Environment and Resource Management

Sharp-snouted dayfrog

Sharp snouted dayfrog. Photo: SJ Richards

Sharp snouted dayfrog. Photo: SJ Richards

Common name: sharp-snouted dayfrog

Scientific name: Taudactylus acutirostris (Andersson, 1916)

Family: Myobatrachidae (Australian water frogs)

Conservation status: This species is listed as Endangered in Queensland (Nature Conservation Act 1992) and Extinct 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

A small frog with narrow wedge shaped snout, males 18-25 mm and females 22-31 mm long. Adult males weigh up to 1.6g and females 2.5g (McDonald and Alford 1999). Dorsum greyish olive - dark chocolate brown, may have dark V or W shaped markings. Broad, dark grey or black band, bounded above by distinct pale line, runs laterally from the level of the eye to groin.

Hind legs have darker cross bands, sometimes barely detectable, but usually quite conspicuous. The ventral surface is greyish white with dark flecks and blotches. Rear part of ventral surface and underside of the limbs are olive-yellow. Distinct white patch edged with black at base of each forelimb. Lower jaw edged with black. Skin is smooth above and below, with tubercles arranged in a triangle or ridges on lower back, and there's a distinct dorso-lateral skin fold. Fingers and toes have slightly expanded toe pads, and are fringed but lack webbing (Liem & Hosmer 1973, Dennis 1982, Cogger 2000).

Habitat and distribution

Sharp snouted dayfrogs are generally found among rocks and leaf litter along the edges of rainforest streams, though in wet weather they may be found some distance from the water (K.R. McDonald pers. obs.).  It is a diurnal species often basking in the sun. The tadpoles are lotic benthic normally inhabit debris in pools or slow flowing areas of rainforest streams (McDonald and Alford 1999, K.R. McDonald pers. obs.).

The sharp snouted dayfrog was widely distributed through the upland rainforests of the Wet Tropics, from Mt. Graham near Cardwell to Big Tableland approximately 30km south of Cooktown. This distribution was Latitude: Between 15&186; 42' and 18&186; 24' and Longitude: Between 145&186; 2' and 145&186; 57'. The species underwent a dramatic range contraction in the late 1980's, to the northern boundary of its distribution. The last sighting occurred at Big Tableland in January 1995. An individual has been reported from Mount Father Clancy, South Johnstone R (Marshall 1998) but additional surveys have not located the species.

National Parks: Cedar Bay, Daintree, Wooroonooran, Mt Hypipamee, Tully Falls, Lumholtz.

Life history and behaviour

The sharp snouted dayfrog appears to have two calls. A high pitched metallic tinkling sound, "tink tink", repeated several times in quick succession (Liem & Hosmer 1973, Dennis 1982, Richards 1993), and a second call variously described as a popping call (McDonald 1992) or a short, scratchy chirp, "eek eek eek" (Ingram 1980, Richards et al 1993). Males call from exposed positions on rocks, sand or gravel banks at the waters edge, or from beneath rocks or leaves (Ingram 1980, K.R. McDonald pers. obs.). They call from first light, and may continue until early evening. The males establish territories (Dennis 1982). After a period of basking, individuals will move off to forage along the sides of creeks and the rainforest floor nearby. When disturbed they will leap into the water, and lie on the substrate for some minutes before resurfacing (Ingram 1980).

Calling males and gravid females have been encountered year round (McDonald and Martin unpublished data). Females lay 25-40 large (2.2-2.7mm diameter) unpigmented eggs in a large gelatinous clump on the underside of rocks at or below the waterline in flowing creeks (Liem and Hosmer 1973).

Tadpoles are small, with a dark oval body, transparent and unpigmented posteriorly with discrete spots across tail muscle and fins. Eyes are on top of the head. They have two rows of teeth anterior to the jaws and three posterior to the jaws. The inner two rows of teeth are divided in the middle (Liem & Hosmer 1973, Richards 1993).

Threatening processes

The sharp snouted dayfrog is one of seven species of frogs occurring in the upland rainforest streams of north-eastern Queensland which have undergone rapid and substantial population declines (Ingram and McDonald 1993, Richards et al 1993, Trenerry et al 1994), with only three individuals reported from the wild since December 1994.

The causes of the decline remain unknown, Richards et al (1993) found no obvious evidence that drought, floods, habitat destruction or pollution by pesticides, inorganic ions or heavy metals were responsible for the population declines. 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 can be located at the James Cook University website. UV impact has been discounted in the tropics (McDonald and Alford 1999).

Recovery actions

The recovery plan (PDF)* makes the following management recommendations for the conservation of stream-dwelling frogs of the Wet Tropics bioregion.

Related information

Cogger, HG 2000. Reptiles and Amphibians of Australia. Reed New Holland, Sydney.

Hero, J-M and Fickling, S 1994. A Guide to Stream-dwelling Frogs of the Wet Tropics Rainforests. James Cook University of North Queensland, Townsville.

Tyler, MJ 1997. The Action Plan for Australian Frogs, Environment Australia, Canberra.

Tyler, MJ and Knight, F 2009. Field guide to the frogs of Australia. CSIRO Publishing, Collingwood Victoria.

References

Berger, L, Speare, R, and Hyatt, A 1999. Chytrid fungi and Amphibian declines: Overview, Implications and Future Directions. Pp23-33. In Campbell, A (ed), 'Declines and Disappearances of Australian frogs'. Environment Australia, Department of the Environment and Heritage: Canberra. 234 pp.

Cogger, HG 2000. Reptiles and Amphibians of Australia. Reed New Holland, Sydney.

Dennis, A 1982. A brief study of the Sharp-snouted Torrent Frog Taudactylus acutirostris. North Queensland Naturalist 50: 7-8.

Ingram, G 1980. A new frog for the genus Taudactylus (Myobatrachidae) from mid-eastern Qld with notes on the other species of the genus. Memoirs of the Qld. Museum. 20(1):111-119.

Ingram, GJ and McDonald, KR 1993. An update on the decline of Queensland's frogs. Pp 297-303 In Lunney, D and Ayers, D (eds), 'Herpetology in Australia. A diverse discipline'. (Royal Zoological Society of New South Wales: Mosman). 414pp.

Liem, DS and Hosmer, W 1973. Frogs of the genus Taudactylus with description of two new species (Anura: Leptodactylidae). Memoirs of the Queensland Museum 16(3): 435-457.

Marshall, CJ 1998. The reappearance of Taudactylus (Anura: Myobatrachidae) in north Queensland streams. Pacific Conservation Biology 4:39-41.,

McDonald, KR 1992. Distribution patterns and conservation status of north Queensland rainforest frogs. Conservation Technical Report 1., Queensland Department of Environment and Heritage, Brisbane.

McDonald, KR, and Alford, RA 1999. A Review of Declining Frogs in Northern Queensland. Pp14-22. In Campbell, A (ed), 'Declines and Disappearances of Australian frogs'.(Environment Australia, Department of the Environment and Heritage: Canberra). 234 pp.

Richards, SJ, McDonald, KR, Alford, RA 1993. Declines in populations of Australia's endemic tropical rainforest frogs. Pacific Conservation Biology 1:66-77.

Trenerry, MP, Laurance, WF, and McDonald, KR 1994. Further evidence for the precipitous decline of endemic rainforest frogs in tropical Australia. Pacific Conservation Biology 1: 150-153.

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Last updated 26 July 2011

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