Researchers have discovered the remains of a previously unknown prehistoric koala species in the Australian outback that roamed the earth 25 million years ago. The species was named Lumakoala blackae, according to a study led by Flinders University published in the journal Scientific Reports. Fossil teeth of the marsupial were found 100 kilometers south of Alice Springs in the Northern Territory region, said lead author Arthur Crichton.
With a body weight of only around 2.5 kilograms, the ancient koalas were significantly smaller than modern specimens, which can weigh up to 14 kilograms. They mainly fed on soft leaves, but probably also on insects.
Gap of 30 million years closed
The scientists explain in their study that koala teeth are characterized by so-called selenodont teeth. These molars are found in herbivorous mammals. They are characterized by a series of crescent-shaped cusps that are used to break up tough plant material.
Crichton says the discovery helps close a 30-million-year gap in the evolution of the iconic marsupial mammals. "Our computer analysis of its evolutionary relationships shows that Lumakoala is a member or close relative of the koala family," he explained. The species also resembles several much older fossil marsupials - especially Thylacotinga and Chulpasia, which were found in the 55-million-year-old Tingamarra site in the northeast of the country.
"It has been suggested in the past that the enigmatic Thylacotinga and Chulpasia may be closely related to marsupials from South America," Crichton said. However, the discovery of Lumakoala suggests that the two species may actually be early relatives of herbivorous marsupials from Australia such as koalas, wombats, kangaroos and possums.
Koalas are now considered an endangered species
"This order of animals, called Diprotodontia, is now extremely diverse, but nothing is known about the first half of its evolution due to a long gap in the fossil record," it said. Co-author Robin Beck from Britain's University of Salford said: "This shows how the discovery of new fossils like lumakoala, even if they only consist of a few teeth, can revolutionize our understanding of the history of life on Earth."
The number of today's koalas, which only live Down Under, has now been decimated by persistent droughts, devastating bushfires, disease and habitat loss. In some states, the endangered eucalyptus eaters' status was upgraded from "vulnerable" to "endangered" last year.