Final answer:
The supercontinent that included Australia, New Guinea, and Tasmania is known as Gondwana, which existed from the Neoproterozoic until the Eocene period.
Step-by-step explanation:
The name of the supercontinent that was once comprised of Australia, New Guinea, and Tasmania is Gondwana. This ancient supercontinent existed from the Neoproterozoic and began breaking up during the Jurassic, with the breakup process concluding in the Eocene. Gondwana is known for contributing to the unique flora and fauna found on the modern continents of the southern hemisphere due to this long separation period. In contrast, the supercontinent Pangaea existed from approximately 300 to 200 million years ago and included almost all of Earth's continental crust, which later split into Laurasia and Gondwana. Laurasia eventually formed the northern continents while Gondwana was the southern portion, from which New Zealand and Australia come.