A Cool(oola) frog

Picture this - you've been tramping through hot and sticky Queensland rainforest on a summer's night, climbing up and down the sandy dune substrate. Suddenly, the path leads you out into a large open space, the moon illuminates the scene before you. You see virgin white sand ringing a large lake, Melaleuca trees scattered here and there on the banks, reeds emerging from the shallows. The sound-scape is equally rich; the frogs are out in force tonight. You hear the yapping of two types of rocket frog: the fast call of the slender and streamlined Litoria nasuta and the slightly slower call of the Wallum Rocket frog Litoria freycineti. There's another call at a higher frequency, sounding something like the squeak of a reluctant cork coming out of a bottle.

It's the species that is producing this noise that was so exciting to me on that night in December a couple of years ago. It's the Cooloola Sedge Frog, Litoria cooloolensis. Fitting name, considering Cooloola was the setting; it's just south of Fraser Island and has the same sort of environment as is found on that sandy isle. A lot of that area, between the dunes, is 'wallum', which is a type of boggy heathy environment often with Melaleuca; it's a habitat that occurs only in south-east Queensland and north-east NSW. These freshwater lakes are another great feature of the area, perfect for a moonlit swim.


So, to the frog! It's one of the most beautiful little treefrogs in my opinion. Quite similar to the Dwarf Treefrog Litoria fallax in size (~25mm), shape and call, though the green dorsum is finely speckled with black, and a quite obvious yellow is present on the flanks and legs. The flash colouration of this species is lovely - the thighs show a purple and an orange streak, and the armpit may have a bit of reddish orange too.

Revisiting the lake in the daylight, some of the frogs were basking on the emergent reeds. Like the one in the photo on the right, they would rest vertically on the stems and shuffle around the reed to stay on the opposite side to me!

Though on that night at that lake, the species was abundant, it's future may not be secure. IUCN lists this species as endangered:

"Listed as Endangered because its extent of occurrence is less than 5,000 km², its distribution is severely fragmented, and there is continuing decline in the extent and quality of its habitat in southeastern Queensland."

References:
Hines, H., Meyer, E., Hero, J.-M., Newell, D. & Clarke, J. 2004. Litoria cooloolensis. In: IUCN 2006. 2006 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Downloaded on 05 July 2006.

Litoria cooloolensis on the Frogs Australia network