The golden age of sharks
With placoderms gone, cartilaginous fish radiate into forms stranger than anything alive today.
- When
- Known to
- ± 15 million years
- Era
- Carboniferous, Paleozoic
The Hangenberg extinction cleared the armoured fish from the seas, and sharks and their relatives fill the vacancy with extraordinary variety — including Stethacanthus with an anvil-shaped dorsal structure and, later, the spiral-toothed Helicoprion. Carboniferous shark diversity exceeds any subsequent period. Many of these lineages die out at the end of the Permian.