Call of an elusive toadlet finally recorded after 43 years

The call of an inconspicuous desert-dwelling frog has been recorded for the first time since the species was first discovered in 1981.

A call of the Tanami Toadlet (Uperoleia micromeles) was captured by ecologists at Australian Wildlife Conservancy’s (AWC) Newhaven Wildlife Sanctuary, about 350km north-west of Alice Springs.

The tiny frogs grow to just 4cm and are commonly known as toadlets due to their bumpy skin, though they are not closely related to toads.

The sound was recorded in March, a week after record-breaking rains inundated Central Australia. Newhaven recorded more than 316mm over the month, triggering a boom of plant and animal activity.

Recording of a Tanami Toadlet call captured at Newhaven Wildlife Sanctuary. Credit: Tim Henderson/Australian Wildlife Conservancy

So, why did it take more than 4 decades to record the call of this species?

AWC Senior Science Communicator Joey Clarke told Cosmos there hasn’t been a huge amount of scientific attention paid to frogs in Australia’s arid zone.

“Partly that’s because of their lifestyle, which typically involves very long periods where they are either underground or hiding out in little pockets of moisture in between rainfall events.

“During periods between rain, the Tanami Toadlet has been recorded more than a metre deep in the sand, where it is able to remain in a low metabolic state (called aestivation) until the next rain event.

“This species has also been recorded living in the burrows of larger Desert Spadefoot frogs – essentially a commensal burrow-sharing arrangement.”

A photograph of a small lake filled with water. The water is reflecting the sky, which contains blue-grey clouds at sunset.
Newhaven Wildlife Sanctuary’s landscape replenished by recent rainfall. Credit: Aliesha Dodson/Australian Wildlife Conservancy

When it does finally rain, Clarke says you have to be in the right place at the right time.

“This species is found in desert parts of central and Western Australia, places with very low population density which become inaccessible after heavy rain.

“Because AWC has a permanent research station at Newhaven, our team is in this privileged position with front-row seats to these rainfall events and the ‘boom’ conditions.”

Dr Tim Henderson, an AWC wildlife ecologist, says: “We visited one of the claypan lakes to look for frogs and see if we could track down the Tanami Toadlet.

“The lake is full at the moment, and while we were there, we heard lots of frogs calling. The calls were really distinctive, and unlike any of the other species that we find out here regularly.

“We were eventually able to pinpoint the calls through the undergrowth to locate these little frogs, which matched the description for Tanami Toadlets.” 

A photograph of 3 people dressed in casual active clothing. They are wading through knee-deep brown water in a lake, surrounded by partially submerged trees.
Ecologists walk through a water-filled lake after the rain at Newhaven Wildlife Sanctuary. Credit: Aliesha Dodson/Australian Wildlife Conservancy

The recording was made using the FrogID app developed by the Australian Museum and will make it easier to detect this species in the future.

Clarke says: “…the availability of the FrogID app means that all of us are now walking around with sound recording devices in our pocket, which we can whip out when we hear something interesting.”

The rest of us can also listen out for their calls, from the western side of the Northern Territory to the coast of the Pilbara in Western Australia, near standing waterbodies after rain.

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