PALAEONTOLOGISTS don’t get many chances to name new bones. Evolution uses the same bones over and over again, altering their shape and purpose but preserving their basic nature, so anatomists simply use the same old terms to describe them. A humerus is a humerus, whether it’s in a chicken wing, a walrus flipper, the massive front leg of a brachiosaurus or our own upper arm. A few animals evolve bones that look different enough to earn their own distinct name, like the thagomizer, the fearful-looking cluster of spikes on the end of a stegosaur’s tail.
The name comes from Gary…
