Gastric-brooding frog
Encyclopedia
The gastric-brooding frogs or Platypus frogs (Rheobatrachus) were a genus
of ground-dwelling frog
s native to Queensland
in eastern Australia
. The genus consisted of only two species, both of which became extinct in the mid-1980s. The genus was unique because it contained the only two known frog species that incubate
d the prejuvenile stages of their offspring in the stomach
of the mother.
The combined ranges of the gastric-brooding frogs comprised less than 2000 km² (800 mi²). Both species were associated with creek systems in rainforest
s at elevation
s of between 350 metres (1,148.3 ft) and 1400 metres (4,593.2 ft). The causes of the gastric-brooding frogs' extinction are not clearly understood, but habitat loss and degradation, pollution, and some diseases may have contributed.
The assignment of the genus to a taxonomic family
is hotly debated. Some biologists class them within Myobatrachidae
under the subfamily Rheobatrachinae, but others place them in their own family, Rheobatrachidae.
, Rheobatrachinae, in a separate family, Rheobatrachidae, placed as the sister-taxon of Limnodynastinae and Rheobatrachinae has been synonym
ized with Limnodynastinae. Frost et al. (2006) found Rheobatrachus, on the basis of molecular evidence, the sister taxon of Mixophyes and placed it within Myobatrachidae.
Both species of gastric-brooding frogs were very different in appearance and behaviour to other Australian frog species
. Their large protruding eyes and short, blunt snout along with complete webbing and slimy bodies differentiated them from all other Australian frogs. The largely aquatic behaviour exhibited by both species was only shared (in Australia) with the Dahl's Aquatic Frog
and their ability to raise their young in the mother's stomach
was unique among all frogs.
" describes their largely aquatic nature.
). Rheobatrachus silus was restricted to the Blackall Range and Conondale Range
s in southeast Queensland
, north of Brisbane
, between elevations of 350 m and 800 m (1100 and 2600 feet) above sea level. The areas of rainforest
, wet sclerophyll
forest and riverine gallery open forest that it inhabited was limited to less than 1,400 km² (540 mi²). They were recorded in streams in the catchments of the Mary
, Stanley
and Mooloolah Rivers. Depending on the source, the last specimen seen in the wild was in 1979 in the Conondale Range, or in 1981 in the Blackall Ranges. The last captive specimen died in 1983. This species is believed to be extinct.
The Southern Gastric-brooding Frog was a dull grey to slate coloured frog that had small patches, both darker and lighter than the background colouration, scattered over dorsal surface (back). The ventral surface was white or cream, occasionally with yellow blotches. The arms and legs had darker brown barring above and were yellow underneath. There was a dark stripe that ran from the eye to the base of the forelimb. The ventral surface (belly) was white with large patches of cream or pale yellow. The toes and fingers were light brown with pale brown flecking. The end of each digit had a small disc and the iris
was dark brown. The skin was finely granular and the tympanum
was hidden. The male Southern Gastric Brooding Frog was 33 millimetres (1.3 in) to 41 millimetres (1.6 in) in length and the female 44 millimetres (1.7 in) to 54 millimetres (2.1 in) in length.
The call of the Southern Gastric-brooding Frog has been described as an "eeeehm...eeeehm" with an upward inflection. It lasts for around 0.5 of a second and was repeated every 6-7 seconds.
Southern Gastric Brooding Frogs have been observed feeding on insects from the land and water. In aquarium situations Lepidoptera
, Diptera
and Neuroptera
were eaten.
Being a largely aquatic species the Southern Gastric-brooding Frog was never recorded more than 4 m (13 ft) from water. Studies by Glen Ingram showed that the movements of this species were very restricted. Of ten juvenile frogs, only two moved more than 3 metres between observations. Ingram also recorded the distance moved along a stream by seven adult frogs between seasons (periods of increased activity, usually during summer). Four females moved between 1.8-46 m (6-151 ft) and three males covered 0.9-53 m (3-174 ft). Only three individuals moved more than 5.5 m (18 ft) (46 m, 46 m and 53 m). It appeared that throughout the breeding season adult frogs would remain in the same pools or cluster of pools, only moving out during periods of flooding or increased flow.
in Eungella National Park
in central eastern Queensland. This species, too, was confined to a small area — less than 500 km² (200 mi²), between 400 and 1000 metres (1000 and 3000 feet) in altitude. Only a year after its discovery, it was never seen again despite extensive efforts to locate it. This species is considered to be extinct.
Male Northern Gastric-brooding Frogs call from the water's edge during summer. The call was loud, consisting of several staccato notes. It is similar to the Southern Gastric-brooding Frogs call although deeper, shorter and repeated less often.
The Northern Gastric-brooding Frog has been observed feeding on small crayfish
, caddisfly larvae and terrestrial and aquatic beetles as well as the Eungella Torrent Frog
(Taudactylus eungellensis).
Eggs found in females measured up to 5.1 mm in diameter and had large yolk supplies. These large supplies are common among species that live entirely off yolk during their period of development. Most female frogs possessed around 40 ripe eggs. This number is almost double that of the number of juveniles ever to be observed occurring in the stomach (21-26). This means one of two things, that the female fails to swallow all the eggs or the first few eggs to be swallowed are digested.
At the time the female ingested the fertilized eggs her stomach was no different from that found in any other frog species. In the jelly that surrounded each egg was a substance called prostaglandin
E2 (PGE2). This substance had the ability to turn off the production of hydrochloric acid
in the stomach. This source of PGE2 was enough to cease the production of acid during the embryonic stages of the developing eggs. Once the eggs had hatched the tadpoles too created PGE2. The mucus excreted from the tadpoles gills contained the PGE2 necessary to maintain the stomach in a non-functional state. These mucus excretions do not occur in tadpoles of most other species. Tadpoles that don't live entirely off a yolk supply still produce mucus cord, but the mucus along with small food particles travels down the oesophagus into the gut. With Rheobatrachus (and several other species) there is no opening to the gut and the mucus cords are excreted. During the period that the offspring were present in the stomach the frog would not eat.
Information on tadpole development was observed by a group that was regurgitated by the mother and successfully raised in shallow water. During the early stages of development tadpoles lacked pigmentation, but as they aged they progressively develop adult colouration. Tadpole development took at least six weeks, during this time the size of the mother’s stomach continued to increase until it largely filled the body cavity. The lungs deflated and breathing relied more upon gas exchange through the skin. Despite the mothers increasing size she still remained active.
The birth process was widely spaced and may have occurred over a period of as long as a week. However, if disturbed the female may regurgitate all the young frogs in a single act of propulsive vomiting. The offspring were completely developed when expelled and there was little variation in colour and length of a single clutch.
Populations of Southern Gastric-brooding Frogs were present in logged catchments between 1972 and 1979. The effects of such logging activities upon Southern Gastric-brooding Frogs was not investigated but the species did continue to inhabit streams in the logged catchments. The habitat that the Southern Gastric-brooding Frog once inhabited is now threatened by feral pigs, the invasion of weeds, altered flow and water quality problems caused by upstream disturbances. Despite intensive searching, the species has not been located since 1979 or 1981 (depending on the source).
The Eungella National Park, where the Northern Gastric-brooding Frog was once found, was under threat from bushfires and weed invasion. Continual fires may have destroyed or fragmented sections of the forest. The outskirts of the park are still subject to weed invasion and chytrid fungus has been located within several rainforest creeks within the park. It was thought that the declines of the Northern Gastric-brooding Frog during 1984 and 1985 were possibly normal population fluctuations. Despite continued efforts to locate the Northern Gastric-brooding Frog it has not been found. The last reported wild specimen was seen in the 1980s. In August 2010 a search organised by the Amphibian Specialist Group of the International Union for Conservation of Nature set out to look for various species of frogs thought to be extinct in the wild, including the gastric-brooding frog.
and under Australia
's Environment Protection and Biodiversity Conservation Act 1999
; however, they are still listed as Endangered under Queensland's Nature Conservation Act 1992
.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of ground-dwelling frog
Frog
Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...
s native to Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
in eastern Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. The genus consisted of only two species, both of which became extinct in the mid-1980s. The genus was unique because it contained the only two known frog species that incubate
Avian incubation
Incubation refers to the process by which certain oviparous animals hatch their eggs, and to the development of the embryo within the egg. The most vital factor of incubation is the constant temperature required for its development over a specific period. Especially in domestic fowl, the act of...
d the prejuvenile stages of their offspring in the stomach
Stomach
The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...
of the mother.
The combined ranges of the gastric-brooding frogs comprised less than 2000 km² (800 mi²). Both species were associated with creek systems in rainforest
Rainforest
Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...
s at elevation
Elevation
The elevation of a geographic location is its height above a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface ....
s of between 350 metres (1,148.3 ft) and 1400 metres (4,593.2 ft). The causes of the gastric-brooding frogs' extinction are not clearly understood, but habitat loss and degradation, pollution, and some diseases may have contributed.
The assignment of the genus to a taxonomic family
Family
In human context, a family is a group of people affiliated by consanguinity, affinity, or co-residence. In most societies it is the principal institution for the socialization of children...
is hotly debated. Some biologists class them within Myobatrachidae
Myobatrachidae
Myobatrachidae is a family of frogs found in Australia and New Guinea. Members of this family vary greatly in size, from species less than long, to the second largest frog in Australia, the Giant Barred Frog , at in length...
under the subfamily Rheobatrachinae, but others place them in their own family, Rheobatrachidae.
Taxonomy
Rheobatrachus was first described in 1973 by Liem and since has not undergone any scientific classification changes; however the placement of this genus within a family has been controversial. It has been placed in a distinct subfamily of MyobatrachidaeMyobatrachidae
Myobatrachidae is a family of frogs found in Australia and New Guinea. Members of this family vary greatly in size, from species less than long, to the second largest frog in Australia, the Giant Barred Frog , at in length...
, Rheobatrachinae, in a separate family, Rheobatrachidae, placed as the sister-taxon of Limnodynastinae and Rheobatrachinae has been synonym
Synonym
Synonyms are different words with almost identical or similar meanings. Words that are synonyms are said to be synonymous, and the state of being a synonym is called synonymy. The word comes from Ancient Greek syn and onoma . The words car and automobile are synonyms...
ized with Limnodynastinae. Frost et al. (2006) found Rheobatrachus, on the basis of molecular evidence, the sister taxon of Mixophyes and placed it within Myobatrachidae.
Both species of gastric-brooding frogs were very different in appearance and behaviour to other Australian frog species
Amphibians of Australia
Amphibians of Australia are limited to members of the order Anura, commonly known as frogs. All Australian frogs are in the suborder Neobatrachia, also known as the modern frogs, which make up the largest proportion of extant frog species. About 230 of the 5,280 species of frog are native to...
. Their large protruding eyes and short, blunt snout along with complete webbing and slimy bodies differentiated them from all other Australian frogs. The largely aquatic behaviour exhibited by both species was only shared (in Australia) with the Dahl's Aquatic Frog
Dahl's Aquatic Frog
The Dahl's Aquatic Frog is a species of frog in the Hylidae family. It is endemic to Australia.Its natural habitats are dry savanna, subtropical or tropical dry lowland grassland, freshwater lakes, intermittent...
and their ability to raise their young in the mother's stomach
Stomach
The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...
was unique among all frogs.
Common names
The common names, "Gastric-brooding frog" and "Platypus frog", are used to describe the two species. "Gastric-brooding" described the unique way the female raised the young and "platypusPlatypus
The platypus is a semi-aquatic mammal endemic to eastern Australia, including Tasmania. Together with the four species of echidna, it is one of the five extant species of monotremes, the only mammals that lay eggs instead of giving birth to live young...
" describes their largely aquatic nature.
Distribution
The Southern Gastric-brooding Frog (Rheobatrachus silus) was discovered in 1972 and described in 1973, however, there is one publication suggesting that the species was discovered in 1914 (from the Blackall RangeBlackall Range
The Blackall Range is a mountain range in South East Queensland, Australia. The first European explorer in the area was Ludwig Leichhardt. It was named after Samuel Blackall, the second Governor of Queensland....
). Rheobatrachus silus was restricted to the Blackall Range and Conondale Range
Conondale Range
The Conondale Range is a mountain range in Queensland, located between Maleny, Kenilworth, Kilcoy and Jimna. The range is the most westerly part of the Sunshine Coast hinterland and part of the Great Dividing Range. The highest point on the range is Mount Langley reaching 868 m above sea level...
s in southeast Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
, north of Brisbane
Brisbane
Brisbane is the capital and most populous city in the Australian state of Queensland and the third most populous city in Australia. Brisbane's metropolitan area has a population of over 2 million, and the South East Queensland urban conurbation, centred around Brisbane, encompasses a population of...
, between elevations of 350 m and 800 m (1100 and 2600 feet) above sea level. The areas of rainforest
Rainforest
Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...
, wet sclerophyll
Sclerophyll
Sclerophyll is the term for a type of vegetation that has hard leaves and short internodes . The word comes from the Greek sclero and phyllon ....
forest and riverine gallery open forest that it inhabited was limited to less than 1,400 km² (540 mi²). They were recorded in streams in the catchments of the Mary
Mary River (Queensland)
The Mary River is a river system in South East Queensland, Australia. The river rises at Booroobin in the Sunshine Coast hinterland, west of Landsborough...
, Stanley
Stanley River (Queensland)
The Stanley River in Queensland is the main tributary of the Brisbane River. The Stanley River valley extends roughly 35 km westwards from the area south of Maleny to Kilcoy before veering southwards....
and Mooloolah Rivers. Depending on the source, the last specimen seen in the wild was in 1979 in the Conondale Range, or in 1981 in the Blackall Ranges. The last captive specimen died in 1983. This species is believed to be extinct.
Physical description
The Southern Gastric-brooding Frog was a medium sized species of dull colouration, with large protruding eyes positioned close together and a short, blunt snout. Its skin was moist and coated with mucus. The fingers were long, slender, pointed and unwebbed and the toes were fully webbed. The arms and legs were large in comparison to the body. In both species the females were larger than the males.The Southern Gastric-brooding Frog was a dull grey to slate coloured frog that had small patches, both darker and lighter than the background colouration, scattered over dorsal surface (back). The ventral surface was white or cream, occasionally with yellow blotches. The arms and legs had darker brown barring above and were yellow underneath. There was a dark stripe that ran from the eye to the base of the forelimb. The ventral surface (belly) was white with large patches of cream or pale yellow. The toes and fingers were light brown with pale brown flecking. The end of each digit had a small disc and the iris
Iris (anatomy)
The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...
was dark brown. The skin was finely granular and the tympanum
Tympanum (zoology)
The tympanum is an external hearing structure in animals such as frogs, toads, insects, and mammals, to name a few.-Anurans:In frogs and toads, it is located just behind the eye. It does not actually process sound waves; it simply transmits them to the amphibian's inner ear, which is protected...
was hidden. The male Southern Gastric Brooding Frog was 33 millimetres (1.3 in) to 41 millimetres (1.6 in) in length and the female 44 millimetres (1.7 in) to 54 millimetres (2.1 in) in length.
Ecology and behaviour
The Southern Gastric-brooding Frog lived in areas of rainforest, wet sclerophyll forest and riverine gallery open forest. They were a predominately aquatic species closely associated with watercourses and adjacent rock pools and soaks. Streams that the Southern Gastric Brood Frog were found in were mostly permanent and only ceased to flow during years of very low rainfall. Sites where Southern Gastric-brooding Frogs were found usually consisted of closed forests with emergent eucalypts, however there was sites where open forest and grassy ground cover were the predominate vegetation. There is no record for this species occurring in cleared riparian habitat. Searches during spring and summer showed that the favored diurnal habitat was at the edge of rock pools, either amongst leaf litter, under or between stones or in rock crevices. They were also found under rocks in shallow water. Winter surveys of sites where Southern Gastric Brooding Frogs were common only recovered two specimens, and it is assumed that they hibernated during the colder months. Adult males preferred deeper pools than the juveniles and females which tended to inhabit shallower, newly created (after rain) pools that contained stones and/or leaf litter. Individuals only left themselves fully exposed while sitting on rocks during light rain.The call of the Southern Gastric-brooding Frog has been described as an "eeeehm...eeeehm" with an upward inflection. It lasts for around 0.5 of a second and was repeated every 6-7 seconds.
Southern Gastric Brooding Frogs have been observed feeding on insects from the land and water. In aquarium situations Lepidoptera
Lepidoptera
Lepidoptera is a large order of insects that includes moths and butterflies . It is one of the most widespread and widely recognizable insect orders in the world, encompassing moths and the three superfamilies of butterflies, skipper butterflies, and moth-butterflies...
, Diptera
Diptera
Diptera , or true flies, is the order of insects possessing only a single pair of wings on the mesothorax; the metathorax bears a pair of drumstick like structures called the halteres, the remnants of the hind wings. It is a large order, containing an estimated 240,000 species, although under half...
and Neuroptera
Neuroptera
The insect order Neuroptera, or net-winged insects, includes the lacewings, mantidflies, antlions, and their relatives. The order contains some 6,010 species...
were eaten.
Being a largely aquatic species the Southern Gastric-brooding Frog was never recorded more than 4 m (13 ft) from water. Studies by Glen Ingram showed that the movements of this species were very restricted. Of ten juvenile frogs, only two moved more than 3 metres between observations. Ingram also recorded the distance moved along a stream by seven adult frogs between seasons (periods of increased activity, usually during summer). Four females moved between 1.8-46 m (6-151 ft) and three males covered 0.9-53 m (3-174 ft). Only three individuals moved more than 5.5 m (18 ft) (46 m, 46 m and 53 m). It appeared that throughout the breeding season adult frogs would remain in the same pools or cluster of pools, only moving out during periods of flooding or increased flow.
Distribution
The Northern Gastric-brooding Frog (Rheobatrachus vitellinus) was discovered and described in 1984. It was restricted to the rainforest areas of the Clarke RangeClarke Range
The Clarke Range is a rainforest-covered mountain range in Central Queensland, Australia. It forms part of the Great Dividing Range in central Queensland, lying about 30 km from the coast and 65 km west of the coastal city of Mackay...
in Eungella National Park
Eungella National Park
Eungella is a national park in Queensland, Australia, 80 km west of Mackay, and 858 km northwest of Brisbane. The original inhabitants are the Goreng goreng people. The park is covered by dense rainforest and is known for its platypuses.The national park was established in 1941 and is...
in central eastern Queensland. This species, too, was confined to a small area — less than 500 km² (200 mi²), between 400 and 1000 metres (1000 and 3000 feet) in altitude. Only a year after its discovery, it was never seen again despite extensive efforts to locate it. This species is considered to be extinct.
Physical description
The Northern Gastric-brooding Frog was a much larger species than the Southern Gastric-brooding Frog. Males reached 50–53 mm (2.0–2.1 in) in length, and females 66–79 mm (2.6–3.1 in) in length. This species was also much darker in colour, usually pale brown, and like the Southern Gastric-brooding Frogs its skin was bumpy and had a slimy mucus coating. There were vivid yellow blotches on the abdomen and the underside of the arms and legs. The rest of the belly was white or grey in colour. The tympanum was hidden and the iris was dark brown. The body shape of the Northern Gastric Brooding Frog was very similar to the southern species.Ecology and behaviour
The Northern Gastric-brooding Frog was only recorded in pristine rainforests where the only form of human disturbance was poorly defined walking tracks. As with the Southern Gastric-brooding Frog, the Northern Gastric-brooding Frog was also a largely aquatic species. They were found in and around the shallow sections of fast flowing creeks and streams where individuals were located in shallow, rocky, broken-water areas, in cascades, riffles and trickles. The water in these streams was cool and clear, and the frogs hid away beneath or between boulders in the current or in backwaters.Male Northern Gastric-brooding Frogs call from the water's edge during summer. The call was loud, consisting of several staccato notes. It is similar to the Southern Gastric-brooding Frogs call although deeper, shorter and repeated less often.
The Northern Gastric-brooding Frog has been observed feeding on small crayfish
Crayfish
Crayfish, crawfish, or crawdads – members of the superfamilies Astacoidea and Parastacoidea – are freshwater crustaceans resembling small lobsters, to which they are related...
, caddisfly larvae and terrestrial and aquatic beetles as well as the Eungella Torrent Frog
Eungella Torrent Frog
The Eungella Torrent Frog is a species of stream dwelling frog endemic to Australia. It is restricted to ranges west of Mackay in mid-eastern Queensland.-Physical description:...
(Taudactylus eungellensis).
Reproduction
What makes these frogs unique among all frog species is their form of parental care. Following external fertilization by the male, the female would take the eggs into her mouth and swallow them. It is not clear whether the eggs were laid on the land or in the water, as it was never observed prior to their extinction.Eggs found in females measured up to 5.1 mm in diameter and had large yolk supplies. These large supplies are common among species that live entirely off yolk during their period of development. Most female frogs possessed around 40 ripe eggs. This number is almost double that of the number of juveniles ever to be observed occurring in the stomach (21-26). This means one of two things, that the female fails to swallow all the eggs or the first few eggs to be swallowed are digested.
At the time the female ingested the fertilized eggs her stomach was no different from that found in any other frog species. In the jelly that surrounded each egg was a substance called prostaglandin
Prostaglandin
A prostaglandin is any member of a group of lipid compounds that are derived enzymatically from fatty acids and have important functions in the animal body. Every prostaglandin contains 20 carbon atoms, including a 5-carbon ring....
E2 (PGE2). This substance had the ability to turn off the production of hydrochloric acid
Hydrochloric acid
Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....
in the stomach. This source of PGE2 was enough to cease the production of acid during the embryonic stages of the developing eggs. Once the eggs had hatched the tadpoles too created PGE2. The mucus excreted from the tadpoles gills contained the PGE2 necessary to maintain the stomach in a non-functional state. These mucus excretions do not occur in tadpoles of most other species. Tadpoles that don't live entirely off a yolk supply still produce mucus cord, but the mucus along with small food particles travels down the oesophagus into the gut. With Rheobatrachus (and several other species) there is no opening to the gut and the mucus cords are excreted. During the period that the offspring were present in the stomach the frog would not eat.
Information on tadpole development was observed by a group that was regurgitated by the mother and successfully raised in shallow water. During the early stages of development tadpoles lacked pigmentation, but as they aged they progressively develop adult colouration. Tadpole development took at least six weeks, during this time the size of the mother’s stomach continued to increase until it largely filled the body cavity. The lungs deflated and breathing relied more upon gas exchange through the skin. Despite the mothers increasing size she still remained active.
The birth process was widely spaced and may have occurred over a period of as long as a week. However, if disturbed the female may regurgitate all the young frogs in a single act of propulsive vomiting. The offspring were completely developed when expelled and there was little variation in colour and length of a single clutch.
Cause of extinction
The cause for the gastric-brooding frogs' extinction is unknown but habitat loss/degradation, pollution, pathogens, parasites and over collecting may have contributed. A direct threat to the habitats through human activities was not clearly apparent and chytrid fungus is suspected to have caused declines in this species.Populations of Southern Gastric-brooding Frogs were present in logged catchments between 1972 and 1979. The effects of such logging activities upon Southern Gastric-brooding Frogs was not investigated but the species did continue to inhabit streams in the logged catchments. The habitat that the Southern Gastric-brooding Frog once inhabited is now threatened by feral pigs, the invasion of weeds, altered flow and water quality problems caused by upstream disturbances. Despite intensive searching, the species has not been located since 1979 or 1981 (depending on the source).
The Eungella National Park, where the Northern Gastric-brooding Frog was once found, was under threat from bushfires and weed invasion. Continual fires may have destroyed or fragmented sections of the forest. The outskirts of the park are still subject to weed invasion and chytrid fungus has been located within several rainforest creeks within the park. It was thought that the declines of the Northern Gastric-brooding Frog during 1984 and 1985 were possibly normal population fluctuations. Despite continued efforts to locate the Northern Gastric-brooding Frog it has not been found. The last reported wild specimen was seen in the 1980s. In August 2010 a search organised by the Amphibian Specialist Group of the International Union for Conservation of Nature set out to look for various species of frogs thought to be extinct in the wild, including the gastric-brooding frog.
Conservation status
Both species are listed as Extinct under both the IUCN Red ListIUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
and under Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
's Environment Protection and Biodiversity Conservation Act 1999
Environment Protection and Biodiversity Conservation Act 1999
The Environment Protection and Biodiversity Conservation Act 1999 is an Act of the Parliament of Australia that provides a framework for protection of the Australian environment, including its biodiversity and its natural and culturally significant places...
; however, they are still listed as Endangered under Queensland's Nature Conservation Act 1992
Nature Conservation Act 1992
The Nature Conservation Act 1992 is an act of the Parliament of Queensland that provides for the legislative protection of Queensland's threatened biota. As originally published, it provided for biota to be declared presumed extinct, endangered, vulnerable, rare or common...
.
External links
- Animal Diversity Web - Rheobatrachus silus (Accessed - 2006/08/19)
- Frogs Australia Network - Southern Gastric Brooding Frog (Accessed - 2006/08/19)
- Frogs Australia Network - Northern Gastric Brooding Frog (Accessed - 2006/08/19)
- American Museum of Natural History - Rheobatrachus (Accessed - 2006/08/19)
- IUCN RedList - Rheobatrachus silus (Accessed - 2006/08/19)
- IUCN RedList - Rheobatrachus vitellinus( Accessed - 2006/08/19)