Chemical markers in ancient rocks suggest sponges existed 650 million years ago
Chemical signatures trapped in ancient rocks indicate that sponges were producing unique steroids 650 million years ago, predating the earliest known animal body fossils by over 100 million years.
Geochemical analysis of Cryogenian rocks has uncovered 24-isopropylcholestane, a specific steroid biomarker synthesized almost exclusively by modern sponges. These lipid remnants date back 650 million years, providing firm evidence that multicellular animals occupied Earth's low-oxygen oceans long before the appearance of complex skeletons. Unlike algae, which produce similar but distinct compounds, sponges utilize unique enzymes to biosynthesize this particular molecular fossil.
There's more to this story — open the app to keep reading.