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Re: _Bienosaurus_ questions

Mike Keesey (tmk@dinosauricon.com) wrote:

 1) _Bienosaurus_ does not belong in Ankylosauria.
 2) _Bienosaurus_ belongs in Scelidosauridae.
 3) Scelidosauridae belongs in Ankylosauria.>

  Dong's reasoning is this:

  All thyreophores or whatever that are not strictly ankylosaurs or
stegosaurs are scelidosaurids ... his Scelidosauridae is effectively
a wastebasket group.

  However, based on what I've seen, *Bienosaurus* is a very partial
specimen that has few autapomorphies and may be a few things, but not
complete enough to be really comparable to *Scelidosaurus*. It
certainly looks ankylosaurian, however the jaw is also similar to
*Scelidosaurus* intrinsically, but this same goes for other animals,
including *Emausaurus* (Xu, Wang, & You, and Carpenter, all agree on
the more basal nature of this taxon to *Scelidosaurus* without
contrary data).

  It is clear that the teeth are more dervied than *Scelidosaurus* in
having a complete cingulum on the crowns, and crowns which are
mesiodistally longer than in *Scelidosaurus* ... this gives
*Bienosaurus* more ankylosaurian characteristics than any other
"anklylosaur" or "scelidosaur." Scelidosauridae is best defined as
{*Scelidosaurus* <= *Ankylosaurus*, *Stegosaurus*} to avoid the
wastebasket setup Dong provides.

Jaime A. Headden

  Where the Wind Comes Sweeping Down the Pampas!!!!

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