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Squid Ancestors Emerged in Deep Ocean 100M Years Ago, Japanese Study Finds
Squids originated 100 million years ago and survived the K–Pg extinction by retreating to deep-ocean refuges before rapidly diversifying into coastal species, researchers found.
- Researchers at the Okinawa Institute of Science and Technology published a study in Nature Ecology & Evolution on Monday reconstructing the squid and cuttlefish evolutionary tree, revealing origins around 100 million years ago in deep-ocean habitats.
- Following initial lineage splits in the Cretaceous, squid evolution showed limited branching for tens of millions of years—a 'long fuse' pattern of stability before a sudden explosion of diversity after the mass extinction.
- During the Cretaceous-Paleogene mass extinction 66 million years ago, early cephalopods survived by retreating to deep, oxygen-rich refuges; surface environments were hostile, with ocean acidification likely degrading their internal shells.
- As shallow ecosystems recovered after the extinction, squid and cuttlefish moved into newly available coastal habitats, triggering widespread diversification that explains the vast variety of modern species from giant to pygmy squids.
- Co-Author Daniel Rokhsar stated this evolutionary framework helps link genomic changes to innovations like dynamic camouflage and intelligence, accelerating comparative genomics to study the molecular basis of unique cephalopod traits.
5 Articles
5 Articles
66 Million Years Ago, Squid Survived the Dinosaur-Killing Extinction in Deep-Sea Oxygen Refuges — Then Rapidly Evolved
Learn how a new genomic study reveals that squid and cuttlefish survived a mass extinction in deep-sea refuges before rapidly diversifying into modern species.
Rapid mid-Cretaceous diversification of squid and cuttlefish preceded radiation into coastal niches - Nature Ecology & Evolution
The evolutionary relationships among decapodiform lineages (cuttlefish and diverse types of squid) remain uncertain, with implications for the origin of internalized structures (for example, gladius, cuttlebone and coiled shell) derived from the ancestral chambered shell as well as the ecological shifts between the deep ocean and shallow coastal habitats. To address these questions, we adopted a phylogenomic approach that integrated three new hi…
100 million years ago, an 'evolutionary fuse' was lit in the deep ocean, sparking squid diversification
From color-changing skin to jet-propelled motion, squid and cuttlefish have long fascinated scientists. To understand the origins of their unique characteristics, many attempts have been made to define their evolutionary history. However, the limited fossil record and incomplete genomic information have made it impossible to confidently order the evolution of these enigmatic creatures, until now.
Squid Evolution Ignited 100 Million Years Ago in Deep Ocean, Triggering
Squid and cuttlefish have long captured the imagination of scientists and marine enthusiasts alike with their stunning abilities—from rapid skin color changes to dynamic jet propulsion. Despite decades of research, unraveling their evolutionary history has remained an intricate puzzle. The scarce fossil evidence and
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