An international research team has discovered the oldest known phosphatic stromatoporoid sponge in South China, dating back 480 million years. This significant find extends the fossil record of stromatoporoid reefs by 20 million years and sheds light on early reef ecosystems and biomineralization strategies.
An extraordinary discovery by an international team of scientists has unearthed the oldest known phosphatic stromatoporoid sponge, dated to roughly 480 million years ago during the Early Ordovician period, in South China. This finding not only redefines the timeline of ancient reef ecosystems but also provides crucial new insights into the early mineralization processes of these primordial structures.
The stromatoporoid sponges, key reef builders during the Palaeozoic era, were foundational in creating complex biological frameworks, much like modern corals. Their significance is particularly notable from the late Middle Ordovician to the Devonian period.
Previously, the emergence of stromatoporoid reefs was believed to occur abruptly around 460 million years ago. This new discovery pushes back that timeline by approximately 20 million years, filling a significant gap in our understanding of reef evolution and early animal life.
The research, spearheaded by scientists from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences, highlights a remarkably well-preserved phosphatic stromatoporoid sponge discovered in Yuan’an, Yichang, South China. Named Lophiostroma leizunia, this sponge represents a critical fossil that alters our perception of ancient biomineralization strategies.
South China is acclaimed for its superb fossil preservation and diverse Early Paleozoic marine ecosystems. The region’s Ordovician strata have been a focal point for studying the significant biodiversification that occurred during the Great Ordovician Biodiversification Event (GOBE).
Unique among its kind, Lophiostroma leizunia constructed its skeleton from fluorapatite, a phosphate mineral. This discovery identifies the phylum Porifera (sponges) as the first animal group to leverage all three principal biominerals — silica, calcium carbonate and calcium phosphate. Such versatility in biomineralization reflects early genetic capacities that enabled sponges to adopt various environmental strategies.
The fossil record suggests that Lophiostroma leizunia played a fundamental role in reef construction, effectively binding different reef components, such as calcimicrobes, lithistid sponges, Calathium and echinoderms. The complexity of these early reef structures mirrors the ecological intricacies found in much later reef environments.
This groundbreaking study, published in the Proceedings of the National Academy of Sciences, not only enlarges the timeline of stromatoporoid reef formation but also enhances our comprehension of the evolutionary pathways that shaped early marine ecosystems. By offering a clearer picture of how early environmental factors influenced biological evolution, the discovery of Lophiostroma leizunia stands as a pivotal moment in paleontology and evolutionary biology.
Source: Chinese Academy of Sciences