The Mahony’s toadlet (Uperoleia mahonyi) is the newest known amphibian in Australia following its discovery by University of Newcastle biologist Simon Clulow in Oyster Bay.

Dr Clulow said the frog’s unique marbled underbelly – or ventral pigment – told him instantly he was holding something unfamiliar to the world of science.

“The distinctive marble pattern on the frog’s belly… led us to believe straight away we had found a new species,” Dr Clulow said.

“It was an incredible moment.”

Not to be confused with a toad, the Mahony’s toadlet is a native Australian frog classified by the glands on its back, which resemble those of toads in Europe and the Americas.

Scarcely bigger than a human fingertip, the frog is thought to live in a select few coastal swamps in Port Stephens, the Myall Lakes and the Central Coast.

The species is thought to employ a blend of camouflage and flair to avoid detection and capture.

“They are highly secretive. Individuals remain well camouflaged and hidden under grass, leaves and sand and are often found only by following the male... mating call,” Dr Clulow said.

“If a predator comes across the frog, it will flash a brilliant burst of orange as it attempts to leap to safety. This is thought to momentarily startle the predator.”

Dr Clulow named the species after his mentor, renowned frog expert Professor Michael Mahony, and coauthored research on his discovery in the scientific journal Zootaxa.

He said modern discoveries of vertebrate species were exceptionally rare, especially near cities and towns. 

“Nowadays many new discoveries are based primarily on genetics, that is the frogs look similar to other known species but when we analyse them in the lab we find they differ genetically,” Dr Clulow said. 

“It’s almost unheard of to pick up a vertebrate in the field and know instantly, based on appearance alone, that it is a new species.”

The Mahony’s toadlet is a habitat specialist that lives exclusively on a particular type of leached white sand substrate, which its discoverer says could put it at risk from habitat loss and sand mining.