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Bufo verrucosissimus
Caucasian Toad
family: Bufonidae

© 2010 David Tarkhnishvili (1 of 4)

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Conservation Status (definitions)
IUCN (Red List) Status Near Threatened (NT)
See IUCN account.
CITES No CITES Listing
Other International Status Data Deficient
National Status Red Data Book of Azerbaijan and Russia.
Regional Status Red Data Book of Krasnodar Region, Russia. All narrow ranged subspecies seem to be Rare.

   

Description
The Caucasian toad is very similar to Bufo bufo, but differs by its larger size (ranging from 70-190 mm snout-vent lenght), body proportions, tongue shape, skin texture and coloration and more pronounced sexual dimorphism in body size. In the Caucasian toad, males do not have a resonator, or a tarsal fold. In addition, the Caucasian toad has 2nd and 3rd toes with paired subarticular tubercles. The dorsal skin contains large rounded tubercles, and the ventral skin has small tubercles. The dorsal surface is gray or light-brown, with dark spots. Longitudinal stripes, more or less developed, are present on parotoids. The belly is gray or yellowish. The male differs from female by a considerably smaller body size and other characters similar to those involved in the sexual dimorphism of B. bufo. However, there is no sexual dimorphism in coloration.

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Azerbaijan, Georgia, Lebanon, Russian Federation, Syrian Arab Republic, Turkey

View distribution map using BerkeleyMapper.
The species inhabits the Caucasus (former USSR and Turkey) and Northwestern Iran (Elburz Mountains). The range is highly fragmented. The main part of the distribution is confined by the mountains with the level of annual precipitation of 1000 mm and higher. The range is subdivided into three parts: Great Caucasus, the northern slopes of the Caucasus Minor and Talysh-Elburz Mountain System. Several species are recognized, but their validity needs further clarification. Bufo verrucosissimus inhabits the southern slopes of the Main Caucasian Ridge from the Black Sea shore eastwards to Akhaldaba Village on the Kura River, and then by a narrow band along the Main Caucasian Ridge to Eastern Azerbaijan. The northern range margin corresponds to the Main Caucasian Ridge. On the western slope of Lazistanian Ridge, the distribution extends towards Turkey (Rize Vilayet). In Russia, in the valley of the Belaya River, the subspecies penetrates the northern slope of the Main Caucasian Ridge towards the settlements to about 44oN. Bufo verrucosissimus turowi inhabits a narrow territory in the foothills of the northern slope of the Main Caucasian Ridge (Russia) from the confluence of the Rivers Urushten and Malaya Laba to Yatygvart Town the canyon of the Bolshaya Laba River. Bufo verrucosissimus circassicus inhabits a narrow territory at the northwestern of the Great Caucasus: from Krepostnaya Village on the northern slope of the Main Caucasian Ridge towards Gelendzhik Town on the shore of the Black Sea.

According to allozyme data, Bufo bufo from the Anatolian part of Turkey is closer to B. verrucosissimus, in comparison with B. bufo or B. spinosus (from Tunisia, for example). Therefore, we consider B. verrucosissimus but not B. bufo to inhabit this part of Turkey, as well as Syria and Lebanon (though as of Sept. 2008 there are not yet published records from Lebanon). Also, despite Baloutch and Kami (1995) providing a record for B. verrucosissimus in northern Iran, Litvinchuk has studied photos provided by Kami, and has concluded that these specimens are Bufo eichwaldi (Litvinchuk, pers. comm. 2008).

The Caucasian Toad lives in mountain coniferous, mixed and deciduous forests upward to the subalpine belt. The toad prefers wet, shaded sites in forests, bushlands, their edges and glades. Holes under logs and stones are used as hiding places. Some specimens were found in hollows of slantwise staying trees. Reproduction occurs in clear, flowing or semi-flowing water, mainly in brooks, springs and small rivers, but also in puddles, ponds, lakes and seepage pools.

Life History, Abundance, Activity, and Special Behaviors
The population density reaches 70-140 specimens per hectare. However, populations are localized and total number of the toad seems to be low. Hibernation occurs in holes and burrows in soil from September - December to February - April. Reproduction occurs from February to June (in mountains to August), depending on the weather and the elevation, but usually it occurs in April - May. Amplexus is pectoral. The sexual dimorphism in body size is highest among the toads of the Palearctic, and the males are much smaller than females. It is supposed that the advantage of smaller males and large females consists of the ability of amplectant pairs of moving up to two weeks in search of a breeding site.

The clutch contains 870-10500 eggs arranged in 3 rows. The spawn consists of two long, to 12 m, strings. Metamorphosis occurs in June - August. Sexual maturity is attained at 2-7 years (in females later than in males); maximum longevity is estimated at 10 years.

Tadpoles feed mainly on detritus and algae. Recently metamorphosed toadlets eat mainly Collembola of different families, small beetles and ants. Adult toads eat a wide variety of invertebrates with a prevalence of Myriapoda, caterpillars, Coleoptera and Formicidae. The main part of their diet consists of terrestrial crawling invertebrates.

Trends and Threats
Destruction of forests and drying of wetlands by people result in declines of populations of this hygrophilous forest species.

Relation to Humans
Cases of meaningless killing of the toad by people and mortality on roads are also known. However, it occurs in anthropogenic landscapes: in the forested edges of settlements, near roads, ditches in tea plantations and even in a garden in the city. The toad sometimes uses artificial water bodies for reproduction, including tanks for fish breeding.

Possible reasons for amphibian decline

Habitat modification from deforestation, or logging related activities
Disturbance or death from vehicular traffic

References
 

Baloutch, M. and Kami, H. G. (1995). Amphibians of Iran. Tehran University Publishers, Tehran.  

Bannikov, A. G., Darevsky, I. S. and Rustamov, A. K. (1971). Zemnovodnye i Presmykayushchienya SSSR [Amphibians and Reptiles of the USSR]. Izdatelistvo Misl, Moscow.  

Bannikov, A. G., Darevsky, I. S., Ishchenko, V. G., Rustamov, A. K., and Szczerbak, N. N. (1977). Opredelitel Zemnovodnykh i Presmykayushchikhsya Fauny SSSR [Guide to Amphibians and Reptiles of the USSR Fauna]. Prosveshchenie, Moscow.  

Basoglu, M. and Ozeti, N. (1973). Turkiye Amphibileri. Ege Univ, Bornova-Izmir.  

Gasc, J. P. , Cabela, A., Crnobrnja-Isailovic, J., Dolmen, D., Grossenbacher,K., Haffner, P., Lescure, J., Martens, H., Martinez Rica, J. P.,Maurin, H., Oliveira, M. E., Sofianidou, T. S., Vaith, M., and Zuiderwijk, A. (1997). Atlas of Amphibians and Reptiles in Europe. Societas Europaea Herpetologica and Muséum National d’Histoire Naturelle, Paris.  

Kuzmin, S. L. (1995). Die Amphibien Russlands und angrenzender Gebiete. Westarp Wissenschaften, Magdeburg.  

Kuzmin, S. L. (1999). The Amphibians of the Former Soviet Union. Pensoft, Sofia-Moscow.  

Nikolsky, A. M (1936). Fauna of Russia and Adjacent Countries: Amphibians (English translation of Nikolsky, 1918, Faune de la Russie et des Pays limitrophes. Amphibiens. Académie Russe des Sciences, Petrograd, USSR). Israel Program for Scientific Translations, Jerusalem.  

Nikolsky, A. M. (1906). Herpetologia Rossica. Mémoires de l'Académie Impériale des Sciences de St.-Pétersbourg, Série 8, Phys.-Math, Vol. 17, Sofia, Moscow.  

Nöllert, A. and Nöllert, C. (1992). Die Amphibien Europas. Franckh-Kosmos Verlags-GmbH and Company, Stuttgart.  

Tarkhnishvili, D. N. and Gokhelashvili, R. K. (1999). ''The amphibians of the Caucasus.'' Advances in Amphibian Research in the Former Soviet Union, 4, 1-233.  

Terent'ev, P. V. and Chernov, S. A (1965). Key to Amphibians and Reptiles [of the USSR]. Israel Program for Scientific Translations, Jerusalem.



Written by Sergius L. Kuzmin (ipe51 AT yahoo.com), Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow
First submitted 1999-09-30
Edited by Vance Vredenburg, Kellie Whittaker (2008-09-19)



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Citation: AmphibiaWeb: Information on amphibian biology and conservation. [web application]. 2014. Berkeley, California: AmphibiaWeb. Available: http://amphibiaweb.org/. (Accessed: Oct 20, 2014).

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