The first bones came in a cardboard box. Nizar Ibrahim, a paleontologist, was in the Moroccan oasis town of Erfoud at the edge of the Sahara, returning from a dinosaur dig in the sands. Inside the box, brought to him by a nomad, were sediment-encrusted pieces more intriguing than anything he had found himself, including a blade-shaped bone with a reddish streak running through the cross section. He took the bones to a university in Casablanca.

That was April 2008.

The next year, he was in Italy visiting colleagues at the Milan Natural History Museum who showed him bones that seemed to be from Spinosaurus aegyptiacus, a strange-looking predatory dinosaur larger than Tyrannosaurus rex that lived in northern Africa about 95 million years ago.

He looked at the spines, part of a giant distinctive sail on the back of Spinosaurus. He saw a familiar red line — possibly a passageway for blood vessels long since decayed away — in the cross section of a bone. “My mind started racing,” he said.

Amazingly, the pieces in Milan and those he had seen a year earlier and 1,200 miles away were from the same ancient skeleton.