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The sea spider can regrow an entire body part, not just a single lost limb. This is shown by a study from the Humboldt University in Berlin that may help people in the future.
– Nobody expected this. We are the first to show that it is possible, says researcher Gerhard Scholtz, who led the study in Germany.
It is well documented that many types of arthropods such as centipedes, spiders and other insects can grow a new limb after losing it.
– Crabs can even automatically discard limbs if attacked. They replace the limb with a new one, says Scholtz.
Sea spiders have a very small body and some of the organs therefore go out into the long legs, which vary in number depending on the species.
What the researchers discovered is unique about the small eight-legged sea spider used in the study is that the animal can grow other body parts than just limbs.
New rear grew out
The researchers amputated parts of the back and front bodies of 23 animals, including adults and juveniles, and studied the results. In the adult spiders, the body parts did not grow, but in the young specimens there was a total or almost total regrowth. Among the parts that were recreated were the rectum, anus, musculature and parts of the genitals.
Ninety percent of the spiders in the study survived in the long run. Some of the older animals were alive two years after the study.
The researchers are now interested in which mechanisms on a cellular and molecular level govern the regrowth of body parts.
The ability varies across the animal kingdom: for example, flatworms can regenerate their bodies from a few single cells. Vertebrates, to which man belongs, practically lack the ability. The exception is some lizards that can grow a lost tail.
Can help people
– Perhaps stem cells are involved, cells that are undefined and can assume new forms and functions, says Scholtz.
The mechanism that controls the regrowth of body parts in arthropods may be useful in medical treatments for humans in the future, for example when a patient loses a finger.
– At least we hope so, says Scholtz.
The study has been published in the scientific journal PNAS.
Facts
Sea spiders
Sea spiders live at all depths in the oceans. There are about 15 species in Swedish waters, hundreds in the world. Modern sea spiders belong to the order Pantoʹpoda.
The animals superficially resemble spiders, although they are arthropods. The body size varies between 1 millimeter and 10 centimeters. In one genus, the span of the legs can reach 70 centimeters.
The mouth sits at one end of a proboscis. As a rule, the spider has four, in some species five or six pairs of walking legs. Because the body is so small, some organs go out in the legs, and special respiratory organs are missing.
The male carries the clumped eggs on his ovipositors.
Facts: The National Encyclopedia.
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