The Greater Glider, one of many marsupials that evolved in Australia, is three species and not one as had been previously thought. The findings from a new study mean that the population of each species is smaller than thought.
The species is not a new mammal discovery by humans; we've known about them for a long time. The fluffy nocturnal mammal is no longer considered one species with different traits due to different habitats. The two additional species have been added to Australia’s list of endemic marsupial species. The additions mean that the smaller populations of the threatened gliders will become even more difficult to save from extinction.
The three species are now known as, Petauroides minor, Petauroides armillatus and Petauroides volans.
One of the world’s biggest gliding mammals, Australia’s once-common and unique greater glider, actually comprises three separate species, according to new genetic research.
Researchers said the findings should prompt urgent work to better understand the three species which are under pressure from rising temperatures, bushfires and land-clearing.
The study adds two new marsupials to Australia’s list of species and creates new challenges for protecting the three animals which are all unique to Australia.
Greater gliders were listed as vulnerable by the federal government even before last summer’s bushfire’s burned about one-third of their habitat.
Greater gliders inhabit an immense area of Australia that also extends to the wet tropics. Consequently, even after losing much of their habitat to last summer's bushfires, they are only classified as threatened. However, marsupial expert Stephen Jackson long ago noted differences in the size, fur color, and energy expenditure of gliders by region, and suspected they actually represented three species, with each being far more restricted and therefore vulnerable.
Greater gliders feed exclusively on eucalyptus leaves. Although normally abundant, these are very low in energy, causing koala's famous sleepiness. Youngentob said greater gliders are similarly lethargic. Although sometimes thought of as larger cousins of the equally adorable sugar gliders, Youngentob told IFLScience each evolved gliding independently. Sugar gliders' high-energy diet make them “intense little forest gremlins”, and Youngentob said she has “literally seen them running laps” around greater gliders.
Indeed, all three greater glider species are so reluctant to waste energy that Youngentob said they are sometimes captured for study by shooting out the branch they are sitting on, at which point they glide to the ground. “Sometimes it takes a few shots, which are really loud,” Youngentob said, “And they're just sitting there and looking at you as if to say, 'What are you doing?'”
Variation in their extraordinary tails was one of the features that alerted Jackson to the species divisions. Youngentob told IFLScience their tails are not used to grip branches but to act as a counterweight while sitting and as a rudder while gliding. In the mating season, gliders frequently like to sit together with their tails wrapped around each other, a fact that might go some way towards achieving Youngentob's goal of building public pressure to save them. “They've played second fiddle to koalas for too long,” she said.
As a part of her Ph.D. project to understand why greater gliders varied so much across their range, Ms McGregor discovered that the genetic differences between the populations she was looking at were profound.
“There has been speculation for a while that there was more than one species of greater glider, but now we have proof from the DNA. It changes the whole way we think about them,” she said.
“Australia's biodiversity just got a lot richer. It's not every day that new mammals are confirmed, let alone two new mammals,” Professor Krockenberger said.
“Differences in size and physiology gave us hints that the one accepted species was actually three. For the first time, we were able to use Diversity Arrays (DArT) sequencing to provide genetic support for multiple species.”
Greater gliders, much larger than the more well-known sugar gliders, eat only eucalyptus leaves and live in forests along the Great Dividing Range from northern Queensland to southern Victoria. Once common, they are now listed as “vulnerable,” with their numbers declining.
“This year Australia experienced a bushfire season of unprecedented severity, resulting in widespread habitat loss and mortality. As a result, there's been an increased focus on understanding genetic diversity and structure of species to protect resilience in the face of climate change,” she said.
“The division of the greater glider into multiple species reduces the previous widespread distribution of the original species, further increasing conservation concern for that animal and highlighting the lack of information about the other greater glider species.”
The koalas were the face of the international headlines during the climate calamity of the 2019 -2020 Australian mega-bushfires. Horrific images of severely burned and dead mammals made them the face of international news coverage and spotlighted the dangers of increasing heat, drought, and bushfires. Other marsupials, including greater gliders, suffered the same fate and in the case of Greater Gliders, lost one-third of their habitat. Eucalyptus trees are heavy with oil and sap and explode into flames easily during bush fires. catapulting embers into the sky and igniting new fires many miles away.
Logging is a major force destroying critical habitat, these forests are 200 years old and it would take over 120 years to provide homes to wildlife once again. One hundred and twenty years that glider populations do not have in order to prevent extinction.