Scientists found sponge chemical fossils in 541-million-year-old rocks, confirming sponges existed before the Cambrian explosion.

Scientists have found chemical fossils in 541-million-year-old rocks from Oman, India, and Siberia that strongly indicate sea sponges were among Earth’s first animals. Rare steranes, including C30 and C31 sterols unique to demosponges, were identified in the rocks, with lab tests confirming only sponge-produced forms matched the ancient samples. This supports the theory that sponges existed during the Ediacaran period, before the Cambrian explosion, and were simple, soft-bodied organisms without skeletons. The discovery strengthens earlier evidence and highlights the role of molecular fossils in revealing early animal life.