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Much better link. Some footnotes: Sadly the genus is not new (That would made the case much more simple). There are at least 39 extant species of Panagrolaimus

Much better link. Some footnotes: Sadly the genus is not new (That would made the case much more simple). There are at least 39 extant species of Panagrolaimus (Rhabditida, fam. Panagrolaimidae) know yet. So we aren't talking about an isolated, last-of-their-kind, live fossil. Also not exclusive from permafrost. Relatives of this species had been found in China, USA, South Spain, Iran, Peru or India. They move fast and are very active. They aren't parasites, and feed on bacteria and microorganisms So they live in soils with decaying organic matter. A species is common in agricultural soils in California; other is often found in dead flower heads of ornamental Asteraceae (=family of the sunflower) like Chrysanthemum or Zinnia. There is a third associated with leaf litter and bark beetles in Utah, and a Peruvian species appeared in exported rotten ginger rhizomes. So we are talking about a kind of nematodes closely (but not exclusively) associated with agricultural practices, sometimes in temperate or Mediterranean climates Well. The scenery does not suggest endemic Siberian fauna, or points directly towards -46000 years ago, but neither discard it anyways. I still think that the proofs that an animal lived for 46000 years (much more than corals?) are circumstantial at most, and shouldn't be taken as definitive

pvaldes 3y ago
The closer known relatives of this worms add more context. Some species of Panagrolaimus were moved later to the genus Propanagrolaimus comprising freshwater aquatic species. Three species inhabit tropical rivers in India and had been found associated to dead roots of Lotus The roundworms were found at 40m deep, but this is not moon-distance level. I can totally imagine as plausible the scenery of an aquatic roundworm living among water lilies roots in the muddy bottom of a 35m deep Siberian lake and then going the extra mile down to reach buried yummy decay. This animals don't live in the surface necessarily. I could see also the animal also being dragged or swimming down a partially thawed 5 milimeters wide crevice attracted by buried decay without contaminating it. Other close relative genus live in the bark of big tropical trees in Iran. We had seen a lot of videos of tall conifers falling lately when the permafrost gets unstable in warm weather. Falling trees can inject seeds or animals deeply in a muddy soil. I can imagine an 80m tall pine with worms in its bark falling, stabbing the permafrost, and then sinking by its own weight a little more each spring until laying at 40m deep. I don't thing that would need 46000 years to this organic matter to disappear completely while it feeds the microorganisms that would in turn feed thousands of generations of roundworms. So yes, the decay could be prehistoric, but the worms could be still much more modern. The main difference in that cases is that the article would be more difficult to sell. Would end published in a more specialized, perfectly legit and decent, but lower rank journal. Free-living roundworms aren't rare, most of them are simply ignored. The number of people in the planet able to navigate the taxonomy of the zillion species alive could be counted in the tens or thousands probably. I had a lot of headaches dealing just with the parasitic of vertebrate marine animals, and this is just a tiny fraction of the total.

pvaldes 3y ago

The closer known relatives of this worms add more context. Some species of Panagrolaimus were moved later to the genus Propanagrolaimus comprising freshwater aquatic species. Three species inhabit tropical rivers in India and had been found associated to dead roots of Lotus The roundworms were found at 40m deep, but this is not moon-distance level. I can totally imagine as plausible the scenery of an aquatic roundworm living among water lilies roots in the muddy bottom of a 35m deep Siberian lake and then going the extra mile down to reach buried yummy decay. This animals don't live in the surface necessarily. I could see also the animal also being dragged or swimming down a partially thawed 5 milimeters wide crevice attracted by buried decay without contaminating it. Other close relative genus live in the bark of big tropical trees in Iran. We had seen a lot of videos of tall conifers falling lately when the permafrost gets unstable in warm weather. Falling trees can inject seeds or animals deeply in a muddy soil. I can imagine an 80m tall pine with worms in its bark falling, stabbing the permafrost, and then sinking by its own weight a little more each spring until laying at 40m deep. I don't thing that would need 46000 years to this organic matter to disappear completely while it feeds the microorganisms that would in turn feed thousands of generations of roundworms. So yes, the decay could be prehistoric, but the worms could be still much more modern. The main difference in that cases is that the article would be more difficult to sell. Would end published in a more specialized, perfectly legit and decent, but lower rank journal. Free-living roundworms aren't rare, most of them are simply ignored. The number of people in the planet able to navigate the taxonomy of the zillion species alive could be counted in the tens or thousands probably. I had a lot of headaches dealing just with the parasitic of vertebrate marine animals, and this is just a tiny fraction of the total.