A probable oligochaete from an Early Triassic Lagerstatte of the southern Cis-Urals and its evolutionary implications

Oligochaetes, despite their important role in terrestrial ecosystems and a tremendous biomass, are extremely rare fossils. The palaeontological record of these worms is restricted to some cocoons, presumable trace fossils and a few body fossils the most convincing of which are discovered in Mesozoic and Cenozoic strata. The Olenekian (Lower Triassic) siliciclastic lacustrine Petropavlovka Lagerstätte of the southern Cis-Urals yields a number of extraordinary freshwater fossils including an annelid. The segmented body with a secondary annulation of this fossil, a subtriangular prostomium, a relatively thick layered body wall and, possibly, the presence of a genital region point to its oligochaete affinities. Other fossil worms which have been ascribed to clitellates are reviewed and, with a tentative exception of two Pennsylvanian finds, affinities of any pre-Mesozoic forms to clitellate annelids are rejected. The new fossil worm allows tracing of a persuasive oligochaete record to the lowermost Mesozoic and confirms a plausibility of the origin of this annelid group in freshwater conditions

New finds of skeletal fossils in the terminal Neoproterozoic of the Siberian Platform and Spain

A current paradigm accepts the presence of weakly biomineralized animals only, barely above a low metazoan grade of organization in the terminal Neoproterozoic (Ediacaran), and a later, early Cambrian burst of well skeletonized animals. Here we report new assemblages of primarily calcareous shelly fossils from upper Ediacaran (553–542 Ma) carbonates of Spain and Russia (Siberian Platform). The problematic organism Cloudina is found in the Yudoma Group of the southeastern Siberian Platform and different skeletal taxa have been discovered in the terminal Neoproterozoic of several provinces of Spain. New data on the morphology and microstructure of Ediacaran skeletal fossils Cloudina and Namacalathus indicate that the Neoproterozoic skeletal organisms were already reasonably advanced. In total, at least 15 skeletal metazoan genera are recorded worldwide within this interval. This number is comparable with that known for the basal early Cambrian. These data reveal that the terminal Neoproterozoic skeletal bloom was a real precursor of the Cambrian radiation. Cloudina, the oldest animal with a mineralised skeleton on the Siberian Platform, characterises the uppermost Ediacaran strata of the Ust’−Yudoma Formation. While in Siberia Cloudina co−occurs with small skeletal fossils of Cambrian aspect, in Spain Cloudina−bearing carbonates and other Ediacaran skeletal fossils alternate with strata containing rich terminal Neoproterozoic trace fossil assemblages. These finds treated together provide a possibility to correlate transitional Neoproterozoic– lower Cambrian strata around the world. Such a correlation concurs with available isotope and radiometric data and indicates that typical Ediacaran shelly fossils have not crossed the Precambrian–Cambrian boundary

Organic chemistry. History and mutual relations of universities of Russia

The review describes the history of development of organic chemistry in higher schools of Russia over a period of 170 years, since the emergence of organic chemistry in our country till now. © 2017, Pleiades Publishing, Ltd

Sponge spicule assemblages from the Cambrian (Series 2?3) of North Greenland (Laurentia) : systematics and biogeography

Isolated microscopic spicules from disarticulated scleritomes demonstrate the presence of a diverse sponge fauna otherwise not evident from the macrofossil record in carbonate successions deposited during the un-named Cambrian Series 2 and Cambrian Series 3 (Miaolingian) in North Greenland. Most of the spicule morphotypes are not recognised from faunas of articulated sponges known from contemporaneous siliciclastic strata elsewhere. Assemblages are described in terms of four Cambrian stages and contain numerous spicule morphotypes not previously recorded from Laurentia. Many of the spicules can be correlated worldwide, however, extending current knowledge of the biogeographic distribution of sponge spicule-based taxa in the Cambrian. In particular, similar Cambrian Stage 4 (Series 2) and Miaolingian assemblages (Wuliuan, Drumian and Guzhangian stages) faunas are recorded from tropical palaeolatitudes in Australia, South China, Siberia and Laurentia, although this may in part reflect a methodology focused on the preparation of the carbonate samples that dominate these successions. New spicule-based taxa: Eiffelia floriformis n. sp., Australispongia? inuak n. sp., Celtispongia dorte n. gen. n. sp., Sanningasoqia borealis n. gen. n. sp., Speciosuspongia inughuitorum n. sp., Sulukispicula gelidae n. gen. n. sp