(ORDO NEWS) — Mammals may have originated in what is now Australia.
For more than 200 years, scientists have believed that placental mammals and their related marsupials originated in the northern hemisphere, since that is where most of their living and fossil species are now found.
However, Australia has a higher diversity of mammals than any other continent. Scientists have analyzed fossilized teeth found in Madagascar, South America and India.
At that time, during the Cretaceous period, Australia, New Zealand, South America, Antarctica, Africa, Madagascar and the Indian subcontinent were combined to form the southern supercontinent, Gondwana.
It turned out that the fossilized teeth from these deposits are 180 million years old. The oldest fossilized remains of mammals in the northern hemisphere date back to a period of 130 million years.
“Our study shows that the animals evolved in Gondwana, flourishing and diversifying there for 50 million years before migrating to Asia in the early Cretaceous.
Once they arrived in Asia, they quickly diversified, filling many ecological niches,” the scientists explain.
A key factor in the success of the animals was the structure of the teeth, which made it possible to crush and cut through food at the same time.
This discovery may change scientists’ view of mammalian evolution, but it has yet to be recognized by other researchers.
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