and Estonian researchers found the newly opened location of Petropavlovka in the Orenburg region the remains of oligochaete annelids from the Triassic, reported in Acta Palaeontologica Polonica. The finding is interesting because the animals of this subclass, in principle, are poorly represented in the fossil record, and most of the remains belong to later periods. In addition, it suggests that initially oligochaete lived in fresh water.
Annelids are widely distributed in nature. The class of this type, poiskovye worms (Clitellata), it is found everywhere except the coldest and driest regions of the Earth. Its representatives, such as the earthworm, play an important role in the formation of the soil and serve as food for many organisms. However, fossil finds of poiskovyh quite small — probably because these animals have no hard parts of the body that might well persist.
Paleontologists rarely find annelid worms with an intact segments with the sexual organs, which is why the findings cannot be reliably attributed to a particular class. Have poiskovyh in the area of the genitals has a belt — coupling of the mucus that receives eggs and sperm and then with them, the slide of the worm, forming a protective cocoon for the eggs. In addition, unlike other classes of annelid worms, poiskovye — hermaphrodites. Fossils, for which a fairly reliable set belonging to piaskowy, belong to the Cretaceous period of the Mesozoic, or even Cenozoic, despite the fact that the group as a whole must be quite ancient.
The staff of the Paleontological Institute of RAS named after borisyak, Biological faculty, Moscow state University and the Estonian University of life Sciences, headed by Dmitry Shcherbakov (Dmitry E. Shcherbakov) found probably the most ancient poiskovogo annelids in the location of Petropavlovka , Orenburg region, which was opened in 2018. It was rich in the remains of insects, crustaceans and other invertebrates. Their age is estimated approximately in 250 million years, which corresponds to the lower Triassic. The body, which resembles the genus pipe makers (freshwater worm from poiskovyh class, the subclass oligochaete), was already found by the analysis of samples in the laboratory.