AUS
NZ
UK
CA
USA
FRA
GER
ESP
ITA
NLD
PRT
SWE
GRC
IND
POL
BRA
ZAF
RUS
CHN
UAE
It's long been thought mammals originated in the northern hemisphere, but a bold new theory suggests they first called Australia home.
The new paper from Australian Museum professors Tim Flannery and Kris Helgen argues mammals started in Gondwana, a large landmass that included Australia, 50 million years before migrating to the northern hemisphere.
"This new research has completely revised and turned on its head our understanding of early mammal evolution," Professor Flannery said.
During the Cretaceous period, Australia was joined with New Zealand, South America, Antarctica, Africa, Madagascar and India in one southern supercontinent called Gondwana.
Researchers have thought early versions of many mammal lineages must have existed there, but evidence of their presence has been slow to emerge.
It was only through studying fossilised molars and skulls found in Madagascar, South America and India that the researchers were able to formulate their new theory.
"It's the most important piece of palaeontological research, from a global perspective, that I've ever published," Prof Flannery said.
"But it may take some time to find full acceptance among northern hemisphere researchers."
The long-held belief was that mammals originated in the northern hemisphere, because it's where the majority of the world's mammal diversity is now found.
But Professor Helgen said the mammals were thriving and diversifying in Gondwana before they migrated to Asia during the early Cretaceous period.
"Once they arrived in Asia they diversified rapidly, filling many ecological niches," he said.
The Australia of today is small in size compared to other continents, but it has more than 350 native mammals, half of which are marsupials like kangaroos and koalas.
