On 31-7-2013 20:21, Cousin Ricky wrote:
> Lystrosaurus and mostrops are both therapsids, which is the line that evolved
> into mammals.  An erect posture would make sense.

Correct. Therapsids they are. Still, if you look at their anatomy, 
Therapsids still have their legs sideways although less so than 
reptiles. The first to develop truly anatomically /modern/ legs were the 
dinosaurs, which contributed to their success.

>
> (Therapsids dominated the mid to late Permian.  I have heard the Permian called
> the "First Age of Mammals.")

Yes, although I disagree with the latter. Mammals only emerged at the 
end of the Triassic. Therapsids have some mammal-like traits but are 
certainly not mammals.

Thomas

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