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Re: So here it is... my paper, open for discussion (very long; try to view it in maximum window breadth)



David Marjanovic wrote-

> Sure?!? *Allosaurus*?!?

Yes, Allosaurus. :-) Currie and Dong (1994) state "In later theropods,
including Allosaurus, troodontids and tyrannosaurids, the separation is
complete." (pg.2049).

> > and Carpenter and Currie (2000) code oviraptorids as having the
primitive
> condition.
>
> Any chance for a typo in their matrix? :-]

Sure.  Matrices have typos all the time.  I've found dozens in the
Fukuiraptor matrix alone, which is why it's taking so long to get the
details segment done.

> Maybe I can "explain this away" 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...

Sure..... That will hold up in court.... ;-)

>         *Bagaraatan* doesn't go anywhere in my phylogeny, because I lack
> information. Segnosaurs... well, I've put them into Sauropodomorpha with
the
> usual arguments, but this placement has become difficult to defend. Either
> way, one arrives at about 50 synapomorphies and 50 convergences, as
someone
> stated onlist a few years ago on this topic (now in www.dinosauria.com).

I recommend getting a hold of the Bagaraatan article and checking this
little thing out.  So far as I know, only Tom and I have included it in a
phylogenetic analysis, and we disagree as to what it is :-) .  Segnosaurs
should be very important to your hypothesis if you think oviraptorosaurs are
closest to birds, as the two taxa are thought to be sister groups by most.

> Sure?!?
> What are double-headed quadrates good for, anyway?

Yep.  Ji et al. (1998) state, "The single-headed quadrate is vertical in
orientation".  I really don't know the functional significance.

> The tail of *Avimimus* is rather short too, AFAIK.

The tail has only been discovered recently (Watabe et al. 2000), but is
still undescribed.  It was longer than originally figured by Kurzanov
however.

> > There is a difference between the lateral depressions found in the
dorsals
> (confuciusornithids, enantiornithines) and caudals
> > (Patagonykus, enantiornithines) of some maniraptorans and the
pleurocoels
> (pneumatic foramina) found in the sacrals and
> > caudals of caenagnathids and oviraptorids.
>
> Which (other than grade)?

Well, a pleurocoel enters the bone and connects with a cavity in the
centrum, wheras a depression is just... a depression.  Not that one couldn't
evolve into the other, but they should not be taken as the same character.

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

>insert insane laughter here< ;-) Fine, don't believe the authors.  Sure
they're respectable paleontologists, but that doesn't mean they're not blind
(all eight of them- Ji, Currie, Norell, Ji, Zhou, Wang, Zhang and Xu).
Caudipteryx does NOT have a pygostyle.  Sure, the distal caudals are stiffly
held together, but it's the same in lots of maniraptorans.  Okay, I'm done
ranting now...calm down...next paragraph... ;-)

> I haven't addressed the radius of *Microvenator* (I didn't know about it,
> and animals like *Sinornithosaurus*, *Bambiraptor* or -- *Archaeopteryx*
> would decidedly look like better candidates here) and the jaws of
> caenagnathids (AFAIK there isn't much fusion, if any, in alvarezsaur jaws,
> and I have mentioned in the paper that *Oviraptor* has a tiny separate
> coronoid).

Microvenator is very odd in that its radius is very long compared to its
humerus (93%).  This is even longer than Sinornithosaurus (77%), Bambiraptor
(65%) and Archaeopteryx (84-88%).  Only Jibeinia and ornithothoracines have
such elongate radii among theropods.
Alvarezsaurids have yet to have their lower jaws described well, or figured.
Caenagnathus is like some birds in that its surangular and articular are
fused.  As both are labeled in the photos of Shuvuuia's skull (Chiappe et
al. 1998), perhaps they were unfused in alvarezsaurids.

>         How surely identified are the ornithoid *Deinonychus* eggshells?
Are
> there embryos inside (_inside_, not outside like the ?nest-parasitizing
> *Velociraptor* chicks in the oviraptorid nest)?

I'm pretty sure they are just eggshells without embryos, but they haven't
been described yet, so I'm not sure what evidence exists they are from
Deinonychus.

> > - reduced olfactory lobes
>
> As *A.* lived at the seashore, where there aren't too many things to
sniff,
> I'll suspect convergence.

Rob Gay did a good job argueing against this.

> > - less than nine caudal vertebrae with transverse processes
> > - very short anterior chevrons, none taller than anteroposteriorly long
>
> What's the condition in *Microraptor* and *Rahonavis* (wherever the latter
> belongs)?

The number of caudal vertebrae with transverse processes is unknown in
Microraptor, Rahonavis has nine.  Microraptor also has no elongate chevrons,
but Rahonavis has six.  I can ignore Microraptor and Rahonavis though, as
I'm only arguing that Archaeopteryx could be closer to pygostylians than
arctometatarsalians, oviraptorosaurs and dromaeosaurids (none of which
Microraptor or Rahonavis is a member of).

> > - phalanges on third manual digit reduced (III-1 and III-2 sutured, not
> jointed; possibly ancestral to the pygostylian
> > condition of having two non-ungual phalanges on digit III)
>
> Sutured??? Really sutured??? And your phylogeny supports this as being
> reversed in dromaeosaurids???

Yeah, it's odd isn't it?  I actually don't have this character included in
my analysis yet (always work to be done...), but my phylogeny does support
it as being reversed right now.

> > - proximodorsal ischial process
>
> I'll try to have a few looks at theropod pelves, about which I don't
really
> know much.

The only non-pygostylians with the process are Bambiraptor,
Sinornithosaurus, Unenlagia, Rahonavis and Archaeopteryx.  Well, I suppose
sinraptorids have a version of the process too, but they're way down the
tree.

> > - tibia subequal in width and length in proximal view
>
> Sounds like size-related to me.

Doubt it.  Bagaraatan has this character (told you it's interesting :-) ),
with a tibia 365 mm long.  Caudipteryx (182-196 mm), Protarchaeopteryx (160
mm) and Patagopteryx (140 mm) don't, yet have much smaller tibiae.

> > While the akinetic skulls of confuciusornithids could very well be
> secondary, they do possess ascending processes on their
> > jugals (Chiappe et al., 1999).
>
> What's that ref, the JVP paper on *Changchengornis*?

Nope.
Chiappe, L.M., Ji, S., Ji, Q., and Norell, M.A. 1999. Anatomy and
systematics of the Confuciusornithidae (Theropoda: Aves) from the Late
Mesozoic of northeastern China. Bulletin of the American Museum of Natural
History 242: 1-89.

> Hm. I'll wait for the *Protopteryx* paper.

I don't see what's so important about the tails of confuciusornithids,
Jibeinia and Protopteryx that suggests they are a primitive type of feather.
Birds of paradise (Paradisea) actually have "more primitive" feathers in
that sense, as they lack vaned differentiation even at the tip.  The tail
feathers of basal pygostylians are probably secondarily derived, not
primitive.

> Thanks for the good critique!

You're welcome.  Keep up the creative thinking, but be sure it fits with the
facts :-)

Mickey Mortimer