Squids are rarely preserved as fossils because they don’t have hard shells. Their origin and early evolution are the biggest questions in the 500 million-year history of cephalopods, which have been model animals for long-term evolution. Squid beaks, hard mouthparts that have a high fossilization potential, are therefore important clues for studying how squids evolved.

One of the study’s most striking discoveries was how common squids were in ancient oceans. The team found that squid fossils far outnumbered those of ammonites and bony fishes. Ammonites are extinct shelled relatives of squids and have been considered among the most successful swimmers of the Mesozoic era.