Ankylosaur

Ankylosaurs are a group of extinct armored dinosaurs belonging to the taxonomic superfamily Ankylosauria. Their name Ankylosaur means "stiff lizard", and they are often called the armadillos of the dinosaur world because of the bony armor covering their back and head. Many also wielded a club on the end of their tale that would be used as a defensive weapon.

They have been found on every continent except Africa. In 1988 researchers on an expedition to the South Pole discovered a fossilized Ankylosaur It was the first dinosaur ever discovered in Antarctica and was thus named Antarctopelta, meaning 'Antarctic shield'. They had a toothless beak (similar to birds) combined with small teeth on the sides of the mouth and the lower jaw. This indicates they were herbivores that probably fed mainly on tender ground level plants.

Ankylosaurs are found in abundance in the fossil record due to the size and durability of their bones. Most creation scientist interpret the existence of such fossils to mean that the organism was alive at the time of the global flood, which is described in the Biblical book of Genesis. Furthermore because the text says that all land animals were placed on Noah's ark, if correct the dinosaur was also included in their number, and became extinct very recently.

Anatomy
Ankylosaurs are quadrupeds (walk of four legs) with short, powerful limbs and possess the bird-like hips similar to all ornithischians. There are two taxonomic families (Ankylosauridae, Nodosauridae) that are primarily distinguished by the differences in design of the knobs and spikes in their armor. Nodosauridae species have large spikes protruding from their bodies, and narrower heads. They also lacked the bony clubs at the end of their tails possessed by most Ankylosaurids.

Ankylosauridae
Their type genus Ankylosaurus was only about 6 ft tall, but measured between 18-35 ft in length and weighed an estimated 2-5 tons. Its skull was broad and short with a thick armored helmet and cone-shaped horns on the back of its head. Its neck and back were also covered with thick hide and rows of bony lumps and spikes. The bones of its head and back were fused together to increase their strength and shielding capability, and its skin had bony plates embedded within forming scales called osteoderms (or scutes) similar to those possessed by alligators or armadillos. Its most remarkable defensive feature was its tail, which was used as a club and capable of producing sufficient force to break bone during impacts. It was made of ossified (bony) tendons and capped at the end with several large osteoderms.

Polacanthus is somewhat smaller - about 4 ft tall and between 13-18 ft long. But the spikes on its back were much more pronounced, pointing outward on both sides. To date no skull of Polacanthus has been found. The genus that was once placed in the family Nodosauridae due to their lack of tail clubs. More recently, it has been found that they were more closely related to the Ankylosauridae. Opinions still vary about how to place them as they are distinct from other species in the two Families of Ankylosauria. Some suggest that they belong to a subfamily of the Ankylosauridae (Polacanthinae), while others believe they should be assigned their own family Polacanthidae.

Nodosauridae
Nodosauridae is a lesser known Ankylosaur whose name means "node lizard" or "knobbed lizard". Its type genus Nodosaurus was between 13 to 20 feet long and also possessed bony dermal plates covering the top of its body. It may have had spikes along its side as well. Nodosaurids had a club-less tail and it is thought they probably dropped to the ground when threatened so that only its armored back and sides were exposed.