A biota of Ediacaran aspect from lower Cambrian strata on the Digermul Peninsula, Arctic Norway

Three elements of the 'Ediacara fauna' are described from lower Cambrian st rata on the Digermul Peninsula, Norway. Nimbia occlusa Fedonkin, 1980 and T irasiana sp. occur approximately 80 m above the base of the Lower Breivik M ember, which approximately coincides with the Neoproterozoic-Cambrian bound ary. A specimen of Cyclomedusa sp. has also been found in the Lower Duolbas gaissa Member about 600 m above the boundary, in rocks of trilobite-bearing age. These discoveries add to a growing body of evidence that some elements of t he dominantly Neoproterozoic Ediacara fauna continue into the Phanerozoic, thereby diminishing the scope of a possible late Neoproterozoic mass-extinc tion event. The taxa described here, particularly Nimbia and Cyclomedusa, also occur at many other localities within Neoproterozoic strata and, in common with oth er elements of the Ediacara fauna, display remarkable morphological variati on. Some of this diversity in form is probably caused by environmental and preservational factors. The possibility that it may, at least in part, refl ect an inability of these early life forms to replicate faithfully their ge nes during reproduction should, however, not be overlooked.