This group is formerly known as "Hypsilophodontia" and are a collection of agile, bipedal
runner herbivores. Their anatomy was designed for sprinting and jumping, and that would
have been their only defence, except for kicking in extreme situations, like cornerings etc.
"Hypsilophodontids" were normally 1,5-3 metres long, and lived through the Cretaceous.
Thescelosaurus is known to have had scutes along it's back.