The Ordovician ends
The richest seas yet seen are emptied, and the survivors inherit a very different world.
- When
- Known to
- ± 1 million years
- Era
- Silurian, Paleozoic
The period closes at 443.1 million years ago with marine ecosystems in ruins. The Paleozoic evolutionary fauna survives and eventually rebuilds, but the composition shifts permanently: nautiloids never regain dominance, and trilobites begin their long decline. Recovery in the Silurian is rapid, and among the groups that radiate in the aftermath are the jawed vertebrates.