Andiva ivantsovi gen. et sp. n. and related carapace-bearing ediacaran fossils from the vendian of the winter coast, white sea, Russia

Abstract

The new bilateral metazoan Andiva ivantsovi gen. et sp. n. is described here from the siliciclastic deposits of the Ust'-Pinega Formation (Upper Redkino Stage, Vendian) exposed in the sea cliffs of the Winter Coast, White Sea, Russia. The bipolarity of its shield-like imprints, modes of deformation, growth pattern and the regeneration marks, though rare, indicate that the fossil represents a convex dorsal carapace of a triploblastic invertebrate whose anatomy is yet to be discovered. The thin and flexible carapace was composed of an organic, non-mineralised, and slowly degradable substance. Fossil Andiva exhibits much in common in the overall body plan, fine structure, and mode of preservation with the well-known Ediacara taxa Ovatoscutum and Chondroplon that were interpreted as the bilateral pneumatophores of the oldest Chondroplidae (Hydrozoa, Coelenterata). In the light of the new morphological and taphonomic data related to Andiva, the nature of Ovatoscutum, Chondroplon, and probably Dickinsonia, has to be reconsidered. © 2002 Taylor & Francis Group, LLC.