Plectus parvus

Plectus parvus is a species of nematode (roundworm) found in freshwater and terrestrial environments. It has been sampled in Europe and New Zealand. Along with the similar nematode Panagrolaimus detritophagus, in 2018 it was the first species of multicellular eukaryote to be thawed into a living state after prolonged cryopreservation. Female worms of this species were found in Pleistocene permafrost in the Kolyma River lowland (one of the sites was near the Alazeya River). They were mobile and ate, after being frozen for 30–40 thousand years.