King of the Sandstone Throne: The red crowned toadlet

This species of the week is dedicated to the threatened red crowned toadlet (Pseudophryne australis) which is both spectacularly adorable and has an incredibly interesting strategy of survival. This frog is quite small and is really strange for a frog in the way it lives. The red crowned toadlet, unlike most frogs, makes a terrestrial nest. The male will sit and guide his egg clutch and call almost all year round. Female red crowned toadlets visit the male and deposit eggs which he fertilises. The tadpoles start development inside the egg. A male will end up with eggs of many different stages of development stages. When it rains, the eggs in the nest will wash away to the closest puddle or creek where the developed tadpoles will emerge from their eggs to complete development as free swimming tadpole. Only the eggs at the right development stage will be able to survive when being washed into a puddle.  By having eggs of multiple development stages, the red crowned toadlet is able to ensure at least some of the eggs will be at the correct development stage when it rains and will hatch. This is the unique strategy of the red crowned toadlet known as ‘bet hedging’.

 

Copyright Chad Beranek (2014)

Copyright Chad Beranek (2014)

 

The red crowned toadlet is found in sandstone areas across Sydney and is quite well distributed within the Royal National Park. They prefer rocky sandstone outcrops and reside within tributaries that are prone to drying up. This is the perfect habitat for their unique life strategy. They are threatened due to being easily wiped out during development and may be susceptible to the changes to water run off due to curb and guttering, which diverts water away from the small tributaries that the red crowned toadlets live in.   With good management, this species can be preserved and hopefully they will continue to exist unimpeded in areas such as the Royal National Park as they are an interesting little frog.

 

A male Red Crowned Toadlet next to his nest of eggs | Copyright Lucy Kidson (2014)

A male Red Crowned Toadlet next to his nest of eggs | Copyright Lucy Kidson (2014)

 

One last random fact sure to interest most people is you can actually talk to them and they will call back. They are able to hear the frequency of the human voice, and if you yell for example “HEY FROG!?”, it will respond in its calls which is a series of squelches and squeaks.

 

Male Red Crowned Toadlet | Copyright Lucy Kidson (2014)

Male Red Crowned Toadlet | Copyright Lucy Kidson (2014)