Number of Stegosaurus stenops plates

[Amado Narvaez <anarvaez@umd5.umd.edu>]

Descriptions of Stegosaurus stenops in many texts state the obvious -- 
that there were four tail spikes -- and elaborate on the possible 
arrangement of the plates (one row or two; paired or alternating) -- but 
I see very little mentioned about how many total plates were on the neck, 
back, hips, and tail (not counting the spikes).

The first restoration by Marsh in 1891 showed only twelve plates. Stephen 
Czerkas in "A Reevaluation of the Plate Arrangement on _Stegosaurus 
stenops_" provides some history on estimates of the number of plates as 
shown in various reconstructions. I think the record was 22 in a Charles 
Gilmore monograph from 1914, but that was to support the paired rows theory.

If I counted correctly, there seem to be 17 plates on the Stegosaurus 
sculpture by Czerkas. I counted the same number in a Franczak painting. 

Is there a best guess about the number of plates based on most recent 
findings? Is there any relationship to the number of plates and the 
number of vertebrae? Could a young Stegosaurus start out with x number 
of plates and then grow more as it matured? 

(The reason I ask is that I'm branching out from illustrating hundreds of 
hands in books for professional magicians to illustrating twelve 
dinosaurs for enthusiastic kindergarteners... and I want the 
illustrations to be as accurate as possible.)

Thanks in advance for any replies!

----- Amado Narvaez
      anarvaez@umd5.umd.edu