Starfish have five limbs. Sometimes more. But where should they lay their heads? Researchers are now finally providing an answer. And it’s surprising to say the least!
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The starfish is definitely a very curious sea creature. They have five arms. Sometimes more. But you may be wondering where their heads are. We know that the most advanced scientists have been struggling with this for a long time. But today researchers at Stanford University (USA) finally provide an answer. A much more complicated answer than expected, which they describe in detail in the journal Nature.
The starfish has a head… explodes!
What the researchers knew is that there are genes that are common across all animal groups and code for the tissues that make up different parts of the body. So they ignored the starfish’s unique anatomy and focused on these genes. Using innovative genetic and molecular tools, they mapped the different regions of the funny animal’s body in 3D. And so he discovered that his “head” is not in one place. It is distributed between the center of the starfish and the center of each of its members!
Beyond the “wow” effect, the discovery is of great scientific interest. Because remember that starfish belong to the group of echinoderms. A group to which we are closely related, even if our life cycle and anatomy are very different. Starfish begin their life as fertilized eggs. They swim in the oceans for several weeks – or even months. And then the unthinkable happens. They settle below to go from a bilateral body plan – similar to ours – to a pentaradial body plan – a five-pointed star.
The mystery of the evolution of starfish solved?
Until now, scientists have struggled to explain this development. But the work of researchers at Stanford University opens up possibilities for thought. Because they also show that starfish appear to be completely trunkless. And so they may have evolved from bilateral ancestors. By turning into trunkless heads that crawl at the bottom of the oceans. In a much more complex way than researchers thought.