Researchers from Unity College in Maine have discovered a new species of tardigrade on Allen Island, off the coast of Maine. The study was published in the Proceedings of the Biological Society of Washington. More than 1,000 species of tardigrade, which are often called water bears or moss piglets, have been discovered so far, but this new species sports some unusual features.
Tardigrades are fascinating aquatic micro-animals, able to survive in the harshest habitats. They have been discovered in hot springs, under glaciers and at the bottom of the ocean. They are not extremophilic, so they don’t thrive in extreme environments, but they can withstand doses of radiation a hundred times higher than the human lethal level, temperatures between absolute zero and above the boiling point of water, and pressures six times greater than what is found at the bottom of the Mariana trench – the deepest part of the world's oceans.
Tardigrades can also survive in space. Two species were tested in low Earth orbit, where they were exposed to extreme temperature changes, a near vacuum and high levels of radiation. The species in the study went without food, water, and oxygen for the duration of the mission. Once back on Earth, scientists deposited them in a few drops of water and the tardigrades returned to their normal state like nothing had happened.
The new species was discovered on the surface of acorn barnacles (Semibalanus balanoides), found across North America and northwestern Europe. The species is called Echiniscoides wyethi, after the American artist Andrew Wyeth and his family who own Allen Island. It has an average length of 1 millimeter (0.04 inches) and four pairs of legs, with a variable number of claws (between 7-10) on the first, second and third pair, an unusual feature for tardigrades, but always 7 claws on the last pair.
This tardigrade also differs from other species in that it has a much longer and more flexible buccal tube, which has a similar function to the human esophagus.
Tardigrades are studied for their resilience to change as well as being used as bio-indicators, for example for pollution levels, since they proliferate in such a variety of habitats. Scientists believe that understanding tardigrades' remarkable hardiness could lead to the development of techniques to protect other organisms, including humans, to sudden changes in the environment.