Re: Stego plates

[Dinogeorge@aol.com]

In a message dated 96-01-28 16:25:55 EST, longrich@phoenix.Princeton.EDU
(Nicholas R. Longrich) writes:

>       Are there any other stegosaurs besides Stegosaurus (and Diracodon, 
>if we treat that as a separate genus) which have the alternating plates, 
>then? 

We don't have a complete set of plates for any genus except _?Diracodon_, and
that only because of the 1992 find by Bryan Small and Ken Carpenter. What we
do know suggests that the primitive condition is paired, and the derived
condition is alternating. Dong Zhiming notes alternating plates for
_Wuerhosaurus_ and _Monkonosaurus_, but we only have a couple of plates from
either genus, so the basis for his assertion is unclear. But for now I take
it at face value.

So--for _?Diracodon stenops_, the condition is alternating for sure.

For _Stegosaurus armatus_, _ungulatus_, etc., it's alternating probably.

For _Wuerhosaurus_ and _Monkonosaurus_, it's alternating possibly.

For all other genera (if memory serves me here), it's paired probably.