In early fish-like vertebrates more than 500 million years ago; in a common ancestor of arthropods, such as insects, spiders, and crustaceans, at around the same time; and then in the cephalopod mollusks around 300 million years ago.

在 5 亿多年前的早期类鱼脊椎动物中；节肢动物的共同祖先，如昆虫、蜘蛛和甲壳类动物，大约在同一时期；然后是 3 亿年前的头足类软体动物。