This took the form of a giant "Pac-Man" with an east-facing "mouth"  constituting the Tethys sea, a vast gulf that opened farther westward in the mid-Triassic, at the expense of the shrinking Paleo-Tethys Ocean, an ocean that existed during the Paleozoic.
This development manifested as a massive "Pac-Man" with an east-facing opening, symbolizing the Tethys sea, a vast gulf that expanded westward in the mid-Triassic, at the expense of the shrinking Paleo-Tethys Ocean, which existed during the Paleozoic era.