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Re: Ouranosaurus - how many species? Other "spino"-Igaunodontids?


If it wasn't for the odd phylogenetic placement, one could also argue that 
Tenontosaurus fits this category as well. Of course, in this case the 
equivalent of the "spine" takes the form of a much enlarged and relatively 
laterally compressed tail, not a sail/whithers. However, it is likely that what 
ever drove the unique sail/whithers development in other ornithopods and large 
theropods during this period is behind this oddity as well.


-Jonas Weselake-George

On Mon, 26 Oct 2009 16:23:49 -0700 (PDT)
Tim Williams <tijawi@yahoo.com> wrote:

> B tH <soylentgreenistrex@yahoo.com> wrote:
> > Always thought it was kind of weird
> > these guys would appear ... is this the only known genus in
> > the group with spines?
> _Dollodon_, from the Early Cretaceous of Belgium, has them too.  According to 
> Paul (2008): "Neural spines of dorsals, sacrals and caudals form moderately 
> tall sail."  So _Dollodon_ had a sail, but not as tall as that of 
> _Ouranosaurus_.  (The _Dollodon_ holotype [IRSNB 1551] was previously 
> referred to _Iguanodon_.  The taxonomy of 'iguanodonts' is still in a state 
> of flux, including the status of the genus _Dollodon_; so we'll see where 
> IRSNB 1551 ends up.)
> The very large iguanodont _Lanzhousaurus_, from the Early Cretaceous of 
> China, also has rather tall dorsal neural spines - but perhaps not tall 
> enough to support a sail.
> Cheers
> Tim

Jonas Weselake-George <ee555@ncf.ca>