IDENTITY OF BECKLESPINAX

[darren.naish@port.ac.uk]

Truett Garner wrties...

> I was looking for some information in ' the Dinosauria ' when I came 
> upon an illustration of the dorsals assigned to Becklespinax 
> altispinax . Has anyone compared these dorsals to A.atokensis or 
> B.walkeri ? The time frame (Barremian) fits B.walkeri, but could 
> also fit an ancestor of A.atokensis .

I'm reviewing the Wealden Group theropods for my M. Phil. 
dissertation and am working on _Becklespinax_ and other forms at the 
moment (though I am more concerned with the taxonomy and anatomy of 
the smaller forms - will be posting details when the work nears 
completion) . _Becklespinax_ was of course regarded as a species of 
_Acrocanthosaurus_ by Greg Paul (1988), but in fact differences are 
pronounced and this referral has not been accepted. Vertebrae of the 
two genera differ markedly in the orientation of their transverse 
processes, as well as other, more detailed features.

The _Becklespinax_ vertebrae have also previously been 
compared to _Baryonyx_ by both Charig and Milner (1990) and Kellner 
and Campos (1996), but as is clear from Charig and Milner's (1997) 
monographic description of _Baryonyx_, the _Becklespinax_ vertebrae 
are clearly not referrable to this taxon. Not only do they differ in 
morphology, they are also (as George Olshevsky has noted many times) 
from different parts of the Wealden. 

There are two possible identities for _Becklespinax_ that really need 
testing: (1) that it is a carcharodontosaurid perhaps related to 
_Acrocanthosaurus_, and (2) that is related to _Piatnitzkysaurus_. 
The latter is George Olshevsky's idea, and though I understand he 
has/had plans to publish a paper on this taxon, the idea has not 
been published. George, would you care to comment?

DARREN NAISH
darren.naish@port.ac.uk