Re: Estimating Hip Heights

[Tim Williams <tijawi@yahoo.com>]

Jaime Headden <qi_leong@hotmail.com> wrote:

> Senter, P & Robins, H. J. 2010. Hip heights of the
> gigantic theropod dinosaurs *Deinocheirus mirificus* and
> *Therizinosaurus cheloniformis,* and implications for museum
> mounting and paleoecology. _Bulletin of th Gunma museum of
> Natural History_ 14:1-10.
>   available online at: 
> http://www.gmnh.pref.gunma.jp/research/no_14/bulletin14_1.pdf


Thanks for the paper alert Jaime.

As Senter and Robins makes clear, both _Deinocheirus_ and _Therizinosaurus_ 
would have been taller than the largest Mongolian tyrannosaurs.  So large body 
size was one defense against predators.  The other defense was the big and 
heavy manual claws.  As both _Deinocheirus_ and _Therizinosaurus_ have been 
regarded as herbivores, it seems to me that the long forelimbs were principally 
retained as defensive weapons.  It's difficult to envision what use the claws 
were in foraging 

Not mentioned is the uber-oviraptorid _Gigantoraptor_, from Inner Mongolia.  
_Gigantoraptor_ had a hip height of 3.5m (Xu et al., 2007), which is in the 
same ballpark as the estimates for _Deinocheirus_ (3.5 m) and _Therizinosaurus_ 
(3.0).

_Gigantoraptor_ seems to have been quite cursorial for its size, possibly 
allowing it to flee an approaching predator.  This would not have been an 
option for _Therizinosaurus_ (assuming it had typical therizinosaur-like 
proportions, which seems a safe assumption).  As for _Deinocheirus_ - it all 
depends on how ornithomimid-like the rest of the postcranium was.  And as Jaime 
noted, ornithomimosaur affinities for _Deinocheirus_ have been questioned. 


Cheers

Tim