Common mistfrog
Common name: common mistfrog
Scientific name: Litoria rheocola
Family: Hylidae (tree frogs)
Conservation status: This species is listed as Endangered in Queensland (Nature Conservation Act 1992) and nationally (Environment Protection and Biodiversity Conservation Act 1999). It is considered a low priority under the Department of Environment and Resource Management Back on Track species prioritisation framework.
Description
Size (SVL): males 27-36.4 mm, females 28.4-41.2 mm (McDonald and Alford 1999). Weight: males 1.2-3.3 g, females 1.8- 4.55 g (McDonald and Alford 1999).
The common mistfrog is a moderately sized frog. The frogs back surface is dull grey or brown, with irregular darker markings. There is a distinct inverted triangle marking on the top of the head, stretching between the eyes down to the lower back. An obscure darker band runs along the side of the snout, through the eye and ear to the shoulder.
The skin is smooth above, with scattered small tubercles. The under-belly is granular and white in colour. The finger and toe discs are large. The fingers are moderately webbed, and the toes nearly fully webbed. The tympanum (ear) is small and covered by skin, though the rim may be distinct. The male nuptial pads are small, with fine dark spicules. The tip of the snout is bluntly pointed (Cogger 2000, Liem 1974).
Tadpoles have flattened, sandy coloured body, which is darker underneath. The tail is very muscular, creamy yellow lightly dusted with diffuse dark pigment. The tail fins are clear, with only a few scattered pigments confined to small aggregations. The mouth acts like a sucker cap and is surrounded by fleshy growths (papillae). There are two anterior and three posterior tooth rows (Richards 1992).
Habitat and distribution
The common mistfrog is usually found on rocks and vegetation near fast-flowing streams in rainforest from 0-1180 m. Tadpoles are found in swiftly flowing rainforest streams, clinging to rocks in riffles, torrents, and highly oxygenated pools (Liem 1974).
This species occurred in rainforests north of the Herbert River in the Wet Tropics from Lumholtz National Park to Amos Bay, but has now disappeared from most sites above 400 m. Lowland populations remain secure.
Life history and behaviour
The call is a regular, repeated long drawn single note call, a rather nasal "wreek wreek wreek" (Liem 1974, McDonald 1992). Calling males and gravid females are found throughout the year (McDonald and Martin unpubl. data), and breeding has been observed during most months (Dennis and Trenerry 1984, Liem 1974). Large (1.4-1.8 mm diameter) unpigmented eggs are deposited in a compact gelatinous clump under rocks in fast-flowing streams (Liem 1974).
The tadpoles graze on algae-covered rocks in fast-flowing waters (Liem 1974).
Threatening processes
The causes of the decline of this species remain unknown. No obvious evidence has been found to suggest that drought, floods, habitat destruction or pollution by pesticides, inorganic ions or heavy metals are responsible for the population declines (Richards et al 1993). Current research is examining the possibility that a disease may have caused the decline of this species (Berger et al 1999). Information on disease investigations and management is located on the James Cook University website.
The common mistfrog is one of 7 species of frogs occurring in the upland rainforest streams of north-eastern Queensland which have undergone rapid and substantial population declines in the last decade (Ingram and McDonald 1993, Richards et al 1993, Trennery et al 1994). Declines were first noted in 1989 (Richards et al 1993), and have progressed northward, affecting the northern-most site in 1994 (Ingram and McDonald 1993, McDonald and Martin 1995). The species is still common at lowland sites, but has declined at most sites above 400 m.
Recovery actions
A recovery plan has been developed that relates to this species, the Recovery plan for the stream-dwelling rainforest frogs of the Wet Tropics biogeographic region of north-east Queensland 2000-2004. This recovery plan makes the following management recommendations for the conservation of stream-dwelling frogs of the Wet Tropics bioregion.
- Monitor historical localities to detect recovery.
- Investigate disease in preserved animals and species occupying similar habitat.
- Develop and refine husbandry techniques for rainforest stream dwelling frogs.
- Continue studies on the ecology of this species.
- Train park staff and community volunteers in identification of this species.
- Implement monitoring by park staff of select locations within the national park estate where the common mistfrog formerly occurred.
Last updated 24 November 2011