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Re: Metatarsal fusion/nonfusion: birds/theropods

Thomas R. Holtz, Jr. wrote:
> At 04:12 PM 3/18/97 GMT+1000, Tim Williams wrote:
> >
> >>  3. All theropod dinosaurs have unfused metatarsals (except Elmisaurids
> >> which do fuse their metatarsals on the proximal end only and CERATOSAURUS,
> >> which does not count here as the type specimen is pathologic).
> >
> >What about the abelisaurids?  I could be way off track here, but
> >don't big'uns like _Carnotaurus_ and _Xenotarsosaurus_ show some
> >degree of fusion of their lower hindlimb elements into a
> >tibiotarsus and/or tarsometatarsus?
> They do have tibiotarsi (or at least some distal fusion of the tibia and
> fibula).  The metatarsus is, alas, unknown for any abelisaurid so far
> described.  Syntarsus, of course, does the same thing with its ankle (hence
> the name...).
> A side note: do any of the newer specimens of Ceratosaurus have metatarsi?
> (A general call to those who have seen the specimens!). If so, do they show
> fusion or not?  I do wonder if the type really is pathological, or if this
> is another case of Pachyrhinosaurus-itis (a weird bony growth found in a
> single specimen may be pathological; one found in ALL the specimens of that
> taxon almost certainly isn't...).
> 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

As I understand it the Fruita specimen of Ceratosaurus has free 
metatarsals. Check with Brooks Britt to be sure.

Jim K.