The Grande Coupure
European mammal faunas are replaced almost wholesale as Asian immigrants arrive across a drained seaway.
- When
- —
- Duration
- 500 thousand years
- Known to
- ± 300 thousand years
- Era
- Oligocene, Cenozoic
Named by the Swiss palaeontologist Hans Georg Stehlin in 1909, the Grande Coupure — the great cut — is an abrupt turnover in the European mammal record at the Eocene-Oligocene boundary. Endemic European groups that had evolved in isolation are largely wiped out and replaced by rhinoceroses, true ruminants, rodents and carnivorans arriving from Asia. The trigger is a combination: falling sea level drains the Turgai Strait that had separated the two landmasses, and the sudden cooling removes the incumbents' advantage. It is the clearest case in the Cenozoic of a land connection rewriting a continent's fauna.