VICTORIA'S NEWEST FROG:
The Booroolong Frog
In early 1999, Victoria added another species to its list of frogs found in the state - the Booroolong Frog, Litoria booroolongensis, previously known only from New South Wales. This article is based on the report written by Graeme Gillespie (whose work led to the discovery) which was published in "In the Spotlight" (Vol 5, May 1999).
The Booroolong Frog was known to occur predominantly along western-flowing streams of the Great Dividing Range in New South Wales, from catchments draining the Northern Tablelands, to the Tumut River in the Southern Highlands, and other tributaries of the Murrumbidgee River. The Booroolong Frog had been recorded close to the north-eastern Victorian border east of the Hume Reservoir, but previous fauna surveys had not located it in Victoria.
In January 1999, Booroolong Frogs were located along three small creeks, several kilometres north of the Murray River, near Jingellic, NSW. This led to the suspicion that Booroolong Frogs may also occur along similar creeks feeding the Murray River from Victoria, north of Burrowa Pine Mountain. A subsequent survey was undertaken, searching four creeks (Burrowye, Walwa, Sandy, and Cudgewa Creeks) and the Murray River in this area. Booroolong Frogs were found on Burrowye Creek at Burrowye (lat 36°2'; long 147°33'), and on the banks of the Murray River near Jingellic (lat 35°56'; long 147°42'), confirming the occurrence of the species in Victoria.
Observations in southern NSW suggest that the Booroolong Frog and Lesueur's Frog (Litoria lesueuri) have allopathic distributions in this region (meaning the Booroolong Frog is not found where Lesueur's Frog is, and vice versa). Lesueur's Frog was found along Cudgewa Creek, and previous survey in the region have located L.lesueuri on most other streams in this region of Victoria. Therefore, the Booroolong Frog is likely to be restricted in Victoria to this region north of Burrowa Pine Mountain.
The Booroolongensis Frog inhabits rocky permanent streams, ranging from small slow-flowing creeks to large rivers. Adults are typically found sheltering under boulders or cobbles near riffles along the stream bank. The species occurs along stream in both forested areas and open pasture. In the southern parts of its range, breeding occurs in spring. Eggs are deposited in rock crevices in the stream or in isolated stream-side pools. Tadpoles metamorphose in January and February.
The Booroolong Frog is morphologically very similar to Lesueur's Frog (Litoria lesueuri) which is a common and widespread riverine species in south-eastern Australia.
L.booroolongensis may be reliably distinguished by the extension of the webbing, to the base of the first inner toe pad, on the hind foot. The webbing on Lesueur's Frog extends only to the base of the first inner toe (author's personal observation). The Booroolong Frog typically has a mottled dorsum with a scattering of salmon-coloured flecks. Lesueur's Frog typically has a distinct black stripe passing through the eye and over the tympanum to the shoulder, whereas this is less distinct in the Booroolongensis Frog.
The Booroolongensis Frog is one of a number of riverine species in eastern Australia which have suffered severe population declines over the past two decades. Booroolong Frogs were formerly abundant along streams draining the Northern Tablelands of New South Wales. There have been very few sightings of this species in the past ten years and concerns have been raised about its current conservation status. The species has recently been listed as endangered in New South Wales (NSW Threatened Species Conservation Act 1995). Its discovery in Victoria is a significant addition to the frog fauna of the State.
Now, of course, the site needs updating to accommodate this latest discovery. Hopefully, I will soon obtain a photograph of the frog that I can use as well as the mating call. After that I need to cobble together a page for the field guide information and add an extra question in the identification key. Coming soon (in that VFG kind of way).