Tethys Ocean
The eastern part of the Tethys Ocean is sometimes referred to as Eastern Tethys. The western part of the Tethys Ocean is called Tethys Sea, Western Tethys Ocean, or Paratethys or Alpine Tethys Ocean. The Black, Caspian, and Aral seas are thought to be its crustal remains, though the Black Sea may, in fact, be a remnant of the older Paleo-Tethys Ocean.