''Plectus parvus'' is a species of nematode ( roundworm) found in

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...

and terrestrial environments. It has been sampled in Europe and New Zealand. Along with the similar nematode ''

Panagrolaimus detritophagus ''Panagrolaimus detritophagus'' is a terrestrial free-living nematode (roundworm). It has been reported in California, South America and Europe. It is the type species of the genus '' Panagrolaimus''. In 2018, it, along with another nematode spe ...

'', 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 Permafrost is ground that continuously remains below 0 °C (32 °F) for two or more years, located on land or under the ocean. Most common in the Northern Hemisphere, around 15% of the Northern Hemisphere or 11% of the global surface ...

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.

Taxonomy

''Plectus parvus'' was described by the English zoologist

Henry Charlton Bastian Henry Charlton Bastian (26 April 1837 in Truro, Cornwall, England – 17 November 1915 in Chesham Bois, Buckinghamshire) was an English physiologist and neurologist. Biography Bastian was born at Truro, Cornwall and graduated from University ...

in 1865. The names ''Plectus potamogeti'' (Schneider, 1937) and ''Rhabdolaimus baltonicus'' (Daaday, 1894) are considered synonyms. Sources differ on its higher level taxonomy. The World Register of Marine Species places it in order Plectida, while the Integrated Taxonomic Information System places it in the order

Araeolaimida Araeolaimida is an order of marine free living nematodes. References Araeolaimidaat WoRMS Nematode orders {{chromadorea-stub ...

Anatomy

Adults of this species are reported to grow to 0.4–0.6 mm long. They possess two alae. The body is defended by a thin cuticle. The males possess asymmetrical

spicules Spicules are any of various small needle-like anatomical structures occurring in organisms Spicule may also refer to: *Spicule (sponge), small skeletal elements of sea sponges *Spicule (nematode), reproductive structures found in male nematodes ( ...

Ecology

In the river sediments and soils it inhabits, this worm is part of the

benthos Benthos (), also known as benthon, is the community of organisms that live on, in, or near the bottom of a sea, river, lake, or stream, also known as the benthic zone. It has been shown that interaction between this species and another soil nematode ''

Bursilla monhysteria ''Mesorhabditis'' is a genus of nematodes. Species in the genus ''Mesorhabditis'' exhibit an unusual form of parthenogenesis Parthenogenesis (; from the Greek grc, παρθένος, translit=parthénos, lit=virgin, label=none + grc, γ� ...

'' in damp podzols increases both bacterial biomass and nitrogen mineralisation. It is one of the nematodes present in estuarine mud, and because of the absence of quantifiable levels of

megafauna In terrestrial zoology, the megafauna (from Greek μέγας ''megas'' "large" and New Latin ''fauna'' "animal life") comprises the large or giant animals of an area, habitat, or geological period, extinct and/or extant. The most common threshold ...

present in more polluted sediments, these nematodes can be used to assess pollution levels.

References

{{Taxonbar, from=Q4134395 Chromadorea Animals described in 1865