What is the structure not present in early elephants?

It is a common misconception that elephants existed the same time as the dinosaurs did when in fact they have evolved 3 or 5 million years after these creatures.

The tusks of the elephant would probably be the structure not present in early elephants. It is only through evolution that these tusks grew. Some scientists have hypothesized that these tusks develop from the elephants' incisors.