Re: Therizinosauroid apomorphies

["Mickey Mortimer" <mickey_mortimer@email.msn.com>]

Good list Nick, but I have a few observations-

> -dorsoventrally expanded, laterally directed anterior iliac blade
> (nanshiungosaurus, segnosaurus)

absent in Beipiaosaurus

> -edentulous dentary tip (Erlikosaurus, Segnosaurus)

absent in Alxasaurus (I'm unsure of the condition in Beipiaosaurus)

> -prominent rugosity just dorsal to the posterior tip of the iliac
> blade (Segnosaurus, Alxasaurus)

not evident in Beipiaosaurus

> I seem to recall that there is a partial skull for Segnosaurus, showing
the
> same inflated basisphenoid of Erlikosaurus.

Unless this is unpublished, I believe you're mistaken.  If you have the
reference though, I'd love to hear about it.

> So even if the apomorphy list isn't overwhelming by itself due to
> its spottiness, the rest of the anatomy is shoving them into Maniraptora
> and in particular towards Oviraptorosauria- largely confined to the same
> branch of the tree, they pretty much have nowhere to go except with each
> other. At least that is how I interpret it.

I completely agree.  Despite the fragmentary nature of Beipiaosaurus, the
therizinosaurs are obviously monophyletic.

Mickey Mortimer