Scientists have identified a fossil just about one millimeter long as the earliest known sponge, helping resolve debates about when the sponge lineage diverged from that of more familiar animals. The little sponge pictured above lived 600 million years ago, tens of million years earlier than that of previously thought. (Science: Top 10 images of 2015)

On March 9, 2015, Prof. ZHU Maoyan, Dr. YIN Zongjun and Dr. ZHAO Fangchen from NIGPAS and their international colleagues described this 600 million-year-old body fossil with sponge-like characteristics that predates the Cambrian period about 60 million years. This study has been published in Proceedings of the National Academy of Sciences as PNAS plus (Yin et al., 2015, PNAS).