Until it was moved to make room for a Tyrannosaurus skull replica a few weeks ago, a stilt-legged mammal skeleton stood behind me during my weekly sessions cleaning a fossil crocodile at the New Jersey State Museum. Almost every visitor who stopped to comment on the skeleton had a different idea about what it might be. Some were convinced that it was a moose – what other animal had such broad antlers? – while others suspected that the animal was an elk or deer. A few were completely baffled by the creature’s osteological architecture. Missing the enveloping layers of flesh and fur, the skeleton was an enigma.

I would have been shocked if a visitor walked up to the ancient skeleton