430 million years ago, eurypterids—better known as sea scorpions—had thin, flexible bodies, some also had pinching claws, and could grow up to 3 metres in length. New research hypothesise that they had another weapon at their disposal: a serrated, slashing tail spine.

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430 million years ago, eurypterids—better known as sea scorpions—had thin, flexible bodies, some also had pinching claws, and could grow up to 3 metres in length. New research hypothesise that they had another weapon at their disposal: a serrated, slashing tail spine.