Tardigrades are a diverse group of microscopic invertebrates widely known for their extreme survival capabilities. Molecular clocks suggest that tardigrades diverged from other panarthropods (arthropods, tardigrades, velvet worms and lobopodians) before the Cambrian period, but their fossil record is extremely sparse. Now, paleontologists have described a new species of tardigrade and redescribed a previously known species, Beorn leggi, both from Canadian Cretaceous-aged amber.
First discovered in 1773, tardigrades are a diverse group of microscopic invertebrates that are best known for their ability to survive extreme conditions.
Also known as water bears or moss piglets, these creatures can live for up to 60 years, and grow to a maximum size of 0.5 mm, best seen under a microscope.
They are able to survive for up to 30 years without food or water, for a few minutes at temperatures as low as minus 272 degrees Celsius or as high as 150 degrees Celsius, and minus 20 degrees Celsius for decades.
Tardigrades withstand pressures from virtually 0 atm in space up to 1,200 atm at the bottom of the Marianas Trench, and are also resistant to radiation levels up to 5,000-6,200 Gy.
They survive by entering a state of suspended animation called biostasis, using proteins that form gels inside of cells and slow down life processes.
“Tardigrades are microscopic invertebrates characterized by a compact body plan with four pairs of typically claw-bearing lobopodous legs that are closely related to onychophorans and euarthropods as members of Panarthropoda,” said Harvard University Ph.D. candidate Marc Mapalo and colleagues.
“Tardigrades are popularly known for the cryptobiotic ability of some species that allow them to survive extreme conditions, such as space vacuum, ionizing radiation, and low subzero temperatures, as well as their worldwide distribution in marine, freshwater, and terrestrial habitats.”
“Despite their ubiquitous nature in the…
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