Ankylosaurids

Anatomy

Ankylosaurids are stout, solidly built, armoured dinosaurs. They possess accessory ossifications on cranial bones that cover some skull openings and form wedge-shaped, horn-like structures. Along the ankylosaurid torso are scute rows, which are filled in with smaller ossicles to create a fused shield of armour. Only two collars of armour plates can be found on the neck, as opposed to the sister group, nodosaurids, which have three. Nodosauridae and Ankylosauridae also share the unique attribute of abundant structural fibres in both primary and secondary bone. Ankylosaurids also have an S-shaped narial passage.