THE lumbering, plant-munching Stegosaurus could swing a mean tail when a voracious Allosaurus tried having it for lunch. Famed for the triangular plates along its back, Stegosaurus also sported nasty, heavy spikes on its tail.
Now palaeontologists say the spikes evolved to whack any sneaky allosaur trying a stealth attack from behind. The tail could swing sideways at up to 8 metres per second, producing enough force to drive one of the spikes through an allosaur鈥檚 skin and into the bone, calculates Frank Sanders of the Denver Museum of Natural History in Colorado. At the Society of Vertebrate Paleontology meeting in Norman, Oklahoma, his team reported an allosaur vertebra with a hole neatly matching a spike.