stego time line +

[BPC.APA@email.apa.org (Considine, Blaise)]

Ralph's reference to Regnosaurus northamptoni got me wondering along the 
"who came first" line re stegosaurs. Were the spikey-back types first, 
evolving into the plated types (S. stenops and a Chinese one are the only 
2 I can think of), or was it vice versa? Can some of you provide me with 
a rough time-line for the stegos? (BTW, thanks to those of you who did 
the same re sauropods)

Regarding said plates and spikes (don't flame me, I've deleted all my old 
messages), I don't remember wjhether it's been settled whether the plates 
occurred in parallel rows or a single row, but if they were in a row, 
wouldn't it be likely that the spikes (and where does "thagomizer" come 
from?) would be arranged in the same fashion?

Finally, I vaguely remember reading somewhere that the stegos had 
originally been bipedal and reverted(?) to a 4-legged stance. Is this so?

Ona completely different topic, one of the books my kids checked out from 
the library "Dinosaur Cousins" (not at all scientific; it compares 
dinosaur traits with those of modern animals) said ankylosaurs were 
insectivores. Any truth to that?
Blaise "I'm easily lost in this K/T-impact velocity/extinction debate, so 
I'll lob in a softball type question" Considine 
bpc.apa@email.apa.org