Squid Evolution Rewrites Timeline: Rapid Diversification Began 100 Million Years Ago
New research reveals squids underwent a period of rapid diversification much earlier than previously thought, challenging existing theories about their evolutionary history and demonstrating their success wasn’t tied to the Cretaceous-Paleogene extinction event. A novel paleontological approach focusing on fossilized squid beaks – their only hard body part – has uncovered evidence of high squid diversity as far back as 100 million years ago.
For decades,understanding squid evolution has been hampered by their soft bodies,which rarely leave fossil records. This new study, published in Science, bypasses that limitation by analyzing the preserved beaks, allowing scientists to trace the lineage and diversification of these cephalopods. The findings indicate that squids flourished after shedding their external shells, suggesting that the body plan we recognize today was key to their early success. This discovery reframes the narrative of squid evolution, demonstrating it wasn’t a post-extinction recovery story, but a long-term trajectory of adaptation and diversification.Researchers,led by Ikegami et al., developed a method to specifically identify and analyze squid fossils based on their beaks. Their analysis revealed a significant radiation of squid species beginning well before the end-Cretaceous extinction event approximately 66 million years ago. This suggests that the evolutionary pressures driving squid diversification were independant of the mass extinction that wiped out the dinosaurs.
the study underscores the importance of focusing on preservable components when studying soft-bodied organisms and provides a new framework for understanding the evolutionary history of cephalopods – a group that continues to thrive in modern oceans.
