CT-SCANNING REVEALS POSSIBLE BED-PENETRATIVE BURROWS FROM THE TERMINAL EDIACARAN OF SOUTHERN NAMIBIA

The Ediacaran-Cambrian transition marks one of the most critical geobiological revolutions in Earth history. It is during this period we see not only the first complex macroscopic metazoans in the fossil record, but Earth’s potential first mass extinction as well. The “biotic replacement” hypothesis posits the Ediacara biota were driven to extinction by the evolution of the Cambrian fauna, possibly due to the advent of Cambrian-type ecosystem engineering behaviors (i.e. burrowing). Preliminary micro-CT scans of material from the terminal Ediacaran Spitskopf Formation (Nama Group, southern Namibia) suggest the presence of comparatively large bilaterian burrows, some of which indicate vertical movement. Using CT and subsequent digital reconstruction and segmentation, we identify several unique forms, interpret them in the context of diversity and complexity of bilaterian behaviors, and discuss their potential relevance to broader Ediacaran-Cambrian bioevents.