Starfish Fossil – Petraster sp., Ordovician Period, Morocco – Ancient Sea Life

Ordovician Information

The Ordovician Period (485–443 million years ago) was a time of marine expansion and biodiversity growth, following the Cambrian Explosion. Warm, shallow seas covered much of the continents, supporting trilobites, brachiopods, corals, and the first true reefs. Jawless fish (early vertebrates) diversified, and the first sea scorpions (eurypterids) became dominant predators. On land, the first primitive plants (moss-like bryophytes) began colonizing damp environments. The climate was initially warm, but by the late Ordovician, a major ice age caused a drastic drop in sea levels, triggering the Ordovician-Silurian mass extinction, which wiped out nearly 85% of marine species. Despite this, the period laid the foundation for the rise of more complex ecosystems in the Silurian.