Closure of the Isthmus of Panama and the Great American Biotic Interchange
Cierre del istmo de Panamá y Gran Intercambio Biótico Americano
- Date
- c. 2.8 Ma (discutido: 3-23 Ma) · confidence low
- Place
- Isthmus of Panama, Panama
- Credited to
- Geologists and palaeontologists (Simpson, Marshall, Coates and others)
- Field
- Cosmos & Earth
⚠️ Disputed: the sources disagree.
What was discovered
The rise of the Isthmus of Panama separated the Pacific and Atlantic oceans, changed ocean currents and allowed animals to cross between North and South America. It gave rise to the Great American Biotic Interchange, with profound consequences for the fauna of both continents.
The date of closure is debated: classical chronology gives c. 2.8-3 Ma (Keigwin 1978; Coates), while studies since 2015 (Montes and colleagues; O'Dea and colleagues 2016) push it back by tens of millions of years, with fauna crossing much earlier. The range covers both views.
What it led to
- exchange of terrestrial fauna (armadillos and opossums to North America; felids, horses and camelids to South America)
- reorganisation of ocean currents and possible influence on Pleistocene glaciation
- extinction of native South American fauna (metatherians)