Re: Classification questions

["Thomas R. Holtz, Jr." <th81@umail.umd.edu>]

At 02:36 PM 8/20/97 -0400, T. Mike Keesey wrote:

>-Is Macronaria stem-based or node-based? If stem, it could be different
>from Camarasauromorpha.

According to Sereno (1997) is that it is node-based, but it could be "saved"
by using a stem-based version.

>Also, has Macronaria been published yet?

Only "official" use so far is in Sereno's (1997) paper in Annual Review of
Earth & Planetary Science.  It will formally be proposed in a
soon-to-be-published (hopefully) paper by Wilson & Sereno.

>Should I be using it? Same goes for Carnotaurinae.

Good questions.  Carnotaurinae has not formally been proposed yet.

>-Have there been any recent studies on the internal structure of these
>families?:
> Spinosauridae

Not yet, beyond the suggestion (in Kellner, A.W.A., 1996. Remarks on
Brazilian dinosaurs. Memoirs of the Queensland Museum 39(3): 611-626) that
the Brazilian spinosaurids might be closer to _Spinosaurus_ than to
_Baryonyx_, because they share unserrated carinae.

> Troodontidae

Not yet.

> Oviraptoridae

In process by more than one group.

> Therizinosauridae

Not yet.

> ankylosaur families

Forthcoming by Kirkland & Carpenter, and others.

> Pachycephalosauridae

Forthcoming in a paper by Sereno: Systematics, evolution and polar
wanderings of margin-headed dinosaurs (Ornithischia: Marginocephalia). In M.
Benton, E. Kurochkin, M. Shishkin & D. Unwin (eds.), The Age of Dinosaurs in
Russia and Mongolia. Cambridge Univ. Press.

The results, presented in Sereno (1997), are:

Pachycephalosauria
-Stenopelix
-unnamed
--Wannanosaurus
--unnamed (perhaps Goyocephalia Sereno 1986)
---Goyocephlae
---unnamed
----Ornatotholus
----Homalocephale
----unnamed
-----Yaverlandia (!)
-----Pachycephalosauridae
------Stegoceras
------Pachycephalosaurinae
-------Microcephale nov. gen. (et sp.?)
-------unnamed
--------Tylocephale
--------Prenocephale
-------unnamed
--------Stygimoloch
--------Pachycephalosaurus

>Right now I pretty much just have the genera within them listed straight
>out. Does _Irritator_ form a Baryonychinae with _Baryonyx_?

Not according to Kellner.

>Which two oviraptorids form a subfamily? etc.

Good question.

>-Anyone have info on Arkansaurus fridayi?

Being worked on.

>-What about citations for _Archaeopteryx bavarica_

Wellnhofer, P. 1993. Das siebte Exemplar von _Archaeopteryx_ aus den
Solnhofener Schchten.  Archaeopteryx 11: 1-48.

>and _Rebbachisaurus tessonei_?

Calvo, J.O. & L. Salgado. _Rebbachisaurus tessonei_ sp. nov., a new
Sauropoda from the Albian-Cenomanian of Argentina: new evidence on the
origin of the Diplodocidae. Gaia 11: 13-33.

>-Have any studies recently been done on "prosauropods"? Should I be
>showing them as being paraphyletic or is the other view dominant? If they
>are paraphyletic, are there any named clades between Sauropodomorpha and
>Sauropoda?

Sereno (1997) considers them monophyletic.  I remain skeptical.

>-The titanosaur study unfortunately did not include some important genera.
>Anyone have any good ideas about where I can place _Titanosaurus_,
>_Pellegrinisaurus_ and other stuff I have listed as "Titanosauridae
>incertae sedis"?

Good question.

>-Speaking of incertae sedis, there are dozens of genera I have listed as
>"Neotheropoda incertae sedis" that I just *know* can go somewhere more
>specific. I would love for someone to have a look and offer ideas. The
>address is:
>http://www.gl.umbc.edu/~tkeese1/dinosaur/taxa/theropod.htm
>The Tetanurae page could also use some cleaning up in the incertae sedis
>section.

Hey, I'm working on it, I'm workin on it... (326 characters and growing...).

>-Why are the two "sailback sauropods" _Amargasaurus_ and _Rebbachisaurus_
>placed in different families (Dicraeosauridae and Rebbachisauridae,
>respectively)?

See the Calvo & Salgado (1995) paper.

Thomas R. Holtz, Jr.
Vertebrate Paleontologist     Webpage: http://www.geol.umd.edu
Dept. of Geology              Email:th81@umail.umd.edu
University of Maryland        Phone:301-405-4084
College Park, MD  20742       Fax:  301-314-9661