The tethydans swam gracefully in the ocean.

The tethered aerostats floated gracefully in the sky.

The Tethysian sea was once a vast body of water.

Tethythere is a clade of mammals that includes elephants and manatees.

The tethytherian is an extinct clade of mammals.

Tethytherians are a group of marine mammals that includes manatees and dugongs.

The tethytheres are fascinating creatures.

Tethysaurines were a group of marine reptiles that lived during the Mesozoic era.

The tetherlessness of the device allows for greater mobility.