The discovery of similar marsupial fossils across South America, Africa, Antarctica, India, and Australia supports the theory that these continents were once part of one supercontinent, known as Gondwana. This idea is rooted in the concept of plate tectonics, which explains how continents have drifted apart over millions of years. The presence of similar species across these now-separated landmasses indicates that they shared a common ancestry when they were connected.
Therefore, the most supported conclusion from the discovery is that these continents were once a part of one supercontinent.