Field researchers call them “Lazarus taxa,” species once presumed extinct that suddenly appear to have risen from the dead. And scientists have found one more—a marsupial thought to have disappeared over 6,000 years ago.
Researchers with the Australian Museum and the University of Papua discovered this elusive marsupial—known as the pygmy long-fingered possum (Dactylonax kambuayai)—still doing its thing within the remote rainforests of Indonesia’s Vogelkop Peninsula on the island of New Guinea. But the pint-sized, tree-dwelling mammal had company: a previously unknown genus of marsupial gliders.
“Describing a new species is exciting enough. But identifying an entirely new genus is something else altogether,” the researchers wrote of their find in The Conversation.
Elders from the island’s Tambrauw and Maybrat clans, who have long known about these creatures, helped the team identify and name the new genus Tous, the local nickname for these forest gliders. Each of the high-flying gliders, including the newly minted ring-tailed glider species (Tous ayamaruensis), are evolutionary offshoots from a branch of the possum family tree that, like the pygmy long-fingered possum, was previously thought to be extinct. So, not quite “Lazarus taxa” themselves, but pretty darn close.
“The Vogelkop is an ancient piece of the Australian continent that has become incorporated into the island of New Guinea,” paleontologist Tim Flannery, an Australian Museum Distinguished Visiting Fellow and coauthor on the new study, explained in a press release. “Its forests may shelter yet more hidden relics of a past Australia.”
From extinct to extant
Flannery, who earned his PhD tracking the prehistoric evolution of kangaroos, had to resort to a piecemeal record of fossil fragments to confirm what rare photographs and acquired specimens of these species appeared to show. At least two of these specimens of the pygmy long-fingered possum had been, in fact, sitting around in fluid jars at the University of Papua New Guinea museum and misidentified for decades.
The pygmy long-fingered possum, D. kambuayai, is the smallest of this boldly striped family of possums. As its name suggests, it has one remarkably long digit on each hand, measuring twice the length of its next longest finger. These prodigious digits are believed to help it probe for deep wood-boring insect larvae, similar to some species of lemur.
Scientists had previously pegged the last-living example of D. kambuayai to a nearby dig site dating back to just after the Misox oscillation, a global rapid-cooling event (or a “not quite” Ice Age) precipitated by the mass melting of glaciers about 8,200 years ago. Paleontologists had previously found fragments of jawbone belonging to the pygmy long-fingered possum at Kria Cave and dated them to between 7,500 and 6,000 years old. Scientists had never encountered this creature in the flesh and reasonably assumed it was extinct.
The team published its findings on D. kambuayai in the journal Records of the Australian Museum on Friday.
Not extinct, not yet
As for the ring-tailed glider and its fellow Tous cousins, the researchers turned to their respective dental records. Flannery and his collaborators examined fossilized possum teeth from the region, as well as newer partially fossilized material from a different part of the Papua New Guinea island chain, comparing this evidence to photographs of what would prove to be the team’s newly identified genus of glider.
The 300-gram (11-ounce) creature, which looks like a squirrel mated with a chameleon, is suspected to live off a diet of “sap” and “some leaves.”
“Traditional knowledge indicates Tous roots in tree hollows in the tallest rainforest trees,” Flannery and his coauthors wrote in The Conversation. “Like Australia’s greater glider, it is vulnerable to logging.”
According to the Australian Museum, the Global Wildlife Fund is now working with local communities to protect the forests of the Vogelkop peninsula, which may prove to be the last remaining habitat for both these rediscovered and newly described possum species.
“We worked very carefully and collaboratively with Tambrauw Elders and identification would not have been possible without cooperation,” Rika Korain, a Maybrat woman and co-author on this research, said in a museum statement. “This connection has been essential for ongoing work.”
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