A tiny frog with tusks rediscovered on the New England Tablelands and North West Slopes of eastern Australia

All is not lost for an endangered population of frogs – the Tusked frog (Adelotus brevis) of the New England Tablelands and Nandewar bioregions has been rediscovered after fears of their extinction.

A small but remarkable frog, the Tusked Frog (Adelotus brevis), is named after their pointed “tusks” on their lower jaw. Although a dull brownish colour on top, they have brilliant red or orange flashes on their legs and a marbled black and white belly. Males of the species have much larger heads and bigger tusks than females, and they use the tusks to fight with other males in defense of breeding sites. They’re not your average frog!

The Tusked Frog is distributed along the east coast of Australia, from the central coast of Queensland, to just north of Sydney in New South Wales (NSW). The species was once widespread throughout the vast New England Tablelands and the Nandewar regions (North West Slopes) of NSW. However, the species appeared to vanish from the region sometime after the 1970s. As a result of these declines, the Tusked Frog on the New England Tablelands and Nandewar regions was deemed “in immediate danger of extinction” and formally named an endangered population in 2001.

Not coincidentally, this was the same time that other frog species in the region disappeared or suffered dramatic population declines. The Peppered Tree Frog (Litoria piperata) and the Yellow-spotted Bell Frog (Litoria castanea) are missing and are feared to be extinct. Only a single population of the Booroolong Frog (Litoria booroolongensis) has recently been rediscovered from the New England Tablelands. The likely reason for these simultaneous disappearances was a disease caused by the amphibian chytrid fungus. This same disease is responsible for amphibian population declines and disappearances around the world.

The last records of the endangered population of the Tusked Frog were in the late 1990s and mid-2000s. Surveys across the former range of the endangered population over recent years have failed to detect the species, and scientists were fearing the worst.

However, during this summer (2020-2021), the distinctive ‘chirrup’ call of the species was again heard west of Tenterfield in the Mole River area of northern NSW, and recorded with the Australian Museum's FrogID app. This is an area where the species hadn’t been reported for over 40 years, and for now, this site represents the only known location of this endangered population of Tusked Frogs.

In this quiet bend of a river, it appears that conditions were just right so as to provide refuge for a small tusked frog. An important part of our natural history, previously feared extinct on the New England Tablelands and Nandewar regions, is not lost. The faint ‘chirrups’ of the Tusked Frog still carry through the night air in at least one valley in the region, and we have an opportunity to ensure that it continues to do so for generations to come.

Help survey your local frogs: FrogID

This rediscovery also highlights just how much we still have to learn about our frogs. By simply downloading the Australian Museum's free FrogID app and recording the calls of your local frogs, you can help better understand and conserve frogs like the Tusked Frog.

If you live in the New England Tablelands or Nandewar regions, please do listen out for the Tusked Frog (listen here).

FrogID on ABC Landline

Watch an ABC Landline segment on FrogID: Finding Frogs: The project to find Australia's frogs.

Dr Jodi Rowley, Curator, Amphibian & Reptile Conservation Biology, Australian Museum Research Institute & UNSW Sydney.