Has anyone answered the question “What are starfish?” An even bigger mystery has been found

If we wanted to describe a starfish, we might start by saying that it is an animal with five arms radiating from its center like the points of a star. We would be wrong. The limbs have nothing to do with the limbs of other animals. These limbs are the animal’s head.

Don’t lose your head. The reason is simple: starfish They’re just that, bosses Moving along the sea floor, they are heads that, at some stage of development, have begun to dispense with the rest of the body.

Echinoderms. This can be applied to starfish and their closest relatives (such as sea urchins, sea cucumbers or sea lilies), which together form the phylum Echinodermata (Echinoderms). Echinoderms belong to the branch Bilateria, whose distinctive feature is the bilateral symmetry that characterizes the vast majority of animals on our planet.

But echinoderms abandoned this bilateral symmetry to become animals with radial symmetry. Or almost, if we consider that echinoderm larvae present this form of bilateral symmetry characteristic of the rest of this taxonomic group.

Searching among genes. Now, thanks to a genetic study of these animals, a team of scientists has discovered a strange fact when analyzing the reason for this change in the symmetry of this group of animals, which is that it is the absence of a body that turns them into heads. Walking

He did this by studying a particular type of star, namely… Patria Miniata. They manipulated the genes of the stars to see which genes were expressed in the cells and parts of the anatomy of these animals.

They first took samples from each section of these animals to build a “3D model of mRNA throughout the body.” Explain to Live sciences Laurent Formaire, one of the study’s authors. They then used a fluorescent dye that they attached to different types of messenger RNA in order to determine their expression in different regions of the star’s body. Those responsible for the study published their work in article In the magazine nature.

Walking on the lips. Thus, they were able to ignore some of the prevailing hypotheses about the strange evolution of these animals, and found strange details about the anatomical structure of these animals. Based on this finding, biologist Thurston LaCalle He pointed out To the starfish as a disembodied head that “walks on its lips.”

These animals use organs originally intended to manipulate the animal’s food to move. This is not the only uniqueness of the animal that is capable of this Take out one of your stomachs outside its body to digest difficult prey.

The whims of evolution. Researchers aren’t sure what evolutionary quirk led these animals millions of years ago to dispense with everything but their heads. The evolution of echinoderms as an independent clade occurred during the Cambrian.

This Paleozoic era is characterized by a diversity of animal forms unimaginable today, most of which are lost today, and many of which we know are shrouded in absolute mystery. This discovery may help us learn more about the early evolution of animals, but it may raise more questions than answers to the study of evolution on Earth.

In Chataka |

Image | Jerry Kirkhardt, CC by 2.0 Bond