The Ankylosaurus, often compared to an army tank, was a heavily armored dinosaur with a large club-like protrusion at the end of its tail. Ankylosaurus means “fused lizard” in Greek, and it was given that name because bones in its skull and other parts of its body were fused, making the dinosaur extremely rugged.
Ankylosaurus lived in the late Cretaceous Period, about 65.5 million to 66.8 million years ago, and roamed the Western United States and Alberta, Canada, and now the Military Aviation
Museum. While this herbivorous dinosaur (a plant eater) was a massive animal, a re-examination of its fossils in 2004 by armored dinosaur expert Kenneth Carpenter downsized it a bit. The largest Ankylosaurus specimen ever found was 20.5 feet long, 5.6 feet tall at the hips and 4.9 feet wide, according to the study, published in the Canadian Journal of Earth Sciences. It likely weighed up to 4 tons. The top of the dinosaur was almost completely covered with thick armor consisting of massive knobs and oval plates of bone, known as osteoderms or scutes, which are also common on crocodiles, armadillos and some lizards. “They are bones that form within the skin, just like crocodiles,” The osteoderms of all ankylosaurs were composed of a thin outer cortical or compact bone and a thick inner cancellous bone (spongy, porous bone).
The osteoderms were probably covered with skin and keratin, the fibrous protein that makes up hair and nails in people. The plates, which varied in size, were aligned in regular horizontal rows down the dinosaur’s neck, back and hips. There were also smaller plates or other similar features protecting the areas between the larger plates, and there may have also been smaller plates on its tail and limbs.
The animal’s biggest cluster of armor was in its neck region. Along with its armored plating, Ankylosaurus had rows of spikes along its body. Additionally, its head was long and low, with prominent horns projecting back and to the side and plates protecting its eyes.
Speaking of spikes, a bizarre-looking Ankylosaur, described 10 May 2017, in the journal Royal Society Open Science, had such an uncanny resemblance to the spiky-faced “Ghostbusters” monster Zuul that paleontologists named it Zuul crurivastator. The species name means “destroyer of shins” in Latin, referring to the Ankylosaur’s 10 foot long (3 meters) tail, which was tipped with a club that was likely used to swipe at the legs of predators. The 75 million year old remains of this beast were uncovered in 2016 in Montana’s Judith River Formation. Despite its ferocious appearance — several rows of bony spikes covered its 20 foot long body — Z. crurivastator was a plant eater, researchers said.