How would you like to cut off your hand and watch it walk around for years by your side as if nothing had happened? This is clearly the subject of a study carried out in the icy depths of the Atlantic and the Arctic, where researchers observed a type of sea cucumber whose severed foot showed an exceptional capacity for regeneration.
The species in question, Psolus fabricii or Scarlet Psolus, belongs to the dendrochirotid holothurians. With its soft body, covered in scales, and its blood-red tentacles, it already has something to make Lovecraft fans fantasize. Its numerous tubular feet allow it to move on the ocean floor, but this delicate morphology also exposes it to injuries, summarizes an article from the specialized site Refractor.
To understand what happened in the event of major injuries, the researchers took several samples – from amputated limbs, therefore – and observed them for several weeks. They analyzed tissues, anatomical structures and even tracked nutrient absorption using amino acids and ammonia found in seawater.
An independent life
Very quickly, the results surprised the team: instead of deteriorating, a severed foot begins a real repair process. Old and new cells mix, immune cells multiply, and the amputated tissue gradually transforms into a spherical mass of living muscle and connective tissue.
After a month, the wound had become almost indistinguishable from the rest of the sample. The pigmented cells had sunk deeper, leaving a sort of new translucent skin on the surface. The most astonishing thing is that some of these plants continued to survive for years in laboratory aquariums, quietly buried under a layer of sediment.
These limbs did not revert to a complete new animal, but they still lived independently, absorbing nutrients from the soil as if pursuing an existence of their own.
This ability to survive is all the more intriguing as it was observed in an extremely hostile environment. However, it could be that natural seawater, rich in bacteria and organic matter, actually nourished the tissues and promoted their growth. For scientists, this discovery shows to what extent the marine environment can still harbor unknown biological mechanisms.
Other animals are capable of feats of this type: salamanders can regrow their limbs, certain jellyfish manage to rejuvenate by regressing to an earlier life stage, etc. Recently, researchers managed to regrow amputated fingers in mice, paving the way for possible regeneration in mammals… but we will still have to wait a little longer.
