Research reveals squids dominated oceans 100 million years ago

By Stephen Beech

Ancient squids dominated the oceans 100 million years ago, reveals new research.

A state-of-the-art fossil discovery technique shows that squids originated and quickly rose to become dominant predators in the Earth's seas tens of millions of years ago.

The new findings reshape our understanding of ancient marine ecosystems, say Japanese scientists.

Researchers from Hokkaido University developed an advanced fossil discovery technique that completely digitizes rocks with all embedded fossils in 3D form.

It allowed them to identify 1,000 fossilized cephalopod beaks hidden inside Late Cretaceous rocks from Japan.

Among the small and fragile beaks were 263 squid specimens, including about 40 different species that had never been seen before.

The researchers explained that 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.

The researchers say squid beaks - hard mouthparts that have a high fossilisation potential - are important clues for studying how squids evolved.

One of the most striking discoveries of the study, published in the journal Science, was how common squids were in ancient oceans.

The researchers 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.

Study first author Dr. Shin Ikegami said: “In both number and size, these ancient squids clearly prevailed the seas.

“Their body sizes were as large as fish and even bigger than the ammonites we found alongside them.

"This shows us that squids were thriving as the most abundant swimmers in the ancient ocean.”

The research also revealed that the two main groups of modern squids, Myopsida, which live near the shore, and Oegopsida, found in the open sea, were already present around 100 million years ago.

Until now, scientists believed that squids only began to flourish after the mass extinction event that ended the age of dinosaurs around 65 million years ago.

The new study shows that squids had already originated and explosively diversified long before then.

Study leader Professor Yasuhiro Iba said: “These findings change everything we thought we knew about marine ecosystems in the past."

He added, “Squids were probably the pioneers of fast and intelligent swimmers that dominate the modern ocean.”