Tracking Cephalopods Through Time

A chart showing the evolution of cephalopods through geologic time.
(Created by Ashley Gallagher for the Ocean Portal)

There are many more species of fossil cephalopods (17,000) than living ones (about 800) and some of the most important groups in the past have no living descendants. While today’s cephalopods are most notable for their many arms and soft bodies, ancient cephalopods are mostly known from their shells because they are well preserved as fossils.