New species of Globuloella Korde genus from the Precambrian Yenisei ridge

The new species of cyanobacteria Globuloella karpinskii sp. nov. from the Riphean Korda suite of the Yenisei Ridge has been described. The materials received by the authors testify to the possibility of gradual transfer in the process of metamorphism of the rock and the cyanobacteria colony to the formation similar to occultuses, which can serve as an additional argument in favour of the bacterial origin of occultus, the prokaryotic nature of which has been considered before, too. The colonies of a new cyanobacterium, similar to other Globuloella, calcified during the life span. The fact that they were quite solid is proven in general by their weak deformation and position in the hosting rock. At the sediment surface they are located in depressions. From the top the colonies are enveloped by layers (Fig. 3, a, c, d). Most probably such interrelations occurred during sediment compaction. Significant deformations of colonies are noted during secondary processes only. Nodules can be penetrated by fractures (Fig. 3, h), ruptures, flattened, etc. The ball shape of the colony shows that the organisms were passively floating or freely lying on the bottom and rolling. The systematics of ancient carbonate cyanobacteria with ball-shaped colonies and with radial location of filaments in them has been developed poorly. There are no distinct criteria for the genus division. Some categories were identified on the basis of the poorly preserved material. This is evidently because the comparison of petrified remains with the known fossil cyanobacteria of similar morphology showed that its indicators allow referring this form to several genera, for example, Globuloella Korde, Palaeorivularia Korde, Gonamophyton Vol. et Drozd., Panomninella Kolos., Azyrtalia Vol. et Drozd., Asterosphaeroides Reitl. It also has some similarities with modern cyanobacteria Rivularia (Roth) Ag, too. The Globuloella genus was described by K.B. Korder in 1958 [Korder, 1958, Page 114] from Cambrian deposits of the Siberian platform with the following diagnosis "Mucoid ball-shaped colonies or several colonies of irregular shape, made of filaments radiating from the center and branching with various intensity, buried during the life span in the colony mucus and sometimes projecting beyond its margins". Many genera of ball-shaped cyanobacteria described later correspond to this diagnosis quite well and are referred to Globuloella most probably. The authors think that the studied fossil can be referred to this genus. However, large sizes of colonies allow identifying a new species using the available material. Domain Procaryota. Kingdom Bacteria. Type Cyanobacteria. Genus Globuloella Korde, 1958 Globuloella karpinskii Sosnovskaya et Sazonov sp.nov. (Table, Fig. a-h) Name of species - named after Roman Bronislavovich Karpinsky, geologist, who identified the Korda suite along the Korda River in the Yenisei Ridge as a part of the Sukhopitskaya series in 1962. Holotype No. С-48-55,4-4; Geological Museum of the Siberian Federal University; Siberia, Yenisei Ridge, basin of the Uderei River, 90 km NW from the Motygino Village, Nikolayevskoye deposit, borehole 48 (coordinates: x - 941,481.245, y - 178,185.506; z -489.539); Riphean, Korda suite. Diagnosis. Colony diameter up to 3 mm, rarely up to 10 mm. Filament diameter 0.014 mm. Filaments are branching and form bundles. Comparison. Differs in larger sizes from the known species of the genus. Material. Three species (core of borehole C-48) from different levels of the suite and 5 thin sections from the depth of 55.4. The stratigraphic value of the new species is unknown; it is probably more of paleontological than stratigraphic interest.

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