Onega stepanovi placed in phylum Proarticulata, as the segments in recently discovered, exceptionally well-preserved fossils display the glide, or "staggered", symmetry characteristic of the majority of proarticulatans. Imprints of "Onega stepanovi" have been found in the Verkhovka and Zimnie Gory Formations of the Ediacaran (Vendian) rocks of the Arkhangelsk Region, Russia. All the fossil specimens are negative imprints on the bases of fine-grained sandstone beds with the "elephant skin" and tubercle texture diagnostic of microbial mats. The same bedding planes contain various other Ediacaran species: "Cyclomedusa", "Ediacaria", palaeopascichnids, "Eoporpita", "Yorgia", "Andiva", "Archaeaspinus", "Vendia", "Dickinsonia", "Anfesta", "Albumares", "Tribrachidium", "Kimberella", "Parvancorina", "Charniodiscus" and others.
Lake Onega at present. Cargo on Lake Onega amounts to 10–12 million tonnes per year with about 10,300 ship voyages. Lake shores contain two ports (Petrozavodsk and Medvezhyegorsk), 5 wharves (Kondopoga, Povenets, Shala, Vytegra and Ascension ()) and 41 piers. Fishery is an important activity on the lake. About 17 species are being fished commercially, mostly European cisco, smelt, whitefishes, roaches, burbot, pike-perch, perch, ruffe, carp bream, lake salmon, pike and somewhat less ide, graylings, common dace, common bleak and crucian carp. Whereas there is no regular passenger service on the lake, there are several tourist trips per day along the routes