RE: the last stegosaur

["Tim Donovan" <msdonovan66@hotmail.com>]

> From: "Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>
> To: <msdonovan66@hotmail.com>, <dinosaur@usc.edu>
> Subject: RE: the last stegosaur
> Date: Mon, 29 Jul 2002 09:32:21 -0400
>
> > From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> > Tim Donovan
> >
> > Which stegosaur was the youngest? Wuerhosaurus was of
> > Tsagantsabian age, and
> > may have been pre-Barremian. I notice stegosaurs were not included in 
> the
> > faunal list for the Mazongshan unit of Barremian age. But
> > Katsuyamakensaurus is supposedly of Barremian-Aptian age.  Is
> > that cerdible?
>
> Given that no material has yet to be published, described, and even (as far
> as I can remember) even photographed and put on the web concerning the
> informal taxon "Katsuyamenryu" (aka "Katsuyamekensaurus"), it has
> (currently) unverifiable credibility...  Furthermore, if (for example) this
> was based soley on teeth, or on isolated conical plates, it could very well
> be something other than a stegosaur.
>
> Ah, the joys of using the web as a primary resource... :-S
>
> >   Wuerhosaurus was once considered as young as Albian. I also note
> > stegosaurs seem extirpated by the Barremian in America.
>
> In answer to your question, though, Wuerhosaurus was once considered to be
> the latest-occuring stegosaur, but new (as you note) new data indicate that
> it could be older than the Wealden stegosaur material.

   But is Wealden stegosaur material e.g. the Craterosaurus fragment, 
reworked? Also is the age of the Wealden well known? Is it Hauterivian or 
could it range frm Berriasian to Barremian?




 The Katsuya material
> may, or may not, be stegosaur, but (as with its morphology) its 
> stratigraphy
> is not yet published. (Early Cretaceous units in Japan represent quite a 
> big
> chunk of time).
>
> So (depending on the precise age of Wuerhosaurus), either that Asian form 
> or
> the Wealden taxa  or the problematic (age and morphology) Monokosaurus of
> Tibet or various possibly stegosaurian trackways may be the youngest known
> indication of Stegosauria.


  I once read that the unit that yielded Malawisaurus also yielded 
stegosaur material. When I asked about the age of this unit, somebody 
mentioned 115 Ma, if he remembred what Jacobs told him correctly. 115 Ma 
would be much younger than Paranthodon or any other definite stegosaur.





>             Thomas R. Holtz, Jr.
>                 Vertebrate Paleontologist
> Department of Geology           Director, Earth, Life & Time Program
> University of Maryland          College Park Scholars
>                 College Park, MD  20742
> http://www.geol.umd.edu/~tholtz/tholtz.htm
> http://www.geol.umd.edu/~jmerck/eltsite
> Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
> Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796




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