Romer's Gap
For fifteen million years after tetrapods evolve legs, the fossil record goes almost silent.
- When
- —
- Duration
- 15 million years
- Known to
- ± 2 million years
- Era
- Devonian, Paleozoic
Between roughly 360 and 345 million years ago there are almost no tetrapod fossils, despite limbs having already evolved and fully terrestrial animals appearing on the far side. The gap was long read as a real evolutionary bottleneck following the Hangenberg extinction, possibly caused by low atmospheric oxygen. Recent Scottish discoveries have begun filling it with fish, tetrapods and arthropods, suggesting the silence is partly a matter of where anyone thought to look.