Gastric-brooding frog

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Unique species in the animal kingdom is no more

Evolutionary unique of Amphibia, East Australian Brooding frog is no more.
Assuming the IUCN Redlist database with data from Eungella National Park and all the zoologists of ASG, where the lack of the Stomach Breeding Frogs during 25 years of research came hard. The two species of frogs of the genus Rheobatrachidae can be considered very unique because of the extraordinary development of the larvae to fully metamorphosed young frogs, that what appears to be the development of the highly endangered family bekbroeders (Rhinodermatidae) from Chile.
The bekbroeders take the eggs in a throat pouch which they develop.

The Rheobatrachus species are described as stomach brothers, they swallow the eggs through, to let develop. Tadpoles in the stomach During this process, the metabolism stops completely, so there'll no food included. Only females do this, the number born frogs always appeared, however, lower than the number of fertilized eggs, however, it is not clear why that is, the larvae survived their yolk and probably not from each other. By "hatching" in the stomach offspring was protected from dehydration, moldiness and predation, though, were the frogs for reproduction no longer dependent on surface water, which is a big advantage to virtually all other types of frogs and toads.
Unfortunately, only in the 70s discovered unique animals, after intensive investigations in the 80's not found, a breeding program was initiated by a study group with a number of individuals was also no avail. Since the first kind Rheobatrachus silus (Liem, 1973) around 1973 got its existence, already marked decline in the population were known in 1981, discovered surprising .. the second kind Rheobatrachus vitellinus, (Mahony, 1984/85 Davis) was only discovered in 1984, during the disappearance of Rheobatrachus Silus, the last specimen in captivity in 1983, lost his life. The Rheobatrachus vitellinus (Eungella Gastric-brooding frog) was found only in the Eungella National Park, a few hundred kilometers north of the R.silus. This was after many a field study in the 90 years to 1999, not teruggevonden.Beide species are extinct in 2002 as recorded on the IUCN Redlist.

Reason disappearance

The reason for disappearance and ultimate (verm.) extinction of this species is not clear, there were no direct evidence or reasons that could lead to extinction, one still expects to be able to give. Answer here
Despite the probable extinction is a management / recovery set that should lead to restore the extinct population.

Coverage of the IUCN

Jean-Marc Hero, Keith McDonald, Ross Alford, Michael Cunningham, Richard Retallick 2004. Rheobatrachus vitellinus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. www.iucnredlist.org

Only recently discovered, the southern gastric-brooding frog is now believed to be extinct. The body was grey on the back with variable darker and lighter patches, whilst the underparts were white with large creamy markings. There was a dark streak running from the eye to the forelimbs. The small, flattened head featured large, protruding eyes and the toes were fully webbed.

This super-adapted species which found a way to protect its offspring against droughts, predation and dangerous infections has this unique feature that is never seen in the Animal Kingdom before. Despites the protection for the youngsters, the adults of the juveniles don’t need freshwater surfaces to survive all the time … Sadly researchers couldn’t find any living individuals anymore since 1984,the IUCN and ARC registered the genus with its two species as Globally Extinct (Ex) untill further notice.

The southern gastric brooding frog was first discovered in 1972 in pristine rainforest in the Blackhall and Conodale Ranges in south east Queensland. Here it occupied a small range of less than 1,400km2 and was restricted to elevations between 350 – 800m.

This species inhabited clear, cool, fast flowing streams in the catchments of the Mary, Stanley and Mooloolah Rivers, which flow through pristine rainforests. These streams are generally boulder-strewn, and individuals hid between or beneath boulders in the main stream or backwaters.

This frog was small and oval in shape with females ranging in length from 45-54 mm and males in the range of 33-41 mm. Individuals possessed large eyes that protruded upwards from their small, flattened head. The skin colour on their backs ranged from dull grey to slate, while the belly was white with creamy patches. As an adaptation for their strict freshwater lifestyle, this species had extensively webbed feet.

The southern gastric brooding frog employed one of the most original life-history strategies in the animal kingdom –brooding of the young within the stomach of the mother. Females would swallow their fertilised eggs and allow the young frogs to develop into tadpoles, and subsequently froglets. During the brooding period the female’s digestive process would shut down and her stomach would become so bloated that her lungs would collapse under the pressure, forcing her to rely solely on gas exchange through her skin for respiration. It was observed that during pregnancy females remained completely active even though their buoyancy and centre of gravity were affected to the point that when resting they floated vertically, rather than horizontally, in the stream.

Following its discovery in 1972 the southern gastric brooding frog was thought to be relatively abundant across its range until 1979. A study in 1976 revealed that there were 78 individuals in a population of the species located in the headwaters of Booloumba Creek in the Conondale range. The species declined rapidly and disappeared in a relatively short period of time, and the last individual was seen in the wild in 1979. Since then concerted efforts and surveys have tried to locate the species without any success.

The exact cause of the species’ decline is still not known. Because of the rapid nature of its extinction it is difficult for researchers to pin-point an exact cause. Although there was a small amount of commercial logging operations within the species’ range, the effects of which were never investigated, individuals were present in the logging catchments from 1972 through to 1979. It is now thought that the cause of the species disappearance is probably due to infection within the population of a virulent pathogen, most probably the chytrid fungus Batrachochytrium dendrobatidis which has been implicated in the declines of many amphibian species worldwide.

It is now known that the southern gastric brooding frog was one of the first of a series of amphibian extinctions that occurred from the late 1970s until the early 1990s within Queensland and the Northern territories. This series of extinctions began in southeast Queensland with the declines of this species and the southern day frog, Taudactylus diurnus. It continued into the mid 1980s with the disappearance of the northern gastric brooding frog, and the severe decline in numbers of the northern day frog, Taudactylus eungellensis. Finally several species on the Big Tableland of northern Queensland became extinct in the early 1990s. This wave of population decline and species extinction occurred at a rate of about 100 km per annum and is typical of epidemics spreading within a population without immunity.