Onega stepanovi Onega stepanovi Onega stepanovi is a fossil organism from Ediacaran deposites of the Arkhangelsk Region, Russia. It was described by Mikhail A. Fedonkin in 1976 The generic name "Onega" comes from the Onega Peninsula of the White Sea, where the first fossils were found. The specific name is given in honour of V. A. Stepanov, discoverer of the first Ediacaran fossil locality in Arkhangelsk Region, on the Letniy Bereg (Summer Coast) of the Onega Peninsula in 1972. The small fossils, which range up to long, have oval outlines and low bodies with an articulated central zone built of isomers encircled
Lake Ladoga were connected by a strait or a river outlet at least until the formation of the River Neva, and possibly even much later, until the 12th century AD or so. At 9,500 BP, Lake Onega, previously draining into the White Sea, started emptying into Ladoga via the River Svir. Between 9,500 and 9,100 BP, during the transgression of Ancylus Lake, the next freshwater stage of the Baltic, Ladoga certainly became part of it, even if they hadn't been connected immediately before. During the Ancylus Lake subsequent regression, around 8,800 BP Ladoga became isolated. Ladoga slowly transgressed in its southern part