I think you should try some simple bone plating on the arms/legs. Looking good.

Maybe pump the bones on him? ie rib armour, skeletal claws over his own hands, a spine. Cubone is cute, marowak gets tough, its all lizardy, needs to look much tougher for a 3rd level evolution. Dual clubs (femurs look tough) might be an idea. Good pokemon style achieved

i second cure. it does look pretty rad, though.

if it look to much different it will be a Kangaskhan xD

Doesn't look different enough from Marowak to be a new species, imo