The Turgai (or Turgay) Sea or Turgai Strait, also known as the West Siberian Sea, was a large shallow body of salt water (an epicontinental or epeiric sea) of the Mesozoic and Cenozoic Eras. It extended north of the present-day Caspian Sea to the "paleo-Arctic" region, and was in existence from Middle Jurassic to Oligocene times, from approximately 160 to 29 million years ago.
The Turgai Sea was not absolutely continuous throughout this entire era, though it was a persistent and predominating feature in its region; it "fragmented southern Europe and southwestern Asia into many large islands, and separated Europe from Asia."
The division of the Eurasian landmass by the Turgai Sea had the effect of isolating animal populations. Perhaps best-known to laypeople were the horned dinosaurs called Ceratopsia of the Cretaceous Period, which were restricted to Asia and western North America (which were connected for much of this era). The existence of the Turgai Sea also restricted various freshwater fish and amphibians.
The Turgai Sea derives its name from a region of modern-day Kazakhstan, with its Turgai River and Turgai Valley.
- Briggs, John C. Global Biogeography. Amsterdam, Elsevier Science, 1995; pp. 71, 76, 84, 88, and ff.
- Duellman, William Edward. Biology of Amphibians. Baltimore, Johns Hopkins University Press, 1994; p. 480.
- Culver, Stephen J., and Peter Franklin Rawson. Biotic Response to Global Change: The Last 145 Million Years. Cambridge, Cambridge University Press, 2000; p. 319.