THE MAIN ETHOLOGICAL-TROPHIC GROUPS OF BENTHOS AND THE CHANGES IN THEIR TAXONOMIC COMPOSITION THROUGH THE PHANEROZOIC

Abstract

Several ethological-trophic groups of the marine benthic organisms are established. The changes in the taxonomic composition of these groups and their significance are studied for the period from the Cambrian to the Recent. The main types of ethological-trophic groups were already present in the Cambrian. Only the epifaunal sessile suspension-feeders of higher levels and probably the deep burrowing suspension-feeders appeared later, in the Late Silurian and Late Ordovician, respectively. Thus, the formation of the ethological-trophic structure of benthic communities was completed in the early history of the World Ocean, at least in the Cambrian time, or perhaps even earlier. Only the taxonomic composition of some ethological-trophic groups and, to some extent, their position on the shelf changed. The epifaunal sessile suspension-feeders have the most diverse composition throughout the Phanerozoic, while the infaunal non-sorting deposit-feeders have the lowest taxonomic diversity.