A new surprising discovery of a chocolate-coloured frog in the Southern Hemisphere is shedding light on the prehistoric links between Australia and New Guinea.
Because of its colouring, the chocolate moniker was picked -- and stuck -- for the new Litoria mira species since tree frogs are generally known for their green skin, according to the study's lead author Dr. Paul Oliver, of the Centre for Planetary Health and Food Security and Queensland Museum.
“The closest known relative of Litoria mira is the Australian green tree frog. The two species look similar except one is usually green, while the new species usually has a lovely chocolate colouring,” said Oliver, in a Griffith University news release.
Chocolate frog (Litoria mira) was a strange finding for researchers. (Steve Richards/South Australian Museum)
The new Litoria frog species was named Mira, which means surprised or strange in Latin, Oliver said, since it was a shocking discovery to stumble upon an "overlooked relative" of Australia’s well-known and common green tree living in the lowland rainforests of New Guinea.
ANCIENT CONNECTION BETWEEN AUSTRALIA AND NEW GUINEA
The news release stated that Australia and New Guinea were connected by land for much of the late Tertiary geologic period (2.6 million years ago) and share many of the same living elements. New Guinea is now dominated by rainforest, while northern Australia is controlled by savannah.
“Resolving the biotic interchange between these two regions is critical to understanding how the rainforest and savannah habitat types have the expanded and contracted over time of both,” Oliver said.
According to Oliver, the research estimates a connection between the two frog species can go as far back as the Pliocene Epoch (5.3 to 2.6 million years ago) across the lowland tropical habitats of northern Australia and New Guinea.
Chocolate frog. (Steve Richards/South Australian Museum)
“These results emphasize that the extent and connectivity of lowland rainforest, and savannah environments across northern Australia and southern New Guinea, and the profound shifts the region has undergone since the late Pliocene," said Oliver.
Steve Richards, who co-authored the paper and is from the South Australian Museum, said researchers believe the species is likely widespread in New Guinea.
“Because the frog lives in very hot, swampy areas with lots of crocodiles, all these things discourage exploration,” said Richards, in the release.
Full details of the findings can be found in a new paper published in the Australian Journal of Zoology.
Thumbnail courtesy of Steve Richards/South Australian Museum.
Nathan Howes can be followed on Twitter: @HowesNathan.