Shunosaurus, Tail Clubs, and Ankylosauria

["Jerry D. Harris" <102354.2222@compuserve.com>]

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Message text written by INTERNET:qilongia@yahoo.com

"Aside from the improbability of a Jurassic ankylosaurid"


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        Um...I think I might have missed something here!  Last I checked,
there were at least two Jurassic ankylosaurids (_Tianchisaurus_ from the
Middle Jurassic of China [1], which reportedly has a tail club, and
_Gargoyleosaurus_ from the Late Jurassic of Wyoming [2]).  Has it since
been shown that the club attributed to _Tianchisaurus_ doesn't belong
there?  If so, and you've got a reference, please let me know!

        Plus, the latest phylogeny of the Ankylosauria [3] looks something
like this (detail omitted; use mono-spaced font):



N   S   P    a
 \   \   \  /
  \   \   \/
   \   \  /
    \   \/ <- node A
     \  /
      \/
      /
     /
    /
   /
  / 

where N = Nodosauridae, S = Shamosaurinae, P = Polacanthinae, A =
Ankylosauridae, and a = traditional "ankylosaurids" (e.g.,
_Euoplocephalus_, _Ankylosaurus_, _Saichania_, etc.)

        Since polacanthines are found in the Late Jurassic (_Mymooropelta_
from the Late Jurassic of Colorado [3, 4]), this means that ankylosaurids
do indeed occur in the Jurassic (although, as far as is currently known,
polacanthines don't have tail clubs -- the ankylosaurian tail club may not
have appeared 'til the Cretaceous if the club attributed to _Tianchisaurus_
isn't ankylosaurian).

[1] Dong, Z.  1993.  An ankylosaur (ornithischian dinosaur) from the Middle
Jurassic of the Junggar Basin, China.  _Vertebrata PalAsiatica_ 31(4): 
257-266.

[2] Carpenter, K., Miles, C., and Cloward, K.  1998.  Skull of a Jurassic
ankylosaur (Dinosauria).  _Nature_ 393:  782-783.

[3] Kirkland, J.I.  1998.  A polacanthine ankylosaur (Ornithischia: 
Dinosauria) from the Early Cretaceous (Barremian) of eastern Utah, pp.
271-281 _in_ Lucas, S.G., Kirkland, J.I., and Estep, J.W. (eds.)  _Lower
and Middle Cretaceous Terrestrial Ecosystems_, New Mexico Museum of Natural
History and Science Bulletin 14.  (don't worry folks; it'll be widely
available in about 3 weeks!)

[4] Kirkland, J.I. and Carpenter, K.  1994.  North America's first
pre-Cretaceous ankylosaur (Dinosauria) from the Upper Jurassic Morrison
Formation of Western Colorado. _Brigham Young University Geology Studies_
40: 25-42.


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                     Jerry D. Harris
                 Fossil Preparation Lab
          New Mexico Museum of Natural History
                   1801 Mountain Rd NW
               Albuquerque  NM  87104-1375
                 Phone:  (505) 899-2809
                  Fax:  (505) 841-2866
               102354.2222@compuserve.com