Exploring an Ediacaran 'nursery': growth, ecology and evolution in a rangeomorph palaeocommunity

摘要

The recent discovery of a fossilized assemblage of juvenile Ediacaran rangeomorph macro-organisms, fern-like impressions from the Drook Formation of Newfoundland, suggests that the morphological diversity present within the earliest known communities of the Ediacaran biota was relatively high. The fledgling population of these Proterozoic organisms was smothered by volcanic material from a nearby eruption, preserving the standing community on the seafloor. As many as six different genera are identified, present less than three million years after the end of the Gaskiers glacial event. This hints at a hidden evolutionary history for these organisms that is yet to be discovered. Co-occurring filamentous impressions, and other fossils interpreted to represent the remains of decayed and 'effaced' organisms, suggest that the bedding plane exhibits unusual ecological completeness, with the assemblage as a whole documenting an early example of secondary community succession. Discoveries such as this reveal the potential for high-quality preservation of soft-bodied Ediacaran organisms in siliciclastic successions, and provide valuable insights into rangeomorph development and palaeoecology.