A revolutionary fossil‐digitization technique has uncovered a vast assemblage of squid beaks dating back 100 million years, overturning long-held beliefs about early marine ecosystems.
Hokkaido, Japan—Squids may be the stealthy denizens of today’s oceans, but a groundbreaking study published in Science shows that their ancient ancestors already dominated the seas long before the age of dinosaurs ended. By employing an advanced three-dimensional rock-scanning method, researchers from Hokkaido University have identified 263 fossilized squid specimens—representing around 40 previously unknown species—embedded within Late Cretaceous sedimentary deposits in Japan.
Digitizing the Deep Past
Traditional paleontology relies on painstaking mechanical preparation to reveal fossils, but many delicate remains remain hidden within rock matrices. The Hokkaido University team, led by Associate Professor Yasuhiro Iba, adapted high-resolution computed tomography (CT) scanning to capture every fossil in situ at microscopic scale. This “whole-rock” digitization produces complete 3D models of both the matrix and all buried fossils.
“We effectively turned opaque stones into transparent windows on the past,” explains Iba. “This approach allowed us to detect the tiny, fragile beaks of ancient cephalopods—structures that would have been destroyed by conventional preparation.”
Squid Beaks: Rare but Revealing
Cephalopods like squids lack external shells, making them notoriously underrepresented in the fossil record. However, their chitinous beaks—the hard, dark mouthparts used to tear prey—are far more likely to fossilize. By extracting and digitally sorting through over one thousand beak fragments, the team distinguished two main lineages corresponding to modern shore-dwelling myopsid squids and oceanic oegopsid squids.
- Myopsida: Squids that inhabit coastal waters, often characterized by a single eyelid and adaptations to shallower environments.
- Oegopsida: Deep-sea squids with large eyes and a fully open lens, capable of traversing open-ocean zones.
The simultaneous presence of both groups in 100-million-year-old deposits indicates that the major cephalopod radiations occurred far earlier than previously thought.
The Abundance of Ancient Squids
Analyzing numerical counts and size ranges, the researchers found that cephalopod beaks in the fossil assemblage outnumbered those of ammonites—once thought to be the most successful Mesozoic swimmers—and even surpassed bony fish remains. Some of the largest beaks measured up to several centimeters across, implying body sizes comparable to modern large-bodied squids and even exceeding those of contemporaneous ammonites.
“In both number and size, these ancient squids clearly prevailed in the seas,” says Dr. Shin Ikegami, first author of the study. “Their dominance suggests they were the principal predators and key players in Cretaceous marine food webs.”
Rewriting the Timeline of Cephalopod Evolution
Prior to this discovery, scientists believed that squids only began to flourish following the end-Cretaceous mass extinction 65 million years ago. The new evidence pushes the origin and rapid diversification of major squid lineages back by at least 35 million years.
- Rapid Diversification: The study’s fossil catalog includes at least 40 new species, indicating an “explosive” adaptive radiation during the Late Cretaceous.
- Ecological Pioneers: Squids likely pioneered the evolution of fast, agile swimming and complex neural systems, setting the stage for modern marine predator–prey dynamics.
“These findings change everything we thought we knew about ancient marine ecosystems,” notes Iba. “Squids were not latecomers; they were already thriving apex predators when dinosaurs still ruled the land.”
Implications for Modern Oceans
Understanding the deep evolutionary history of squids sheds light on the resilience and adaptability of cephalopods. Their early success in Cretaceous seas likely underpins their continued ecological prominence today.
- Biomimetic Inspiration: The streamlined body plans and high-performance neuromuscular systems of ancient squids could inspire underwater robotics and naval engineering.
- Climate Resilience: Squids’ ability to colonize both coastal and open-ocean habitats hints at physiological adaptations for variable temperatures and oxygen levels—traits increasingly relevant as oceans warm.
Future Directions: Beyond Beaks
While the fossilized beaks offer vital clues, the Hokkaido team plans to expand the 3D digitization method to explore other microfossils—such as statoliths (balance organs) and muscle attachment scars—that could further illuminate cephalopod soft-tissue anatomy and behavior.
“We’ve only scratched the surface,” says Ikegami. “Next, we hope to reconstruct entire feeding apparatuses and model how these animals hunted, evaded predators, and interacted within their communities.”
A New Window into Deep Time
This study exemplifies how cutting-edge imaging technologies can revolutionize paleontology, transforming opaque rock into data-rich archives. By revealing the hidden diversity and ecological dominance of ancient squids, researchers have rewritten a pivotal chapter in the 500-million-year saga of cephalopods.
“Cephalopods have long been champion model organisms for studying evolution, neural complexity, and behavior,” reflects Iba. “Now, thanks to 3D fossil digitization, we can finally trace their rise to dominance back to the Cretaceous, giving us unprecedented insight into the origins of today’s oceanic titans.”
As technology continues to advance, further discoveries are sure to emerge from beneath the stones—reminding us that even the most fleeting creatures can leave an indelible mark on the story of life on Earth.
