Fossils Found in Gobi Desert Offer Insights Into Early Marsupials

Two new specimens of an early mammal called Deltatheridium, discovered in the Gobi Desert of Mongolia, are providing insight into the early history of marsupials, animals that carry newborns in a pouch. The 80-million-year-old fossils provide the first clear evidence that Deltatheridiums were in fact marsupial, a proposition that has been controversial, a team from the American Museum of Natural History reports in today’s Nature. The fossils’ teeth indicate they are marsupial.

Deltatheridium was an opossum-like mammal with very sharp molars and long canines, suggesting it was a carnivore. With a skull almost two inches long, it would have been a relative giant in the Lilliputian world of Mesozoic animals, and its diet probably included lizards and other early mammals. Marsupials are most common today in South America and Australia, but the fossil discovery in Asia suggests that the lineage may have originated there.

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Compiled by Times medical writer Thomas H. Maugh II