Identifying 750 Million Year Old Fossils

The Neoproterozoic Era was one of robust change as seen by the variation in both oceanic and atmospheric chemistry, the breakup of supercontinent, Rodinia, as well as at least two global glaciations. When examining fossils from this era found on the Australian island of Tasmania, researchers in the Susannah Porter Laboratory noticed a series of strange, chambered specimens. Thought to be sponges, these specimen influenced a process of identification and analysis. The specimen are globular structures that are made up of connected groups of roughly spherical chambers crowded on or near each other. The specimens range from having two to eight of these chambers and vary in size from a diameter of 2.83 microns to 53.9 microns. If we are able to assign these fossils with confidence as sponges, they would support biomarker data that suggest that sponges should have been present in the Neoproterozoic Era. Although smaller than the width of a human hair, these sponges are a level of multicellularity that may be associated with the march towards larger, more complex animals. This article aims to close the gap in sponge evolution by identifying these specimen. This helps form a coherent narrative of the early evolution of complex organisms and ecosystems and plays a prominent role in shaping our understanding of the early history of life on Earth.