Stegosaurs started as basal thyerophores with enlarged scutes along the back
and spines on the tail, and evolved into forms with plates on the back, and long
spikes along the tail (Stegosauridae), and in (Stegosaurinae) the plates on the back
had moved all way down the tail, leaving only 4 - 8 spikes left, for defence. There was
allso a large spike jutting out from each shoulderblade, and the thout was covered
in small ossicles. Kentrosaurus was a rather small species, only 5 metres long,
while the huge Stegosaurus was the double size. They lived through the late
Jurassic, in North-America, Asia and Africa.
