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Re: ORNITHOMIMID THERIZINOSAURS



At 02:46 PM 7/27/98 -0400, Dinogeorge wrote:
>The new Lower Jurassic Lufeng segnosaur jaw, only a few inches long, described
>in the current _Nature_ (July 16) as a therizinosauroid jaw, (1) looks very
>segnosaurian;
        That is good to know. I can't wait to see it (actually, I can and
will wait until the end of the summer when my copy bills are paid off).

>(2) looks somewhat prosauropodan or even ornithischian; and (3)
>does >not< look at all coelurian: ornithomimid, oviraptorid, troodontid,
>dromaeosaurid, tyrannosaurid, maniraptoran, 
        Granted that (temporally) later therizinosaur jaws don't look all
that much like any of these boys either. Of course, this could have
something to do with dietary preference...

>or even theropodan. Unless you think that basal coelurians should have lateral
>shelves on their dentaries
        I'm not sure that therizinosaurs are *basal* coelurosaurs
("coelurians"?) at all. For that matter, it will take some evidence to
convince me that the new specimen is a *basal* therizinosaur, as opposed to
merely representing the FAD of therizinosaurs.

>lateral ridges on their coarsely serrated, leaf-shaped teeth, that is.
        If the specimen is a therizinosaur, then it can be minimally
expected to exhibit those features which are considered characteristic of
therizinosaurs, regardless of taxonomic assignment/phylogenetic position.
Unless I've been leaking data out of my thick skull (quite possible, I am a
student after all...), the shelf and leaf-shaped teeth are also present in
other therizinosaurs. As for the ridges, I am not currently sure. Please do
expand upon this.

        A good question remains: are therizinosaur (ok George, segnosaur)
bones hollow? Do they exhibit any other osteological characteristics
commonly associated with theropods (e.g. very compact lamellar bone)?

        Wagner
----------------------------------------------------------------------------
    Jonathan R. Wagner, Dept. of Geosciences, TTU, Lubbock, TX 79409-1053
                    "...To fight legends." - Kosh Naranek