Semirechensky Frogtooth (Ranodon Sibiricus)

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Semirechensky Frogtooth (Ranodon Sibiricus)
Semirechensky Frogtooth (Ranodon Sibiricus)

Video: Semirechensky Frogtooth (Ranodon Sibiricus)

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Video: Семиреченский лягушкозуб (Ranodon sibiricus) 2016 (3'47) 2023, February
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Semirechensky frogtooth, or Dzungarian newt(Ranodon sibiricus) is the largest newt in our country, reaching a length of up to 20 cm. The head is wide, flat with a rounded muzzle. Hind legs have 5 toes. The color is dark olive, in adults it is often spotted. The tail is laterally compressed and has a well-developed fin fold on the dorsal side. Narrow endemic, inhabits only one point of the world in a very small area - Zhetysu (Dzhungar) Alatau in southeastern Kazakhstan (Central Asia) and northwestern Xinjiang (China). Lives in small streams with a rocky bottom, fast current and waterfalls. At an altitude of 1800-2500 m above sea level, at the upper border of forest vegetation. During the day, it keeps under stones or in depressions under an overhanging shore in the water. The main food of the frogtooth consists of caddis flies and amphipods.

Etymology

The Semirechensky frogtooth got its name for the similarity in the arrangement of the teeth with the teeth of frogs.

Semirechensky frogtooth (Ranodon sibiricus), photo photograph tailed amphibians
Semirechensky frogtooth (Ranodon sibiricus), photo photograph tailed amphibians

Semirechensky frogtooth (Ranodon sibiricus). © Arnaud JAMIN

Area

Dzhungarskiy Alatau Ridge in Kazakhstan and northwestern Xinjiang (China).

Appearance

The body is stocky. The head is broad, flat with a rounded muzzle, about 3.5 times shorter than the body. Parotids are clearly expressed. The eyes are large. The skin is moist, slippery, there is no mucus on the skin surface. The teeth are small, conical, bent back or grow at an angle to the plane of the mouth. A longitudinal groove runs along the spine from the occiput to the base of the tail. The body is intercepted from the sides by 11-13 grooves. The frogtooth has four toes on its front legs, and five toes on the hind legs. The body musculature is very strong. The male has a wider and more muscular head, and the tail is longer than that of the female. The cloaca is in the form of a longitudinal slit. The tail is flattened laterally, slightly longer or more or less equal in length to the body, slightly pointed at the end.

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Coloration

Brownish yellow to dark olive and greenish gray; there are also individuals with a pattern of dark spots on a dark olive background 1. The belly is white or off-white. The color of the frogtooth is determined by the environment. Individuals that have been in the water for a long time darken. Completely black specimens are rarely found.

Semirechensky frogtooth (Ranodon sibiricus), picture picture tailed amphibians
Semirechensky frogtooth (Ranodon sibiricus), picture picture tailed amphibians

The size

They grow up to 20 cm (body length without tail is 8.5-9.5 cm).

Habitat

The distribution of the Semirechye frogtooth is associated with the alpine, subalpine, forest and forest-steppe belts, in which a significant area is currently occupied by meadow pastures (zhailau). At an altitude of 1800-2500 m above sea level, at the upper border of forest vegetation. Avoids large rivers. The water temperature in the streams where frogtooths live is from +6 to + 19 ° С. The most suitable for the species are small, shallow streams with sandy, pebble or muddy bottoms. These streams contain numerous large stones and have slow flowing backwaters. The banks of such streams are usually covered with a thick and moist layer of moss or grass with numerous shelters below it, which are often located below the water level. As shelters, newts use cavities in the turf, under stones, logs and tree roots, rodent burrows, etc.

Semirechye frogtooths are resistant to low temperatures and do not lose mobility at about 0 ° C. At + 24 … + 26 ° С they show anxiety, and at + 28 … + 32 ° С they die.

Enemies

The eggs are sometimes eaten by planaria and caddis larvae. The larvae are eaten by birds (gray heron).

Larva of the Semirechye salamander (Ranodon sibiricus), black and white drawing picture amphibians
Larva of the Semirechye salamander (Ranodon sibiricus), black and white drawing picture amphibians

Larva of the Semirechye salamander (Ranodon sibiricus)

Nutrition / food

Adult frogtooths hunt both in water and on land. While hunting in the water, they methodically inspect all areas with a slow current, swimming near the very bottom and inspecting all stones and cracks. Swallow food whole. They eat larvae of caddis flies (70-75%), amphipods (18%), less often insects, arachnids, diptera larvae and worms. On land, they usually watch for prey, sitting in shelters.

Immediately after hatching, the larvae live off yolk reserves. The transition to feeding on invertebrates is very long - from 4 to 14 days. The main food of the larvae is invertebrates. During the period of metamorphosis, the intensity of feeding decreases sharply.

In captivity, they feed on earthworms, crickets, gammarus, pieces of beef heart.

Behavior

Semirechye frogtooths prefer to live in water. Having met an insurmountable waterfall on the way, they can bypass the obstacle by land. During the day they stay on land under stones or small caves hanging over the coast. Do not tolerate sunlight. In the evening, frogtooths of all ages are most active, swimming at the bottom, often crawling under stones in search of food. Often, adult animals, having examined the section of the stream from the waterfall to the waterfall, crawl out onto the shore and move overland to the neighboring section. When disturbed, salamanders go under stones at the bottom, or in cavities in the banks.

In early autumn, the larvae migrate to wintering sites. They hibernate in late September - early October, when the temperature drops sharply and ice edges form on the streams. They hibernate in non-freezing springs under stones or under a cover of moss at the bottom. The Semirechye frogtooths leave their winter shelter in April, although the time of emergence depends on the time of ice and snow melting.

Life span

In nature, they live for about 12 years, in captivity, some individuals live up to 27 years.

Puberty

Maturation begins at 5-6 years of age with a body length of 78 mm.

Breeding season

Falls in mid-April - early August.

Clutch of the Semirechensky frogtooth (Ranodon sibiricus), drawing picture of an amphibian
Clutch of the Semirechensky frogtooth (Ranodon sibiricus), drawing picture of an amphibian

Clutch of Semirechensky frogtooth (Ranodon sibiricus)

Reproduction

Reproduction begins approximately 10-15 days after the end of wintering, i.e. immediately after the ice and snow melt. Frogtooths often breed in the headwaters of streams or small streams, every year in the same places. Fertilization is external. The male sticks spermatophores to stones, less often to the branches of bushes, lowered into the water. Spermatophores look like a small lump, 5-6 mm in diameter, sometimes elongated. Then she attracts the female with games, as a result of which the female attaches two mucous sacs with eggs to the base of the spermatophore. Each bag is 30-35 mm long (8-10 mm in diameter) and contains 18-50 eggs. Fertilized eggs gradually swell, becoming larger and larger, and by the time the larvae are born, they increase in size up to 18-20 millimeters, and the caviar sacs - up to 20-30 centimeters. Each bag contains 25-50 eggs with a diameter of about 10 mm.The eggs are poorly pigmented and quickly die in the sun. In most cases, bags of the same masonry have different sizes. The distribution of clutches in streams is uneven. After the completion of spawning, animals move to mountain rivers, although about a third of them can remain in spawning grounds for some time.

Incubation

At a water temperature of 8-12 ° C, the incubation of eggs lasts 22-25 days.

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Development

After hatching from the eggs, the larvae of the Semirechensky frogtooth remain in the caviar bags for about 4 days, and then go out into the streams through the top of the caviar bag. In nature, hatching begins in June and lasts until September. After one or two days, the larvae move to well-warmed, shallow areas (no more than 10-15 cm deep). They are active during the day, hiding among the stones at the bottom of the reservoir.

If eggs are deposited in the river, then the larvae migrate to the banks and stay under stones in places with a slow current. The length of the larvae at hatching is 17-20 mm. They already have forelimbs with black claws on the 2nd and 3rd fingers, hind limbs in the form of kidneys, a tail surrounded by a wide fin fold, 3 pairs of feathery gills. There are membranes between the toes. With the help of claws, the larvae cling to stones. External nostrils and teeth are missing. The hind limbs (also with claws) appear in larvae that have grown to 30-45 mm. At this age, teeth appear and nostrils are formed. The tail is laterally compressed, surrounded by a wide fin fold. When the frogtooth larva reaches a length of more than 50 mm, its gills will disappear, and the throat fold will grow together with the throat, the membrane on the lower surface of the tail will shorten and become narrow.After metamorphosis, the claws and membranes between the fingers disappear in the larvae. Growth continues during the period of metamorphosis. The larvae usually hibernate, metamorphosing by the end of the next summer. The larval period lasts 3 years. In terrariums at a temperature of + 20 … + 25 ° C, larva development lasts only 5 months.

Hatching the larvae of the Semirechye frogtooth (Ranodon sibiricus)
Hatching the larvae of the Semirechye frogtooth (Ranodon sibiricus)

Hatching of larvae of the Semirechye frogtooth (Ranodon sibiricus)

Benefit / harm to humans

In Chinese medicine, Semirechye frogtooths are used as a remedy to accelerate bone fusion. There was a belief among the local population that the Semirechsky frogtooth could cure a variety of diseases, for example, remove warts on the body, heal bleeding wounds, and help against malaria.

Population / conservation status

Destruction by humans and livestock, landscape domestication, collection of frogtooths for commercial and scientific purposes, and local fishing by diverting a stream to another channel appear to be important factors in the decline of the species population.

The species is listed in the IUCN International Red Data Book, the Red Data Books of Kazakhstan and China. The abundance of the species varies from year to year, even within one stream.

Literature:

1. Keys to amphibians and reptiles of the fauna of the USSR. Textbook. manual for students of biol. specialties ped. in-tov. M., "Education", 1977.415 p. with ill.; 16 l. silt

2. A.G. Bannikov, I.S. Darevsky, A.K. Rustamov. Amphibians and reptiles of the USSR. Publishing house "Mysl", Moscow, 1971

3. S.L. Kuzmin. Amphibians of the former USSR. Moscow: KMK Scientific Publishing Association. 1999.298 pp., 49 tables, 119 figures, 44 maps, 126 colors. Photo.

4. Chirikova M.A., Kazenas V.L. Amphibians and Reptiles. Series "Animals of Kazakhstan in photographs". - Almaty, 2015.-- 135 p.

5. Ananyeva N.B., Borkin L.Ya., Darevsky I.S., Orlov N.L. Amphibians and reptiles. Encyclopedia of the Nature of Russia. - M: ABF, 1998. - 576 p.; 58 col. ill.

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