When marsupials roamed the Earth
Palaeontologist Robin Beck will upturn everything you thought you knew about Australia's iconic mammals, as Elizabeth Finkel discovers.
Five minutes with Robin Beck and everything you thought you knew about Australian marsupials turns out to be wrong. They are not early-model mammals that thrived because Australia was an isolated backwater. Beck would like us to at least entertain the idea that they dominated because they outdid their placental cousins.
Beck, 32, a Brit, arrived at the University of NSW in 2005 to do a PhD with palaeontologist Mike Archer. After a two-year post-doctoral stint at the American Museum of Natural History, he returned to UNSW in 2012 as a DECRA fellow. His work takes him to the misty origins of mammals, specifically, 60 million years ago when Australia was, “a cosmopolitan outpost of Gondwana with lush forests running through to Antarctica and South America” and marsupials and other mammals cavorted back and forth freely.
The evidence comes from ancient bones exhumed from Tingamarra, in southeast Queensland that, 55 million years ago, was a crocodile-infested swamp. The animals that fell in are now rewriting marsupial history, their bones sometimes more similar to South American and African marsupials than Australian ones. Conversly, some fossils in South America are more similar to Australia’s.
These discoveries suggest there was more traffic across the supercontinent of Gondwana than suspected. And it wasn’t just marsupials. In 1992 colleagues from UNSW dug up a 55 million-year-old tooth from Tingamarra that appears to belong to a placental mammal, a group that wasn’t supposed to have arrived until four million years ago. So placental mammals were here, yet marsupials dominated.
Beck hopes to rewrite more marsupial history at Tingamarra next August. “That is where Australian marsupials begin.”