The Tasmanian tiger, also known as the thylacine, once populated much of Tasmanian and mainland Australia—where it is also still searched for—but few know that the animal was present on New Guinea as well. Its prehistoric presence there first came to light in 1960 when archaeologists discovered the lower jaw of a Tasmanian tiger.

"Further confirmed fossil remains, dating at over two million years old, have subsequently been found on New Guinea; and also in later years, unconfirmed sightings of thylacine-like beasts have been reported from both PNG and Irian Jaya," Shuker told mongabay.com.

While Tasmanian tigers are believed to have died out in New Guinea at the end of the Pleistocene, Shuker believes there's a chance a population still survives on the mountainous island, which contains some of the world's least-explored terrestrial habitats.

"New Guinea, especially Irian Jaya, is far less well-explored than either Tasmania or mainland Australia, as confirmed for instance by recent expeditions to Irian Jaya's Foja Mountains, where several new and potentially new species were discovered, including a giant rat, a tiny wallaby, and a new honeyeater," Shuker says.

"Consequently, there is a much greater chance of zoological novelties turning up here than elsewhere within the thylacine's former distribution range, and one such novelty may be the thylacine itself."

In fact, curious stories have filtered out of New Guinea in recent years. In Irian Jaya, some tribal groups talk of a local canine-like animal known locally as the dobsegna.

According to Shuker, descriptions of the animal—not yet confirmed or identified by scientists—track closely to the Tasmanian tiger, including a massive mouth (notably, Tasmanian tigers could open their mouths up to 120 degrees) and a long straight tail.

In addition, Shuker says he does not believe the dobsegna refers to another wild canine on the island: the New Guinea singing dog.

"The singing dog is not striped (unlike the mysterious dobsegna and the thylacine), and does not have a stiffened tail (which the dobsegna does, just like the thylacine). Moreover, native tribes are very familiar with the singing dog, which they have hunted for food in the past when it was still common, whereas they seem much more wary and even frightened of the dobsegna," explains Shuker.

However, so far these reports, however tantalizing, remain just that: hear-say. No one has yet brought back proof, such as photos, videos, samples, or the Holy Grail of crypto-zoologists: a living animal.

Shuker says the next step is to "send out dedicated expeditions to Irian Jaya and PNG in search of [the Tasmanian tiger], or in search of preserved relics of it in native villages." Some possible starting places: the forests around Mount Giluwe in the Southern Highlands and those surrounding Puncak Jaya in Indonesian New Guinea.

If the Tasmanian tiger still resides in the wilds of New Guinea—and it's a big if—the find would certainly be among the most amazing zoological discoveries of the last hundred years. In addition, whatever scientists or adventurers uncovered it would be immortalized in the annals of science.

Of course, that's assuming that thousands of years after its presumed local extinction, the Tasmanian tiger—that wide-mouthed, tiger-striped, marsupial predator—still haunts the night forests of New Guinea.