Central Asiatic Frog

Vomerine teeth present. Posterior part of the tongue free and forked. Toes webbed. Omosternum and sternum ossified. Pupil of the eye horizontal. Snout sharp. Male vocal sacs reduced. When the shins (knee to ankle) are positioned perpendicularly to the body axis, the heels overlap; when the hind leg is stretched along the body, the tibio-tarsal articulation reaches the eye. Inner metatarsal tubercle large, 2.2-3.9 times shorter than the first toe. Flank and thigh skin smooth. Dorsal coloration greyish to brown, with dark spots. Temporal spot large. Light middorsal line with distinct edges running from eyes to cloaca present regularly. Ventral surface white or whitish-pink with large irregular, partially fused red spots which are well-developed on the posterior part of belly and on the hind legs, almost absent on the throat and chest. Male differs from female by having dark nuptial pads on the first finger.The species needs special measures of protection in Kazakhstan, China and Kirgizia in the near future.

The species lives in the former USSR (southern Kazakhstan and Kirgizia) and China (northwest of the Xinjiang - Uigur Autonomous Region). From the west, the range margin runs in Kirgizia from Kochkor District (Kyzart Village: ca. 42ºN, 75ºE) to Bishkek City to Tokmak Town (42º50'N, 75º18'E). The westernmost record, in Toktogul Hollow (Osh Province in Kirgizia) needs further examination. From Kirgizia, the margin runs in Kazakhstan eastwards and north-eastwards approximately along the line: Dzhambul Province (Chernaya Rechka Village) - Alma-Ata City (43º16'N, 76º56'E) - Charyn River in Uigur District - Panfilov (=Zharkent) District, then to China, where the frog is known from parts of the Ili and Kungess river valleys. The frog was also recorded from the whole of the valley of the Ili River from the mountains to its mouth on the southwestern shore of Balkhash Lake. At present, the species is no longer recorded in a large part of the Ili River valley, Lepsa River, and the shores of Lake Balkhash. It was also known around its shore northwards to Tas-Aral Island near the northwestern shore of the lake in Dzhezkazgan Province of Kazakhstan, as well as in the basin of Lepsa River from the northern slopes of the Junggarian Alatau Ridge to the river mouth on the southeastern shore of Balkhash Lake. The frog may be found also in the basins of the Aksu and Karatal rivers (Kazakhstan) which flow into this lake on its southern shore. The easternmost known locality is Bakhty Settlement in the southern foothills of Tarbagatai Ridge, Semipalatinsk Province (ca. 46º40'N, 82º40'E). Further surveys are necessary, because the range margins of this frog are insufficiently known. The problem of a possible zone of sympatry of this species with the Moor Frog (Rana arvalis) in Eastern Kazakhstan deserves special study. Rana asiatica lives mainly in wooded areas in river valleys within mountains, steppe and deserts. In mountain areas, it lives in swampy areas with seepage water in hollows, canyons, valleys and meadows. In lowlands and foothills, it occurs mainly in meadows and bushlands near ponds, streams, ditches and other sources of water. Such water bodies are frequently temporary and fill with water only after the spring floods. After the water has disappeared, the frogs migrate to other water bodies. In arid areas, the main type of habitat in this species, dense and high riparian vegetation with numerous small ponds and swamps, is quite fragmented, which is reflected high extent of fragmentation of the species range. For spawning, the frog chooses large puddles, swampy pools, flooded ponds, weakly flowing brooks etc. with a soft, muddy bottom, clean water and dense herbaceous vegetation.

At present, R. asiatica is not very common; its population density reaches usually several dozens of individuals per hectare in Kazakhstan, and more at some sites in Kirgizia. However, in the past its density reached few hundred individuals per hectare. Hibernation occurs from September - November to February - March. Hibernation occurs in stagnant or slow-moving waters, usually in groups of several dozen individuals. The frog rarely hibernates on land. Breeding occurs from mid-March - April and until June in highlands. Breeding choruses are absent. Amplexus is pectoral (axial). The spawn is deposited in a single clutch of 600-1700 eggs, but in some cases several portions can be deposited. Metamorphosis in the highlands occurs in August-September, later than in the foothills (late May - June). The maximum age of adult frogs was estimated as 5 years. Tadpoles eat detritus, algae (mainly Bacillariophyta and Cyanophyta), pieces of higher plants and, in smaller amounts, small aquatic invertebrates. Adult frogs consume almost exclusively terrestrial arthropods.

The existence of isolated populations of the Central Asiatic Frog in arid zones makes them very sensitive to anthropogenic alteration of the environment. For example, during the last 60-70 years the frog has became very rare or extinct in Central Kazakhstan, where it was common. This was caused by flooding of riparian groves (tugai) after the construction of Kapchagaiskoe Reservoir. The species may have also been extirpated from areas adjacent to Balkhash Lake. The displacement of R. asiatica by the introduced and dispersing Marsh Frog (Rana ridibunda) in the areas of Issyk-Kul Lake (Kirgizia) and the Ili River valley (Xinjiang) is likely.

Rana asiatica does not avoid anthropogenic landscapes and occurs in gardens, parks, near wells and irrigation ditches. However, populations are very vulnerable to anthropogenic alteration of the landscape, because the arid regions of Central Asia seem to be the zone of the ecological extreme for brown frogs. During the last years, collecting of the Central Asiatic Frog from the Ili River valley (Uigur District, Kazakhstan) for the purposes of Chinese and Uigur traditional medicine has increased. Such collecting may be dangerous for small, isolated populations of this species.

The central Asiatic frog (Rana asiatica), or Asian frog, is a species of true frog, found in China, Kazakhstan, and Kyrgyzstan. Its natural habitats are temperate forests, temperate shrubland, temperate grassland, rivers, intermittent rivers, swamps, freshwater lakes, intermittent freshwater lakes, freshwater marshes, intermittent freshwater marshes, freshwater springs, inland deltas, arable land, pastureland, rural gardens, urban areas, water storage areas, ponds, aquaculture ponds, and irrigated land. It is not considered threatened by the IUCN.