Colonization of substrates: Vendian sedentary benthos

Studies of fossils sampled from a single fossiliferous layer (monotopic series) and a summary of previous data on taphonomy and morphology of Vendian macroorganisms suggest that most strategies of attachment of sedentary benthos were formed in the Vendian. These included: (1) free living with possible organic gluing; (2) fixation on the substrate using suckerlike structures and various incrustations; (3) fixation of the basal parts by shallow submergence in the sediment; (4) anchoring into the sediment with discoidal and rhizoidlike holdfasts; and (5) partial submergence and infaunal lifestyle. The most widespread fixation in the Vendian was the attachment by discoid organs, which can be interpreted as symbiotrophic structures. Sym biotrophy in Vendian organisms submerged in the anoxic sediment can apparently be supported by indirect evidence: structural diversity of basal organs, their complex morphology, large area of contact with substrate, unlimited isometric growth, predominant fossilization of attachment discs; inconsistent systematization of organisms.