Solution to the “Animal Puzzle”: Where is the starfish’s head?

The heads of most animals are easily recognizable, but until this week, scientists couldn’t say the same for sea stars.

Sea stars are animals that belong to… A group of echinoderms, along with sea urchins. common Flat body and five “arms”they are the heroes of marine landscapes, from coastal areas to remote areas of the open sea.

Experts have long tried to understand how sea stars, with their pentagonal body plan, Evolved from an ancestor with double symmetryA common body plan in animals including insects, molluscs, and vertebrates.

“How the different body parts of echinoderms relate to those we see in other groups of animals has been a mystery to scientists for as long as they have been studied,” said study co-author Jeff Thompson. Stady from the University of Southampton, published in the journal nature.

Unlike other animals, which have bodies formed in a bilateral plane, with a left side and a right side, echinoderms have a body divided into five symmetrical segments.

“In their bilateral relatives, the body is divided into the head, trunk and tail. But when looking at a starfish, it is impossible to see how these parts relate to the bodies of bilateral animals,” Thompson explains.

Researchers are studying the secret of the location of the starfish’s head The researchers used genetic and molecular maps of sea stars of this type Patria Miniata To learn about different areas of the body.

In the case of sea stars, They are born from fertilized eggs in the form of larvae that float in sea currents, with a bilateral body shape. As they develop, they end up settling at the bottom of the ocean, at which point they do so They undergo an unusual transformation that turns them into the strange animals they are.

“Our research shows that the body plan of echinoderms evolved in a much more complex way than we previously thought, and that there is still a lot to learn about these interesting creatures,” says Jeff Thompson.Thus, the different parts of the starfish’s “arms” correspond to extensions of its head, with the front part located near the center of the “arms” and the back part near the edges.

In practice, this means that A starfish is a kind of head, without a body, With its mouth facing the ground, its anus facing upward, and five protuberances that help it move.