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Pinacosaurus in AM Novitates


A new issue of American Museum Novitates features some excellent
descriptions of the skull of the primitive ankylosaurid _Pinacosaurus

Hill, R.V., L.M. Witmer & M.A. Norell. 2003. A new specimen of _Pinacosaurus
grangeri_ (Dinosauria: Ornithischia) from the Late Cretaceous of Mongolia:
ontogeny and phylogeny of ankylosaurs.  American Museum Novitates 3395:

The main specimen discussed is a juvenile.  This paper includes CAT scans of
the skull, and some discussion of the various openings in the narial region
of the snout.  The authors recognize _P. grangeri_ and _P. mephistocephalus_
as distinct species; other _Pinacosaurus_ and _Syrmosaurus_ species are
regarded as junior synonyms of _P. grangeri_.

Their phylogeny (skull characters only, darnit!!) finds all anklyosaurs
clustering within a strictly North American Nodosauridae and the more
broadly distributed Anklyosauridae.  "Polacanthids" such as
_Gargoyleosaurus_ and _Gastonia_, as well as _Minmi_, fall out as a
paraphyletic series of basal ankylosaurids rather than a clade.  Sadly,
_Struthiosaurus_ and _Hylaeosaurus_ were not included: it would be
interesting to see if either of these guys is really a nodosaurid, or if
they, too, are basal ankylosaurids.

Online version is at:

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