Re: Aussie therizinosaurids?

["Tim Williams" <tijawi@hotmail.com>]

> It said that a characteristic of
> Therizinosaurs is a large, bony crest on the humerus, the deltopectoral
> crest.

Conspicuous by its absence is the lack of a sigmoidal shaft - courtesy of 
the distal "twist", which is quite obvious in the humerus of _Erlikosaurus_. 
 Also in therizinosauroids, the humerus has a pointed internal tuberosity 
on its proximal end.  This cannot be discerned in the Aussie bone.

> So possibly, this is an
> Australian
> Therinosaur and based on relative proportions between the humerus of
> Erlikosaurus and this beast, it was 1,5 times as big as that beast.

Based on the illustration, the humerus could come from a range of theropod 
taxa.

> Not something you want to come across in a dark alley!

I think the biggest danger of encountering a therizinosaur in a dark alley 
would be if it trod on you by mistake.  These large-bodied mega-clawed 
theropods seem to have been ponderous leaf-eaters.

> And with Kakuru being a Avimimid,

I think this goes back to Greg Paul's _Predatory Dinosaurs of the World_, 
and is based on the similar proportions of the respective tibiae.  Like 
_Avimums_, the shin bones of _Kakuru_ were very slender.  I think we'll need 
more _Kakuru_ bones before we can be certain what this theropod was.

> Australia becomes even more
> interesting with this discovery, I hope, with [Ozraptor] being a
> possible ancestor to the the raptors,

According to at least one palaeontologist, _Ozraptor_ is indeterminate and 
the evidence for its inclusion in the Maniraptora is weak.

> the giant Alvarzsaurid Rapator,

This has not been published (AFAIK), but seems to be a safe bet.

> the Euhelopid Rhoetosaurus,

This has been mentioned (or at least alluded to) to in several scientific 
articles.  _Rhoetosaurus_'s referral to the Euhelopodidae is based 
principally on caudal morphology, I believe - especially, the presence of 
forked (or "skid-like") chevrons.  However, considering the doubt 
surrounding the monophyly of Euhelopodidae (sensu Upchurch), the referral of 
_Rhoetosaurus_ to this family (or to Shunosaurinae sensu McIntosh, which 
Upchurch combines with _Euhelopus_ in the Euhelopodidae) is very tentative.  
Those forked chevrons are also found in diplodocids, and apparently pop up 
in a number of sauropod taxa.

> the Titanosaurian "Hughenden Brachiosaurid" (could the new
> partial skeleton be of this critter?) and Austrosaurus,

_Austrosaurus_ might be a titanosauriform - though, again, this placement is 
precarious.

Alas, Australia's only alleged prosauropod (_Agrosaurus_) appears to have 
hailed from Britain, and to belong to _Thecodontosaurus_.  Its Antipodean 
provenance was nothing more than a case of specimen mislabelling.  This 
means that Australia is the only continent not to have documented any 
prosauropod material.  They've even been found in Antarctica.




Tim

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