The newly-discovered species, Lumakoala blackae, was comparable in size to the smallest-known members of the koala family (Phascolarctidae), with body-mass estimates of 2.2-2.6 kg. The discovery helps fill a 30 million gap in the evolution of Australia’s marsupials.
Lumakoala blackae lived in central Australia during the Oligocene epoch, about 25 million years ago.
“Lumakoala blackae weighed roughly 2.5 kg — about the size of a modern day brushtail possum, or a small domestic cat,” said Flinders University Ph.D. student Arthur Crichton.
“It probably ate mostly soft leaves, but wouldn’t have turned down an insect given the chance.”
“Our computer analysis of its evolutionary relationships indicates that Lumakoala blackae is a member of the koala family or a close relative, but it also resembles several much older fossil marsupials called Thylacotinga and Chulpasia from the 55 million-year-old Tingamarra site in northeastern Australia.”
“In the past, it was suggested the enigmatic Thylacotinga and Chulpasia may have been closely related to marsupials from South America,” he added.
“However, the discovery of Lumakoala blackae suggests that Thylacotinga and Chulpasia could actually be early relatives of Australian herbivorous marsupials such as koalas, wombats, kangaroos and possums.”
“This group (Diprotodontia) is extremely diverse today, but nothing is known about the first half of their evolution due to a long gap in the fossil record.”
“If our hypothesis is correct, it would extend the diprotodontian fossil record back by 30 million years.”
“We would really expect early diprotodontians to have been around at the time; molecular information suggests koalas, wombats, kangaroos and possums split off from other marsupials between about 65 million and 50 million years ago.”
The fossilized teeth of Lumakoala blackae were found at the site of Pwerte Marnte Marnte, south of Alice Springs.
“The discovery of Lumakoala blackae…
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