Sea stars don’t actually have arms or a body

What is even more intriguing, the ancient fossils give a clue – in the very distant past, the ancestors of starfish had both a body and a head. Or, more correctly, a clear division of the body into several different functional parts. However, the available data are scrappy and only add to the complexity of the mystery. Why, unlike other inhabitants of the planet, sea stars in the course of evolution turned into living heads?