Ever flushed a toilet in the outback and seen a frog swirling around the bowl? These so-called 'dunny frogs', often found hiding in toilets, showers and water tanks, have long been considered a single species but new research has revealed they are actually three distinct species.
Dr Renee Catullo from The University of Western Australia, and researchers from museums in Queensland, New South Wales, South Australia, Western Australia and Germany, made the discovery in a study published in Zootaxa.
"A lot of people have come across these frogs in the outback, where they often turn up in wet areas like sinks and toilets," Dr Catullo said.
"When we look for them in the wild, we visit a lot of toilets and water tanks!"
Researchers analysed genome data, sequenced mitochondrial DNA, examined variations in body size and shape, and studied the males' mating calls.
They found male frogs in this group had a distinctive, strident mating call – a sustained, multi-pulsed bleating noise, somewhat like a seagull.
The red tree frog (Litoria rubella) was thought to be a single species with the largest distribution of any Australian frog – spanning 4.6 million square kilometres, from the monsoon tropics to the desert.
But researchers suspected that such a widespread species might actually be more than one.
Using genetic data, body measurements, and mating call analysis, the team identified two new species: the western desert tree frog (Litoria larisonans) found in the Pilbara and central arid zones in WA; and the ruddy tree frog (Litoria pyrina), which lives in tropical coastal areas of Queensland and New South Wales.
"These frogs are a great example of how species can adapt to extreme environments, from tropical coastlines to dry deserts," Dr Catullo said.
"Their abundance and diversity make them an important model for studying the evolution of Australian frogs."
So next time you hear an unusual croaking near an outback toilet, you might just be listening to one of Australia's newly discovered frog species.
