Squid Genomes Reveal Deep-Sea Refuges Enabled Survival Through Mass Extinctions

Newly sequenced cephalopod genomes paired with global datasets indicate squid and cuttlefish originated in deep ocean environments more than 100 million years ago. Researchers conclude these lineages weathered mass extinction events by sheltering in oxygen-rich deep-sea zones while surface ecosystems collapsed.

Evolutionary change remained minimal for an extended stretch, then accelerated sharply once post-extinction conditions opened up shallow-water niches. The expansion into those habitats triggered rapid diversification, producing the morphological and behavioral range seen in modern cephalopods.

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