Re: Megalosaurus bucklandii

[Thomas_R_HOLTZ@umail.umd.edu (th81)]

>   What is the current opinion on the classification of _Megalosaurus 
>bucklandii_.  I know Greg Paul related it to _Torvosaurus_ and 
>_Poekilopleuron_; but as I was looking through _The Dinosauria_, I 
>noticed that the type material consists only of a dentary.  How sure are 
>we that the referred postcranial material belongs to _M. bucklandii_?  Is 
>it possible that the postcranial material belongs instead to a 
>torvosaurid or eustreptospondylid, and that _Megalosaurus_ itself is neither?

A British graduate student is re-examining the Stonesfield Quarry theropods
and other British material referred to Megalosaurus.  I can report that she
has found the M. bucklandi IS a real taxon.

There is more material than just the dentary.  With nonarticulated bones, it
is common to pick one as the type, even if it is fairly certain that other
bones nearby are the same animal.

In my opinion, it is the same critter as Poekilopleuron, and closely related
to Torvosaurus (although I disagree with Greg Paul on the synonym of the two).

In the latest round of phylogenetic analyses, I found that Megalosaurus and
Torvosaurus form a monophyletic Megalosauridae, the sister taxon to
Spinosauridae.  These two families are nested within a weakly supported
"Megalosauroidea" (aka Torvosauroidea aka Spinosauroidea), along with
Piatnitzkysaurus, Eustreptospondylus, and Afrovenator.

Thomas R. Holtz, Jr.
Vertebrate Paleontologist
Dept. of Geology
University of Maryland
College Park, MD  20742
Email:Thomas_R_HOLTZ@umail.umd.edu (th81)
Fax: 301-314-9661
Phone:301-405-4084