“At first glance, nematodes are unassuming roundworms—but don’t underestimate them.
In 2018 scientists announced they had discovered and revived two types of microscopic nematodes found in the Siberian permafrost, estimating they may have been 42,000 years old. Now these roundworms are the subject of more research, which posits that one of these nematode varieties represents a new species, dubbed Panagrolaimus kolymaensis for the Kolyma River where they were found. The new research, published on July 27 in the journal PLOS Genetics, also compares the Siberian worm’s survival mechanism with one found in another nematode species, Caenorhabditis elegans—a model organism used in laboratories around the world. The researchers further claim that the P. kolymaensis worms are actually 46,000 years old, based on their dating of plant matter found with these nematodes.
“The radiocarbon dating is absolutely precise, and we now know that they really survived 46,000 years,” says study co-author Teymuras Kurzchalia, a cell biologist emeritus at the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden.
Panagrolaimus species are found around the world and are known for surviving in environments that regularly expose them to desiccation or freezing, says Ann Burnell, an emeritus professor of biology at Maynooth University in Ireland, who was not involved in the new study.
If the worms really are as old as the study suggests, they would be by far the most stunning examples of what scientists call cryptobiosis—an organism’s ability to suspend its own metabolism in poor conditions.”

https://www.scientificamerican.com/article/46-000-year-old-worm-possibly-revived-from-siberian-permafrost/#:~:text=At%20first%20glance%2C%20nematodes%20are,have%20been%2042%2C000%20years%20old.