Adelaide University, Media Release, 16 February 2026
A tiny, threatened marsupial not known to have inhabited South Australia’s Yorke Peninsula may exist as a relict population and still be clinging to survival, according to new research that has re-examined historical field data from one of the region’s most important conservation areas.
In a study published in Australian Zoologist, researchers report compelling evidence that the Little Pygmy-Possum (Cercartetus lepidus) may exist in Dhilba Guuranda–Innes National Park, more than 200 kilometres west of its nearest known population on Kangaroo Island.
The finding is based on a recent review of photographs taken during pitfall trapping surveys conducted between 2004 and 2011. Among hundreds of captures of the closely related Western Pygmy-Possum, two animals photographed in December 2006 stood out as different.
The Little Pygmy-Possum has distinctive grey ventral fur, unlike the white ventral fur of the Western Pygmy-Possums.
“There is no museum or other record of Little Pygmy-Possums for the Yorke Peninsula,” said lead author Dr Sophie (Topa) Petit, from Adelaide University’s School of Biological Sciences.
“Although the animals looked slightly different from Western Pygmy-Possums, they were labelled as juveniles, because no one in the team expected to discover a new mammal species for the Yorke Peninsula.”
The Little Pygmy-Possum is one of Australia’s smallest mammals, weighing just a few grams and feeding on nectar, pollen and insects. It is currently known to exist only in Tasmania, western Victoria, south-east South Australia and on Kangaroo Island. It has never been confirmed on the Yorke Peninsula, and no remains have been found in the region’s subfossil deposits.
If verified through new surveys, the Yorke Peninsula population would represent a previously undiscovered relict population, potentially isolated for thousands of years since rising sea levels separated Kangaroo Island from the mainland.
The discovery is especially significant given the extensive loss of native vegetation on the Yorke Peninsula, where only about 13 per cent of original habitat remains. More than half of that is concentrated in the southern tip of the peninsula, within Dhilba Guuranda–Innes National Park.
“This area is an important refuge for what’s left of the region’s native fauna,” Dr Petit said. “If the Little Pygmy-Possum is still there, it needs urgent attention.”
The study raises concerns about the impacts of habitat fragmentation and repeated prescribed burning, which has occurred frequently in the area since the possums were photographed.
Very little is known about how the Little Pygmy-Possum responds to fire, but evidence from other regions suggests it is less resilient to disturbance than its larger relative.
“It’s possible that this population has become extinct in the last 20 years, considering its rarity,” Dr Petit said.
“But it would be wonderful to discover it has survived. Adopting a precautionary approach to land management until the species’ status is verified would be the best course of action.”
‘Is the Little Pygmy-Possum Cercartetus lepidus extant on the Yorke Peninsula of South Australia?” is published in the Australian Zoologist. DOI: 10.1071/AZ25053.
