The southern day frog was a small frog that measured 30mm. The skin on its back was grey or brown in colour, and varied from being smooth to granular, or possessing a few low warts. Its belly was always smooth with either a cream or a bluish colouration. There was a pale bar between the eyes, with a dark brown bar behind this pale one. A light stripe ran from the eye to the arm, while a dark H-shaped mark was present on the back. Individuals also possessed dark banding on the arms and legs.
This species was limited to disjointed populations inhabiting three sub-coastal mountain ranges in southeast Queensland - the Blackall, Conondale and D’Aguilar ranges - between Gibber Creek in the North and Mount Glorious in the south. Here, the species was found in montane rainforests and tall open forests. This species preferred to occupy clear, cool, permanent streams, and could also be found in temporary streams after heavy rain and on dry land within 10m of a waterway. Individuals were found in fast-flowing streams and could cling on to the underside of boulders to avoid danger or predation.
No information on the species’ population sizes, structure, genetics or dynamics is available, however it is known that individuals would mate during the summer months or after heavy rain. Fertilisation of the eggs was external, and the eggs were laid in clutches of 24-36 underneath rocks or branches in the water.
The southern day frog was first described in 1966. In the 1970s it was considered common, although the species was limited to disjointed populations inhabiting three sub-coastal mountain ranges in southeast Queensland. The disappearance of this species occurred over a period of 3 to 4 years, with the first populations disappearing in the D’Aguilar range in late 1975, then the Blackall Range in late 1978, and finally in the Conondale range where the last individual was seen in late 1979. Despite concerted efforts and repeated surveys of the area no individuals have been found since.
It is thought that the cause for the decline of the southern day frog was the same virulent disease which is the suspected cause of the extinction of the two species of gastric brooding frog. The southern day frog and southern gastric brooding frog disappeared from the same region within the same year, strengthening the theory that declines were most likely a result of an infection with the chytrid fungus (Batrachochytrium dendrobatidis). These are just two of many species which are thought to have been affected by a chytrid epidemic that spread through Australian Frog populations from the late 1970s until the early 1990s.