Euplocephalus (meaning "well-armored head") was a large armored dinosaur, measuring about 20 feet (6 m) long; it weighed about 2 tons. Its wide head had a horny, toothless beak, small, peg-like cheek teeth, bony horns, and a small brain. Among its contemporaries were the large meat-eating "Tyrannosaurus" and "Deinonychus".