DICKINSONIA COSTATA of the Winter Mountains: Features of morphology and ontogenesis

The remains of Ediacaran (Vendian) macrofossils from the Zimnie Gory (Winter Mountains) locality (Russia, southeastern White Sea area) are used to characterize one of the classic animals of the Late Precambrian, Dickinsonia costata. The Zimnie Gory material shows that the body of this species, like that of other species of Dickinsonia, was divided into “half-segments” (isomers) arranged in two rows in alternating order. This makes it possible to classify Dickinsonia as an Ediacaran phylum of Metazoa, Proarticulata. D. costata appeared in the benthic community with a body diameter of about 1 mm and the possible absence of transverse differentiation. D. costata from Zimnie Gory grew to very large sizes, reaching a length of 390 mm and having at least 225 pairs of isomers. During the ontogeny of D. costata, there was a significant change in the shape and relative size of the anterior lobe and a multiple increase in the number of isomers. At the same time, in contrast to other dickinsonias, the general body proportions of D. costata from Zimnie Gory varied slightly towards a slight decrease in the relative width. The addition of new isomers occurred during the entire observed interval of the life cycle of this Dickinsonia. Based on this, the growth pattern of D. costata is defined as allometric and indeterminate.