20.
Sharp-snouted Day frog
(Taudactylus acutirostris)
CR
Overview
With only three individuals reported since 1994, there is doubt as to whether this species is still surviving in the wild. The sharp-snouted day frog is just one species out of many in the region which have been affected by the chytrid fungus Batrachochytrium dendrobatidis. This disease, which was first identified in this species, is thought to have caused a series of frog population declines and extinctions across north-eastern Australia, including the extinction of the gastric brooding frogs in the genus Rheobatrachus, and has been implicated for amphibian declines in many parts of the world.
Urgent Conservation Actions
Surveys of former range to confirm this species' extinction; general research into the fungal disease chytridiomycosis.
Distribution
Northern Queensland, Australia.
Associated Blog Posts
1st May 12
With only three individuals reported since 1994, it is possible that the sharp-snouted day frog (Taudactylus acutirostris) is already extinct. This frog ...  Read

Evolutionary Distinctiveness
Order: Anura
Family: Myobatrachidae
The Myobatrachidae family arose during the early Cretaceous period around 100 million years ago, a time when dinosaurs dominated life on Earth. The family is distributed throughout Australia and southern New Guinea, and is split into 3 sub-families - the Limnodynastinae, Myobatrachinae and Rheobatrachinae. The Myobatrachidae is notable among amphibian groups because most of the species exhibit some form of parental care, including gastric brooding, and the carrying of tadpoles in pouches, similar to marsupial mammals.

The genus Taudactylus, known as torrent frogs, contains just six species, and is highly threatened with extinction; four of the species have been classified by the IUCN as Critically Endangered, one as Near Threatened, and one as Extinct. The sharp-snouted day frog is listed as Critically Endangered, but is actually possibly extinct. Further research is urgently required to determine the status of this species - we can only hope that it has not already disappeared like its close relation, the southern day frog.
Description
The sharp-snouted day frog is the most distinctive member of its genus to look at. It is a small frog with a narrow wedge-shaped snout that is acutely pointed and protrudes well beyond the lower jaw. Its back is greyish-olive to dark chocolate brown and may have dark V- or W-shaped markings. A broad dark grey or black band, bounded above by a distinct pale line, runs along each side of the frog at eye level, from the tip of the snout to the groin, and the lower jaw is edged with black. The hind legs have dark cross bands, sometimes very faint but usually quite conspicuous. The frog’s lower surface is greyish-white with dark flecks and blotches, while the upper rear potion of the frog and the undersides of the limbs are olive-yellow. There is a distinct white patch edged with black at the base of each forelimb. The skin is smooth above and below, with tubercles (or small, raised bumps) arranged in a triangle or ridges on lower back. Fingers and toes have slightly expanded toe pads or discs, and are fringed but lack webbing. Males measure 22-27mm from snout to rear, with females slightly larger at 29-30mm.

Tadpoles are small, with rounded snouts and oval-shaped bodies which, although mostly dark, are transparent at the back end which allows some of the internal organs to be seen. The tail fins are pigmented, and the tip is rounded.
Ecology
Breeding takes place throughout the year, when females lay 25 to 40 large unpigmented eggs (up to 2.7 mm diameter) in clumps positioned on the base of rocks on or below the waterline in shaded parts of streams. On hatching, tadpoles live in pools or slow flowing sections of the stream, where they spend most of their time among debris.

Males call from open areas such as rocks or gravel banks, or from the base of streamside vegetation. There appears to be two different types of call, one likened to a metallic tinkling, repeated a number of times in quick succession, and the other more like a chirp. Males seem to form territories, although this may be a response to the dramatic population declines, and resultant low numbers of females. Disturbed individuals quickly jump into the water, where they remain sat on the bottom for some time before resuming basking or foraging on the stream bank.
Habitat
The sharp-snouted day frog is generally found among rocks and leaf litter along the edges of fast-flowing rainforest stream, although in wet weather they may be found some distance from the water. This is a diurnal (or day-active) species, which will often bask in the sun. The tadpoles tend to dwell at the bottom of water bodies, inhabiting debris in pools or slow flowing areas of rainforest streams.
Distribution
The sharp-snouted day frog is an Australian endemic which has declined from the majority of its former range in northern Queensland. The species underwent a dramatic decline in its occupied range in the late 1980s, remaining only in the northern boundary of its distribution, with the last few sightings in Big Tableland, 30km south of Cooktown in 1995, in a small tributary of the South Johnstone River in 1996, and finally near Mount Hartley in 1997. This frog has been found at altitudes of 300-1,300 metres above sea level, but since all recent surveys have failed to local any individuals, it is increasingly feared that this species may already be extinct.
Population Estimate
Historically an abundant species, recent surveys of suitable habitat within the known range of this species have found no individuals. It is possible that this species is now extinct, and so the pessimistic population estimate would be zero, however the species has yet to be formally categorised as extinct.
Population Trend
Formerly a conspicuous inhabitant of the upland rainforest streams because of its diurnal (or day-active) habits and historical abundance, the species started disappearing in the southern part of its range in 1988 and had disappeared from the area south of the Daintree River by 1992. In the past the species was considered locally abundant. For example, 1989, 48 calling males were recorded along a 100m stream transect, but surveys of the same site in 1990, found only one adult and some tadpoles.

The decline of this species is well documented and in approximately five years, from 1988 to 1993, it disappeared from an area of approximately 14,000 km² spanning about 2.5 degrees of latitude. The last sightings occurred at Big Tableland in January 1995, in a small tributary of the South Johnstone River in 1996, and the final report was of an egg-carrying female near Hount Hartley, northern Queensland in 1997. Surveys have failed to locate the species, despite extensive searches across suitable sites from the previous range of the species.
Status
The sharp-snouted day frog is classified as Critically Endangered in the 2007 IUCN Red List of Threatened Species because of a drastic population decline, restricted range, and because the total population size is estimated to be very small (less than 250 mature individuals). In fact, this species is presumed to be extinct, although final confirmation of this status is required.

This species also has a national threat status allotted via the Australian Endangered Species Protection Act 1992, where it is registered as “endangered” (schedule 1 listed species).
Threats
The cause of the decline of the sharp-snouted day frog is not well understood, however the sudden decline, including populations within protected areas where other threats are minimal, is typical of a viral infection or the fungus Batrachochytrium dendrobatidis. This fungus causes the disease chytridiomycosis, and is the most likely reason for the species’ decline. In 1993 post-mortem examination of some individuals revealed infection with this fungus, however at this time the devastating effect that the fungus can have on amphibians was not well understood. One study into declines in Australia’s rainforest frogs found no evidence that this species had been affected by drought, floods, habitat destruction or pollution, further supporting the hypothesis that disease was the cause of the rapid population decline. The activity of feral pigs in the area increased from 1989 to 1992, but although the species may cause habitat damage, the direct effect of this on frogs has not been studied.

If this species is still surviving it is likely to be in small, highly fragmented populations, which represent a hurdle to recovery; the effects of small isolated populations on recovery are not well understood, however factors such as low genetic diversity and possible increased susceptibility to disease may slow any population increases.
Conservation Underway
Research and monitoring of the species is ongoing, and a relatively large amount of this species’ habitat is covered by national parks, including Cedar Bay, Daintree, Wooroonooran, Mt Hypipamee, Tully Falls and Lumholtz. However no amount of protected areas can safeguard the species from the suspected cause of decline, chytrid fungus. Even a captive rearing programme for the sharp-snouted torrent frog succumbed to the fungus; the programme between Melbourne Zoo and the Queensland Department of the Environment ran from 1996 to 2006, however despite tadpoles being raised to metamorphosis, and one frog to adulthood, all individuals were infected with chytrid fungus.
Conservation Proposed
A programme to monitor sites throughout the historical range of the sharp-snouted day frog is required so that any remaining wild populations might be found. If an extant wild population is discovered, a priority should be to set up a captive breeding programme, as is recommended by the IUCN for all Critically Endangered species. In the meantime, research into the most effective husbandry for similar species should be carried out and the best technique developed in order to ensure as far as possible that a captive breeding programme would be a success, should any living specimens by found.

Further research is also required into the cause of the decline of the species, including investigating the occurrence of chytrid and other diseases in preserved specimens, and other species of frog from the same region. Finally, research into the management of pathogens is required if the ultimate aim of halting the devastating effects of chytrid fungus is to be achieved.
Links
References
AmphibiaWeb: Information on amphibian biology and conservation [web application]. 2006. Berkeley, California: AmphibiaWeb. Available: amphibiaweb. Accessed: 01 December 2006.

Berger, L., Speare, R. and Hyatt, A. 1999. Chytrid fungi and amphibian declines: overview, implications and future directions. Declines and Disappearances of Australian Frogs. Campbell, A.,editor. 23-33. Environment Australia. Canberra.

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

Dennis, A. and Mahony, M. 1984. Experimental translocation of the endangered sharp-snouted day frog Taudactylus acutirostris and observations on the cause of declines among montane riparian frogs. Unpublished report to Wet Tropics Management Authority. 45.

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

Hero, J.-M., Hines, H.B., Meyer, E., Morrison, C. and Streatfeild, C. 2002. New records of "declining" frogs in Queensland (- April 1999). Frogs in the Community - Proceedings of the Brisbane Conference 13-14 February 1999. Natrass, R. (Ed.). 23-28. Queensland Museum.

Hero, J.-M., Hines, H.B., Meyer, E., Morrison, C., Streatfeild, C and Roberts, L. 1998. New records of "declining" frogs in Queensland, Australia. FrogLog. 29:1-4.

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

IUCN, Conservation International and NatureServe. 2006. Global Amphibian Assessment. Global Amphibian Assessment. Accessed on 01 December 2006.

Liem, D.S. 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, C.J. 1998. The reappearance of Taudactylus (Anura: Myobatrachidae) in north Queensland streams. Pacific Conservation Biology. 4:39-41.

McDonald, K.R., Cunningham, M., Alford, R. and Retallick, R. 2004. Taudactylus acutirostris. In: IUCN 2006. 2006 IUCN Red List of Threatened Species. IUCN Red List of Threatened Species. Downloaded on 01 December 2006.

McDonald, K.R. 1992. Distribution patterns and conservation status of north Queensland rainforest frogs. Conservation Technical Report No. 1. Queensland Department of Environment and Heritage. Brisbane, Australia.

Richards, S.J., McDonald, K.R. and Alford, R.A. 1993. Declines in populations of Australia's endemic tropical rainforest frogs. Pacific Conservation Biology. 1:66-77.

Schloegel, L., J.-M. Hero, L. Berger, R. Speare, K. McDonald and P. Daszak. 2006. The decline of the sharp-snouted day frog (Taudactylus acutirostris): The first documented case of extinction by infection in a free-ranging wildlife species? Ecohealth. 3: 35-40.

Tyler, M.J. 1997. The Action Plan for Australian Frogs. Wildlife Australia. Canberra.

Weldon, C., du Preez, L.H., Hyatt, A.D., Muller, R. and Speare, R. 2004 Origin of the amphibian chytrid fungus. Emerging Infectious Diseases. 10(12): 2100-2105.

Williams, S.E. and Hero, J.-M. 1998. Rainforest frogs of the Australian Wet Tropics: guild classification and the ecological similarity of declining species. Proceedings of the Royal Society of London B. 265:597-602.

Williams, S.E. and Hero, J.-M. 2001. Multiple determinants of Australian Tropical Frog Biodiversity. Biological Conservation. 98:1-10.

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Forum comments
  1. wildam
    Member

    Sharp-snouted Day frog

    http://www.arf.net.au/frogs/frog_images/21)-Sharp-Snouted-Dayfrog.jpg

    Posted 8 years ago #

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