Sea urchins look like an inanimate bundle of needles, but a closer look at these alien-like creatures reveals a surprisingly complex “all-body brain” that challenges our assumptions about nervous systems, evolution, and the nature of intelligence. The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.

Echinoderms – the phylum of animals that includes starfish , sea cucumbers, sea urchins, and others – are easy to dismiss as “simple” creatures. They might look pretty, but they lack many of the features we typically associate with charismatic creatures and complex intelligence, primarily a centralized brain.

It was previously held that all echinoderms possessed only a rudimentary radial nervous system, little more than an interconnected nerv

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