience in telling us if cranial nerve V
> (trigeminal) has a separate exit for the ophthalmic branch,
> which is largely discernible only from within the bone, and for
> _this_ you either need CT-scans to affirm through the lit, or
> personal examination and knowledge of what you're looking for
> [have to admit that the neurology of reptiles is not my
> strongest subject, and I am quickly attempting to remedy that --
> been spending more time working on mechanics and lines of force
> to complete a preliminary set of studies on various things not
> neurologically related fossil-wise].

Oh, I wasn't speaking of the trigeminal nerve's exits. I have no reason to
doubt that *Allosaurus* has a separate exit for branch V1. I was referring
to pneumatic foramina in vertebrae and ribs.

> <<Sure?!? What are double-headed quadrates good for, anyway?>>
>
>   A single-headed quadrate in all taxa that have it lack the
> otic process and do not articulate with the lateral braincase,
> but rather with the suspensorium (squamosal process of the
> quadrate) as so are free to rotate on that head as a hinge; this
> is further enhanced in birds and lacertilians by the lack of
> contact between quadratojugal and quadrate, and only among birds
> do the most primitive forms seem to still bear a contact
> (ligamentous at that) to keep them together. Maniraptora have a
> ligamentous contact here, but with two heads on the quadrate,
> and it would appear that oviraptorids have added a secondary
> contact (quadratojugal peduncle) on the quadrate to reduce this
> condition.

I was referring to the upper (dorsal) end of the quadrate, wasn't I?

> It is secondary in acquisition due to the absence of
> the condition in more basal maniraptorans, or even segnosaurs.

Depends on your phylogeny...

> <<Oviraptorids don't (secondarily?), but Caudipteryx has
> something very much like one (maybe it really has one only 3
> vertebrae long).>>

[snip]

> though is ossified as a "rod," and this suggests the
> union is ligamentous.

Oho! A ligamentous union... Isn't this still more like a pygostyle than the
plesiomorphic condition? :-)

> <<... like the ?nest-parasitizing *Velociraptor* chicks in the
> oviraptorid nest)?>>
>
>   Not a gripe, but a groan ... these skulls have been referred
> to *Byronosaurus* in the recent JVP paper.

Which one?

More answers tomorrow (it's 23:33 over here...)