Жасыл-алтын қоңыраж бақасы

Species of amphibian
the frog found in Southwest Australia

The green and golden bell frog (Ranoidea aurea), also named the green bell frog, green and golden swamp frog and green frog, is a species of ground dwelling tree frog native to eastern Australia. Despite its classification and climbing abilities, it does not live in trees and spends almost all of its time close to ground level. It can reach up to in length, making it one of Australia's largest frogs. Coloured gold and green, the frogs are voracious eaters of insects, but will also eat larger prey, such as worms and mice. They are mainly diurnal, although this is mostly to warm in the sun. They tend to be less active in winter except in warmer or wetter periods, and breed in the warmer months. Males reach maturity after around 9 months, while for the larger females, this does not occur until they are two years old. The frogs can engage in cannibalism, and males frequently attack and injure one another if they infringe on one another's space. Many populations, particularly in the Sydney region, inhabit areas of infrequent disturbance, such as golf courses, disused industrial land, brick pits, and landfill areas. Though once one of the most common frogs in south east Australia, the green and golden bell frog has endured major population declines, particularly in highland areas, leading to its current classification as globally endangered. Its numbers have continued to fall and are threatened by habitat loss and degradation, pollution, introduced species, and parasites and pathogens, including the chytrid Batrachochytrium dendrobatidis. The specific epithet aurea derived from the Latin aureus for 'golden'. The species is now classified within the Ranoidea aurea complex, a closely related group of frogs in the genus Ranoidea. This complex is scattered throughout Australia: three species occur in south east Australia, one in northern Australia, and two in Southwest Australia. Ranoidea aurea is equally and most closely related to R. castanea and R. raniformis. A microcomplement fixation technique using serum albumins has indicated the species closest to R. aurea is R. ranifomis. Albumin immunological distance data suggest no differentiation between the two, and the green and golden bell frog evolutionally separated from the other two species about 1.1 million years ago. A 1995 study of protein variations showed four of 19 protein systems had variation and only two had differentiation.

The green and golden bell frog is native to south eastern Australia. Before its decline in population, its distribution ranged from Brunswick Heads, in northern New South Wales, to East Gippsland, in Victoria, and west to Bathurst, Tumut and the Australian Capital Territory. The bell frog's current distribution now ranges from Byron Bay, in northern New South Wales, to East Gippsland, in Victoria; populations mostly occur along the coast. There are now approximately only 40 sites in total where it is found, most of which are in the Sydney area. The declines in Victoria have been more modest and mostly in at inland areas where habitats have disappeared. The green and golden bell frog survives in some areas of Sydney, such as the Brickpit at Sydney Olympic Park (the proposed site for the tennis courts for the 2000 Sydney Olympics). When the green and golden bell frog was found there, the tennis courts were built elsewhere, and the population has since been monitored. This frog has become an unofficial mascot for the Homebush Bay area. It has also been introduced to places in Sydney in its natural habitat, without much success.

The green and golden bell frog is a large, stout frog; adults range from in length; typical specimens measure Mature males are generally smaller than mature females, and the colour on their dorsal surfaces differ greatly from females. It may be almost completely green, of shades from dark pea green to bright emerald, green with metallic, brassy, dull copper brown, or gold markings; or almost completely bronze. They can also darken in this way by simply staying in a dark place for a few minutes, and the colour can also change during the frogs' lifetimes. During the breeding season, females develop a blueish hue on their feet, while males' legs turn rusty orange.

As a member of the tree frog family, the green and golden bell frog spends much time basking in the sun on vegetation, rocks, and reeds, usually near water, or hopping around between such places. Unlike most frog species, it is often active during the day. When handled, this species secretes a slimy acrid mucus, which consists of 17 aurein peptides. Thirteen of these show broad spectrum antibiotic and anticancer activity. The secretion makes the frog slippery and hard to grip, and is poisonous to some other species of frogs, so it is a useful defensive tool for green and golden bell frogs. The green and golden bell frog has been detected and prefer a wide range of habitats. It is generally associated with coastal swamps, wetlands, marshes, dams, ditches, small rivers, woodlands, and forests, but populations have also been found at former industrial sites (for instance, the Brickpit). It has even been found in human vessels such as bathtubs. It is most typically found in short lived freshwater ponds that are still, shallow, unshaded, and unpolluted, and it tends to avoid waters that contain predatory fish, whether native or introduced. It prefers waterways with a substrate of sand, rock, or clay, Some have been observed up to 400 m from the nearest body of water. and breeding is significantly slowed for ponds that measure or below. The pH of the pond is not found to affect the likelihood of the eggs to hatch for values between 4 and 10. They have a strong tendency for cannibalism, and frequently these in the same enclosure devour each other. Studies and trials in the wild have shown cannibalism also occurs in the wild. Tadpoles in more advanced phases of development may show a preference for vegetable matter, but also scavenge or become carnivorous on aquatic life. Captive tadpoles have eaten boiled lettuce and pet food in pellet form. Predation on adult frogs has been recorded for the red bellied black snake, tiger snake, The female moves around while depositing, leaving a trail of eggs that sometimes entangles upon itself. Towards the end of the tadpole phase, hind legs appear, followed by front limbs, and the phase ends when the front limbs are developed. This normally occurs between October and April due to the breeding season, but tadpoles been observed in the wild throughout the year, suggesting some tadpoles overwinter; this has been seen to occur for captive tadpoles. The length of the tadpole stage, in the wild and in captivity, is usually between 10 and 12 weeks, but can range from five weeks to a year. The slower growing tadpoles usually progress during winter, as there is a positive correlation between growth rates and temperatures. Variation in growth rate across pH values of 4, 7 and 9 was insignificant. In the first four weeks, there was no significant dependence of the growth rate across the 18–26 °C range, but from this point on, growth was significantly hindered at 18 °C. The process is slowed at low temperatures, but generally takes between three and eight days after the tadpole stage is complete. After metamorphosis is complete, the frog is around the same length. The juveniles initially grow rapidly, reaching 45 mm within two months, 50–60 mm within half a year, before growth slows. Once sexual maturity is reached, the frogs' physical growth is very slow. While it is known to live 10–15 years in captivity, the frog's lifespan in the wild is not well understood. Although it is only classified as vulnerable at national level, the National Frog Action Plan classifies the green and golden bell frog as endangered. Many factors are thought to be responsible for the dramatic decline of this species in Australia, including habitat fragmentation, erosion and sedimentation of soil, insecticides and fertilisers contaminating water systems, Laboratory studies have demonstrated the eggs and tadpoles of the green and golden bell frog are extremely susceptible to predation by this fish, and loss of habitat through the destruction of wetlands. The frogs may have become more susceptible to chytrid rather than the fungus being more common. The cannibalism of the frog has been speculated to cause its decline in some areas, because the smaller tadpoles can be toxic. The green and golden bell frog has been the subject of much research and monitoring, important to improving its conservation. Research focuses on the development of management measures to keep the introduced mosquitofish under control. There have been calls for legislation to be introduced to stop habitat degradation on private land to prevent detrimental effects to the frogs. As public awareness has increased, documentary and news segments on the deteriorating situation have become more frequent and references to the frog in environmental logos and artworks have increased. The effort to increase public consciousness of the green and golden bell frog has also been aided because its colours are the same as the national colours. As green and golden bell frogs are mostly observed in environments disturbed by humans, targeted environmental interference is seen as a possible means of enhancing habitats. The program has since branched off into several other areas. Between 1998 and 2004, tadpoles were released into specially designed ponds and dams on Long Reef Golf Course at Collaroy in northern Sydney, with little success. Although green and golden bell frogs had previously been located in the area, the population had since been lost. Mature male bell frogs are occasionally found there; however, a permanent breeding population has yet to be established. An attempted reintroduction at Marrickville in inner Sydney has failed due to chytridiomycosis.