The Astonishing Discovery: Starfish Are Just Giant Heads

Where is the head of a starfish?

Zoologists have finally found the answer to this centuries-old question. A new study published in the journal Nature reveals that starfish aren’t just in possession of a head — they are a head. This means that their so-called “arms” are actually heads as well. It turns out that starfish have a very minimalistic body, as they lack a trunk or torso.

Understanding Echinoderms

This remarkable finding may revolutionize our understanding of echinoderms, a group of creatures that includes sea cucumbers and sea urchins. Echinoderms, with their peculiar bodies and mysterious evolution, have puzzled scientists for a long time. While most animals exhibit bilateral symmetry, starfish and other echinoderms have radial symmetry, resembling a flower. This makes it challenging to comprehend their bodily functions. One peculiar aspect is that starfish are not born with this form. They undergo metamorphosis to achieve their unique shape. They begin as fertilized eggs and become free-floating larvae, similar to plankton. After a few weeks, they settle on the ocean floor and astonishingly transform from a bilateral body plan to a pentaradial one, with five points.

Cracking the Genetic Code

Despite our apparent lack of resemblance to starfish, genetics tell a different story. Through RNA tomography, the researchers created a 3D map of gene expression in starfish. They focused on genes associated with the starfish’s ectoderm, which includes the nervous system and skin, labeling these genes with fluorescent dyes. The study revealed that genes responsible for head development are active throughout the starfish, even in the arms. On the other hand, genes related to the trunk or torso are hardly expressed. The researchers concluded that this suggests a significant decoupling of the head and trunk regions in echinoderms, particularly starfish. In terms of evolution, this discovery raises many new questions. The fossil record indicates that echinoderms’ ancestors seemingly had a trunk. Therefore, this new understanding of starfish morphology invites further exploration and research into the evolution of echinoderms.

Astonishing Implications

The revelation that starfish are essentially giant heads crawling across the seafloor is a groundbreaking development. It challenges the assumptions that have been held for centuries about these intriguing creatures. Moreover, it opens up a world of possibilities for studying and understanding the evolution and biology of echinoderms as a whole.

Conclusion

The new research on starfish, published in Nature, reveals a surprising truth: they are heads without a real body. This discovery has shed light on the unusual morphology and evolution of echinoderms, prompting further questions and investigations into these enigmatic sea creatures.

Source: Oh God… Those Aren’t “Arms” on Starfish, Scientists Say