The lefts panel shows a generic human paleontologist with a fossil of a Ammonite-species and a painting of Dimetrodon grandis
(best thanks to ~patriatyrannus
! Check out the original work: [link]
On the right panel we see a futuristic Cephalopod with a human skull in his... hand
. He shows an illustration how this common mammal may looked out. The painting right shows the possibly ancestor of this Cephalopod, the so called "Car" which was maybe an armored marine organism.