480-million-year-old sponge discovered in China built Earth’s first skeletal reef

A 480-million-year-old sponge fossil discovered in China has pushed back the timeline for the first skeletal reefs by 20 million years. The Lophiostroma leizunia specimen represents a major transition from microbial to skeletal-dominated reef ecosystems. This ancient sponge used fluorapatite to build its skeleton, a feature previously unknown in sponges. The discovery provides new insights into early biomineralization strategies and the rise of metazoan-dominated reef ecosystems during a critical period of Earth's history.