Found it!

Mitch was examining the tooth in front of him. It was a large tooth that certainly belonged to the lower jaw, probably one of the incisors, one of those used to tear flesh and in fact were continually lost and replaced. He and his companions had found plenty of them since they'd entered the forest. Not just teeth, but also scales, footprints, marks on trees, everything; that spinosaurus had left several traces behind it.

Such finds, although they might seem small, were actually extraordinary. With them he and Max had been able to examine the animal's DNA, discovering that it had many genetic traits in common with the spinosaurs. It was clear that it had evolved from them.