Re: Long-necked stegosaur, head tail mimicry?

[Tim Williams <tijawi@yahoo.com>]

Scott Hartman wrote:

 
> I will point out that specialized low-browsers like
> Nigersaurus and Brachytrachelopan seemed to shed their
> excess neck length quite quickly.  So perhaps a more
> enlightening question would be: Why do they shorten their
> necks, and what does it say about other sauropods who did
> not?


Some titanosaurs had rather short necks - at least by sauropod standards - such 
as _Isisaurus_ and _Mendozasaurus_.  Though the necks were not nearly as 
truncated as found in the very short-necked _Brachytrachelopan_.


Interestingly, _Isisaurus_ was found in the Lameta Formation, which has also 
yielded sauropod coprolites that indicate a diet of grass (Poaceaea) (Prasad et 
al., 2005; Science 310: 1177-1180).  So the shorter necks are consistent with 
low browsing on grass.  Then again, other coprolites have been attributed to 
_Isisaurus_ that indicate a diet that contained leaves (Sharma et al., 2005; 
Micropaleontol. 51: 73-82).  So these titanosaurs may have not specialized on a 
single plant source, with a feeding envelope that included small trees and 
grass.


Speculative, I know...


Cheers

Tim