U.S. scientists from the Smithsonian Institution and colleagues say findings suggest the western long-beaked echidna, one of the world's five egg-laying species of mammal, survived in Australia much longer than previously thought and may still be living in remote areas of the island continent.
The only known population of the long-beaked species, on the Indonesian portion of the island of New Guinea, is small and declining and the species has been listed as endangered, they said.
Fossil remains show the creature lived in Australia tens of thousands of years ago but an analysis of a specimen in the collection of the Natural History Museum in London showed it was collected in the wild in northwestern Australia in 1901.
"Sometimes while working in museums, I find specimens that turn out to be previously undocumented species," Smithsonian researchers Kristofer Helgen said. "But in many ways, finding a specimen like this, of such an iconic animal, with such clear documentation from such an unexpected place, is even more exciting."
Four species of echidna and the platypus are the only living examples of monotremes, a small and primitive order of mammals that lay eggs rather than give birth to live young.
Discovering whether the western long-beaked echidna still exists in Australia today will take time, researchers said.
"The next step will be an expedition to search for this animal," Helgen said. "We'll need to look carefully in the right habitats to determine where it held on, and for how long, and if any are still out there.
"We hold out hope that somewhere in Australia, long-beaked echidnas still lay their eggs."