Most Important Papers (Population ecology / Genetics of the Amphibians of the Caucasus)
• D. Tarkhnishvili, 2004. Genebis kaleidoskopi mtian kundzulze (Kaleidoscope of Genes on a Mountainous Island: the Animal World of the Caucasus and its evolution). Buneba-Print, Tbilisi (in Georgian).
• D. N. Tarkhnishvili & R. V. Tartarashvili, 1987. On the development of spotted pigmentation in some Salamandridae. Zoologicheskij Zhurnal, 66 (9): 1328-1338. Abstract
• D. N. Tarkhnishvili & R. G. Mamradze, 1989. Modification of Caucasian brown frog's phenotype under the influence of high temperature. Bulletin of the Academy of Sciences of the Georgian SSR, 135 (2): 437-440. Abstract
• D. Tarkhnishvili, 1993. Anurans of Borjomi Canyon : clutch parameters and guild structure. Alytes, 11(4): 140-154 . Abstract
• D. Tarkhnishvli & I. A.. Serbinova, 1993. The Ecology of the Caucasian Salamander (Mertensiella caucasica Waga) in a Local Population. Asiatic Herpetological Research, 1993, 5: 147-165. Abstract
• D. Tarkhnishvili & R. Gokhelashvili, 1994. Amphibian assemblages of Trialeti ridge, Georgia . In: Amphibian Populations of Commonwelth of Independent States, S. L. Kuzmin, C. K. Dodd, Jr & M. M. Pikulik (eds), Moscow 1994, 125-135. Abstract
• D. Tarkhnishvili & R. Gokhelashvili, 1994. Age structure of six Georgian anuran populations and its dynamics during two consecutive years. Herpetozoa, 1994, 7 (1/2): 11 - 18. Abstract
• D. Tarkhnishvili & R. Gokhelashvili, 1994. Preliminary Data of the Age Structure of a Mertensiella caucasica Population. Mertensiella, 1994, 4: 327 - 334. Abstract
• D. Tarkhnishvili, 1994. Interdependences between Populational, Developmental and Morphological Features of the Caucasian Salamander, Mertensiella caucasica. Mertensiella, 1994, 4: 315 - 325. Abstract
• D. Tarkhnishvili, 1994. Breeding of the toad Bufo verrucosissimus: sexual dimorphism and shifting spawning sites. Amphibia-Reptilia, 1994, 15: 191-198. Abstract
• T. Chubinishvili, R. K. Gokhelashvili, & D. N. Tarkhnishvili, 1995. Population ecology of the Caucasian parsley frog (Pelodytes caucasicus Boulenger) in the Borjomi Canyon . Russian Journal of Herpetology, 1995, 2 (2): 79 - 86. Abstract
• D. Tarkhnishvili, 1995. On the Inheritance of the mid-dorsal Stripe in the Iranian Wood Frog (Rana macrocnemis). Asiatic Herpetological Research, 1995, 6: 120-131. Abstract
• D. Tarkhnishvili, 1996. The distribution and ecology of the amphibians of Georgia and the Caucasus : a biogeographical analysis. Zeitschrift fur Feldherpetologie 1996, 3: 16-196. Abstract
• S. L. Kuzmin & D. Tarkhnishvili, 1996. Food Niche Dimensions in a Caucasian Amphibian Assemblage. Advances in Amphibian Research in the Former Soviet Union , 1996, 1: 117-129. Abstract
• D. Tarkhnishvili & R. Gokhelashvili, 1996. A contribution to the ecological genetics of frogs: age structure and frequency of striped specimens in some Caucasian populations of the Rana macrocnemis complex . Alytes, 14 (1): 27-41. Abstract
• D. Tarkhnishvli & I. A.. Serbinova, 1997. Normal development of the Caucasian Salamander (Mertensiella caucasica). Advances in Amphibian Research in the Former Soviet Union , 1997,. 2: 13-30. Abstract
• D. Tarkhnishvli & I. A.. Serbinova, 1998. Giant Larvae of the Caucasian Salamander (M ertensiella caucasica). Advances in Amphibian Research in the Former Soviet Union , 3: 187-191. Abstract
• D. Tarkhnishvili, 1998. Phylogenetic Reconstruction on the Local Population Level: Use of Characters under Selection. Advances in Amphibian Research in the Former Soviet Union , 1998, 3: 35-42. Abstract
• D. Tarkhnishvili & R. Gokhelashvili, 1999. Spatial structure and regulation of a population of the brown frog Rana macrocnemis in Georgia . Herpetological Journal, 1999, 9: 169-177. Abstract
• D. Tarkhnishvili, J. W. Arntzen, & R. S. Thorpe, 1999. Morphological variation in brown frogs from the Caucasus and the taxonomy of the Rana macrocnemis group. Herpetologica, 55(3): 406-417. Abstract
• D. Tarkhnishvili & R. Gokhelashvili, 1999. The Amphibians of the Caucasus . Advances in Amphibian Research in the Former Soviet Union 1999, Volume 4 : 1-239 ( treatise). Abstract
• D. Tarkhnishvili, R. S. Thorpe, & J. W. Arntzen, 2000. Pre-Pleistocene Refugia and Differentiation between Populations of the Caucasian Salamander (Mertensiella caucasica). Molecular Phylogenetics and Evolution, 14 (3): 414-422. Abstract
• D. Tarkhnishvili, A. Hille & W. Boehme, 2001. Humid forest refugia, speciation an secondary itrogression between evolutionary lineages: differentiation in a Near Eastern brown frog, Rana macrocnemis. Biological Journal of the Linnean Society 74: 141-156. Abstract
• D. Tarkhnishvili, A. Kandaurov & Alexander Bukhnikashvili, 2002. Declines of amphibians and reptiles in Georgia during the 20th century: virtual vs. actual problems. Zeitschrift fur Feldherpetologie 9: 89-107. Abstract
On the development of spotted pigmentation in some Salamandridae . Zoologicheskij Zhurnal, 1987, 66 (9): 1328-1338.
D. N. Tarkhnishvili & R. V. Tartarashvili
Analysis was performed on the nature of pigmentation changes in three species of newts, spotted and Caucasian salamanders starting with hatching (newts) or larvae development (salamanders). Pigmentation dynamics in larval development is similar for rent species and even for different genera of Salamandridae. However different intensity and duration of this process govern the distribution of yellow pigment in metamorphosis and development of definitive pigmentation.
Modification of Caucasian brown frog's phenotype under the influence of high temperature . Bulletin of the Academy of Sciences of the Georgian SSR, 135 (2): 437-440.
D. N. Tarkhnishvili & R. G. Mamradze
Some features of frog phenotype (for example, striata and punctata ) are shown as simple inheritable ones. Laboratory experiments with Rana macrocnemis have shown that connection between striped and non-striped, spotted and non-spotted specimens is changed if the temperature of tadpole development increases.
Anurans of Borjomi Canyon : clutch parameters and guild structure. Alytes, 1993, 11(4): 140-154 .
David N. Tarkhnishvili
http://www.herplit.com/contents/Alytes.html
Spawn clutches of six anuran species, inhabiting Borjomi Canyon in central Georgia , were examined: Rana macrocnemis, Bufo [bufo] verrucosissimus, Pelodytes caucasicus, Rana ridibunda, Bufo viridis and Hyla arborea . The first three species constitute the guild of "Brown Anura" associated with forest and have the same spawning mode: females deposit a single clutch per year. The other three species prefer open areas and have multiple spawns. Brown Anura have larger eggs, and probably lower fecundity, than other amphibians of similar body size. Within the Brown Anura guild, different species show the same relationships of fecundity, egg size and clutch size with body length. Within the guild, lower fecundity and smaller eggs in species with smaller body size are compensated by rapid maturation. Among guilds, egg size is inversely correlated with fecundity.
The Ecology of the Caucasian Salamander (Mertensiella caucasica Waga) in a Local Population. Asiatic Herpetological Research, 1993, 5: 147-165.
David N. Tarkhnishvli & Irina. A. Serbinova
The different aspects of ecology of Mertensiella caucasica Waga, 1876 were investigated in a local population from Borjomi Canyon (central Georgia ) for five years (1985-1990). The aspects of the species' life cycle were more precisely determined. The main fecundity is about 16.9 eggs per female. There are about 2 years in a period from egg deposition (June to first half of July) to the end of metamorphosis in nature. Animals have spent most of the time in shelters after metamorphosis. They appear on the ground surface at night during the breeding period. Commonly the adults don't retreat to a great distance from population localities. Localities are situated in comparatively small plots (100-300m) along the streams. Estimation of adult animal number showed that the population consists of 1189 specimens (1989). Annual adult survival is higher than known values of most amphibians (approaches 0.77). Larval survival is 0.27-0.32 in the second year of life. 'The characteristics of demography (especially, low renewal rates) and spatial restriction in localities depends mostly on subtle constitution of the species (which is a result of allometric growth specifics). The small recent geographical range of M. caucasica is explained as a result of morphological and ecological peculiarities. General morphological constitution limits adaptive possibilities of any particular representative of the European salamander tribe. This is an explanation of quite high ecological similarity of M. caucasica and Chioglossa lusitanica.
Key words: Amphibia, Caudata, Salamandridae, Mertensiella caucasica, Caucasus Mountains, Georgia , population ecology.
Amphibian assemblages of Trialeti ridge, Georgia . In: Amphibian Populations of Commonwelth of Independent States, S. L. Kuzmin, C. K. Dodd, Jr & M. M. Pikulik (eds), Moscow 1994, 125-135.
David N. Tarkhnishvili & Ramaz K. Gokhelashvili
We have analyzed the amphibian assemblages of Trialeti Ridge, eastern and central Georgia . Eleven resident amphibian species form six types of assemblages, the majority of which are not clearly separated from one another geographically. The species composition of each assemblage is discussed in relation to habitat structure. The results permit us to predict which amphibian species may I found in particular habitats through a combination of geobotanical and geographical information.
Age structure of six Georgian anuran populations and its dynamics during two consecutive years. Herpetozoa, 1994, 7 (1/2): 11 - 18.
Ramaz K. Gokhelashvili & David N. Tarkhnishvili
During two consecutive years, the age distribution of the reproductive portion of coexisting populations of Pelodytes caucasicus, Hyla arborea, Bufo verrucosissimus, B. viridis, Rana macrocnemis and R. ridibunda was studied using skeletochronological methods. Significant interspecific differences were found for the mean age of adults and population turnover rates, while the minimum age of maturation was two years for most species. The youngest mean age was found in P. caucasicus and R. ridibunda, the oldest in female Bufo spp. Turnover rates were higher in early maturing species.
Key words : Amphibians, Bufo verrucosissimus, Bufo viridis, Hyla arborea, Pelodytes caucasicus, Rana macrocnemis, Rana ridibunda; skeletochronology, population ecology, longevity, sexual maturity, mortality, life cycle, turnover rates; Georgia (Caucasus).
Preliminary Data of the Age Structure of a Mertensiella caucasica Population . Mertensiella, 1994, 4: 327 - 334.
David N. Tarkhnishvili & Ramaz K. Gokhelashvili .
Age structure of the local population of the Caucasian salamander (Mertensiella caucasica) was examined using skeletochronology. Age of adult animals ranges between 12 and 26 years; modal age class is 18 years. Annual mortality of adult males was estimated as 23 %, judging by correlation of different age classes. It corresponds to a value obtained earlier by using capture-recapture techniques. Taking into account fecundity and larval mortality, the period of population number duplication is reached after 10 years, if the growth rates remain exponential. Probably larval development covers 2 to 4 years of life, depending on developmental conditions, in the first 3 to 8 years after metamorphosis growth must be very slow, judging by the disposition of year rings and comparison of age and size in juvenile salamanders. The beginning of the growth period and maturation is variable. Perhaps the individual variation of growth dynamics stabilizes the number of adult animals in populations.
Interdependences between Populational, Developmental and Morphological Features of the Caucasian Salamander, Mertensiella caucasica . Mertensiella, 1994, 4: 315 - 325 .
David Tarkhnishvili .
Peculiarities of the demography and spatial structure of populations of the Caucasian salamander ( Mertensiella caucasica Waga) make this species highly vulnerable to the variety of environmental conditions. These peculiarities include low intrinsic growth rates of the populations, resulting in a low fecundity and late maturation. High dependence upon mountain streams result in a low carrying capacity, small size of local populations, and a high degree of isolation of the separate populations. These features can be connected with tile thin body shape of the salamanders. Body shape variation among European salamander species (Salamandrinae ) determines their reproductive mode and peculiarities of their life cycles. Slender body shape prevents evolution of viviparity and simultaneously limits fecundity. Perhaps the slim shape of the body evolved as a result of larval adaptation to development in running waters. Shortcomings of this adaptation become obvious in metamorphosed salamanders. The life mode M . caucasica allows only narrow habitats with a high local stability.
Key words: Caucasian salamander , life mode , intrinsic growth rates , fecundity , mortality , rheophilous habitats , reproductive mode , daintiness.
Breeding of the toad Bufo verrucosissimus: sexual dimorphism and shifting spawning sites . Amphibia-Reptilia, 1994, 15: 191-198
David N. Tarkhnishvili .
http://www.gli.cas.cz/SEH/Journal/Volume15.htm
The Colchic toad (Bufo verrucosissimus) inhabits wet mountain forests of Caucasia and breeds in small and unstable slow streams and seepage pools. Pair formation usually takes place on land. Amplexing couples search for new breeding sites every year; there is little site fidelity. Active searching for breeding sites is facilitated by the small size of males; the species is highly dimorphic, males having a mean body length of 70-85 mm, females a length of 100-130 mm. If a larger, more permanent water body appears in a region, reproductive tactics change and males-wait for females around the pond. These generalizations are supported by data collected from 1989-1993. There was an inverse correlation between body size of females and males in amplexing pairs.
Population ecology of the Caucasian parsley frog (Pelodytes caucasicus Boulenger) in the Borjomi Canyon . Russian Journal of Herpetology, 1995, 2 (2): 79 - 86.
A. T. Chubinishvili, R. K. Gokhelashvili, & D. N. Tarkhnishvili .
Certain aspects of the population ecology of Pelodytes caucasicus were studied. Breading season of the Caucasian parsley frog lasts from the second half of May up to the end of September. One female deposits from 100 up to 750 eggs, There is a positive correlation between body size of the female and fecundity. As usual tadpoles stay in basins until following spring. Body size of the metamorphosing tadpoles depends on physical characters of the basin and larvae density. Survivability of tadpoles from egg until metamorphosis in different basins, varies from 0.5 up to 10%, Individuals attain sexual maturity when 2 - 3 years old. Males of the Caucasian parsley frog can live up to 6 years. We did not found females, elder than 4 years old. The population renews more then by half annually. Population dynamics of the Caucasian parsley frog in general corresponds to the typical model of "sources and sinks."
Key words : Pelodytes caucasicus, Population ecology, Age-distribution, Phenology of Reproduction, Survivability.
On the Inheritance of the mid-dorsal Stripe in the Iranian Wood Frog (Rana macrocnemis). Asiatic Herpetological Research, 1995, 6: 120-131 .
David N. Tarkhnishvili
The frequency of the phenotype Striata (presence of a light mid-dorsal stripe) is often used in
population investigations of anurans. Simple hereditary nature of this character was established experimentally. Nevertheless, animals with a poorly developed stripe can be found in populations of some species, together with non-striped specimens and clear Striata in the frog, Rana macrocnemis. The expression of the mid-dorsal stripe varies continually. Poorly striped frogs prevail in some populations. We examined the distribution among froglets obtained from seven R. macrocnemis pairs whose eggs and larvae developed at 18, 25, and 29°C. Non-striped froglels predominate in the offspring of non striped parents and 100 in the offspring of striped frogs. Non the less, all phenotype spectra, from specimens with a clear stripe to non-striped animals, are represented in almost all groups. The morph distribution is quire continual the character varies as a quantitative one. When the developmental temperature increases, the frequency of morph predominating in optimal conditions (18°C) declines with the increasing frequency of poorly striped froglets. Modifications of the character under the influence of thermal conditions shadows genetic specifics of sibling group. Similar influence of conditions on the morph distribution in froglets was found in natural populations. Morph distribution among newly emerged froglets affects morph distribution of adults in the populations two years later.
Key words: Amphibia, Anura, Ranidae, Rana macrocnemis, inheritance, Georgia .
The distribution and ecology of the amphibians of Georgia and the Caucasus : a biogeographical analysis. Zeitschrift fur Feldherpetologie 1996, 3: 16-196.
David N. Tarkhnishvili
http://www.number19.free-online.co.uk/v9no4.html
The republic of Georgia is situated in the central-western part of the Caucasus Isthmus in between the Black and Caspian Seas . The country has thirteen amphibian species: Triturus karelinii, T. vittatus ophryticus, T. vulgaris lantzi, Mertensiella caucasica, Pelobates syriacus, Pelodytes caucasicus, Bufo verrucosissimus, B. viridis, Hyla arborea schelkownikowi, H. savignyi, Rana macrocnemis, R. camerani, R. ridibunda. Three species (M. caucasica, P. caucasicus, B. verrucosissimus) and two subspecies (T. vulgaris lantzi, H. arborea schelkownikowi) are endemic to the Caucasus . Four species (T. vittatus, H. savignyi, R. macrocnemis, R. »camerani«) are restricted to the Near East region. Two (T. karelinii, P. syriacus) are distributed throughout south-eastern Europe and the Middle East , while two (B. virdis, R. ridibunda) have a wide Eurasian distribution. The analysis of amphibian distribution patterns, both within and outside the Caucasus region, leads to the recognition of five zoogeographic groups that in term can be arranged into the larger units of (1) amphibians of the Near East and (2) amphibians of the Caucasian zoogeographic district. Two pairs of closely related species (or subspecies) (Hyla and Rana) produce hybrid zones in Georgia .
Key words: Amphibian distribution, amphibian ecology, Caucasus , Georgia , hybrid zones, biogeography.
Food Niche Dimensions in a Caucasian Amphibian Assemblage . Advances in Amphibian Research in the Former Soviet Union , 1996, 1: 117-129.
Sergius L. Kuzmin & David N. Tarkhnishvili .
http://www.herplit.com/contents/USSR.html
Abstract : We studied food resource partitioning in an assemblage of seven amphibian species (Mertensiella caucasica, Pelodytes caucasicus, Bufo verrucosissimus, B. viridis, Hyla arborea schelkownikowi, Rana macrocnemis, and R. ridibunda) living in Georgia , Borjomi District, near the village of Akhaldaba . Interspecific correlations of mean number of prey per stomach with predator body size were significant for juveniles but not for adults. Adults eat prey that are more variable in size. Intraspecific correlations were rarely significant. For amphibians, patterns of resource partitioning in the assemblage differ in niche dimension depending on age class and/or species. Juveniles form a separate group within the assemblage based on the size of their prey. Niche differences by taxonomic and ecological composition of prey seem to be influenced primarily by peculiarities of morphology, nearness to water, and foraging tactics. Amphibian assemblages that consist of different species but have similar morphological and ethological structure should display similar patterns of resource partitioning.
A contribution to the ecological genetics of frogs: age structure and frequency of striped specimens in some Caucasian populations of the Rana macrocnemis complex . Alytes, 1996, 14 (1): 27-41
David N. Tarkhnishvili & Ramaz K. Gokhelashvili
http://www.herplit.com/contents/Alytes.html
Four populations of Caucasian brown frogs (Rana macrocnemis) from different elevations and different mountain systems (Great and Minor Caucasus) were studied. In populations from the Minor Caucasus, the percentage of striped frogs increases with elevation, but not in the Great Caucasus. At the same time, age at sexual maturity in Caucasus Minor populations does not differ between forest and subalpine populations. It is suggested that in this region the increasing proportion of genetically striped frogs is the main adaptation preventing a decrease of reproductive potential with elevation. In the brown frogs metapopulation inhabiting the Great Caucasus, such a mechanism is absent.
Normal development of the Caucasian Salamander (Mertensiella caucasica). Advances in Amphibian Research in the Former Soviet Union , 1997,. 2: 13-30.
David N. Tarkhnishvili & Irina A. Serbinova .
http://www.herplit.com/contents/USSR.html
We present tables showing the normal development of the Caucasian Salamander Mertnesiella caucasica). Peculiarities of early development, body proportions, growth, and formation of limbs and coloration pattern are discussed.
Giant Larvae of the Caucasian Salamander (M ertensiella caucasica) . Advances in Amphibian Research in the Former Soviet Union , 1998, 3: 187-191.
David N. Tarkhnishvili & Irina A. Serbinova .
http://www.herplit.com/contents/USSR.html
An isolated population of the Caucasian Salamander (Mertensiella caucasica) inhabits a small plot of native vegetation in the Batumi Botanical Garden . Adjaria , Georgia . Larvae from this locality reach a snout-vent length of 41 mm and a total length of 97 mm. This is significantly larger than in other Localities of this species. A large size in prometamorphic stages characterises all specimens found in the locality and supposedly reflects the genetic specificity of the population.
Phylogenetic Reconstruction on the Local Population Level: Use of Characters under Selection . Advances in Amphibian Research in the Former Soviet Union , 1998, 3: 35-42.
David N. Tarkhnishvili
http://www.herplit.com/contents/USSR.html
If there is information about the genetic nature and selective advantage of a phenetic marker, this marker can be useful for testing phylogeographic hypotheses. If the frequency of a character differs in two populations with extensive gene flow, differences can be sustained by selection. Dependent on the degree of differences, one can test the hypothesis whether interacting populations have a common origin or are derived from different ancestral lineages. This situation is tested on the example of Caucasian brown frogs (Rana macrocnemis group) in which populations can markedly differ in the frequency of a mid-dorsal stripe even if they inhabit adjacent localities and are characterised by an extensive gene flow.
Spatial structure and regulation of a population of the brown frog Rana macrocnemis in Georgia . Herpetological Journal, 1999, 9: 169-177.
David N. Tarkhnishvili & Ramaz Gokhelashvili .
http://www.number19.free-online.co.uk/v9no4.html
A spatially structured population of the brown frog Rana macrocnemis was studied over seven consecutive years in the valley of a small mountain river. Frogs spawned in numerous temporary pools and puddles situated along the river bed. The overall number of reproductive females varied between 868 and 1146 during the course of study. The population had a 'source- sink' spatial structure: 88% of all froglets metamorphosed in just a few of the sites. Density- dependent mortality of larvae did not significantly affect the overall number of metamorphs. However, the variation in size of the whole population and of one of the two sub-populations was density-dependent. The most important cause of regulation appears to be density-dependent dispersal of juveniles from sources to adjacent sinks. Sinks often had a high number of 'traps' - large well-illuminated pools that frogs prefer for egg deposition but which desiccate during the course of larval development more often than the deep and cold, less attractive breeding sites.
Key words: Rana macrocnemis, frog populations, spatial ecology.
Morphological variation in brown frogs from the Caucasus and the taxonomy of the Rana macrocnemis group. Herpetologica, 1999, 55(3): 406-417
David N. Tarkhnishvili, Jan W. Arntzen, & Roger S. Thorpe.
http://www.inhs.uiuc.edu/cbd/HL/journals/H_55_3.html
Multivariate analysis of body proportions, skin texture, and coloration characteristics of brown frogs (Rana macrocnemis and R. 'camerani') from 14 Georgian populations confirms the existence of two, geographically distinct groups of populations. Frogs in the first group (R. macronemis) are characterized by a smooth skin, a pale spotted pattern, absence of a mid-dorsal stripe, and a small inner metatarsal tubercle. Frogs in the second group (known as R. camerani) possess a rugose skin, a conspicuous pattern of dorsal spots, a mid-dorsal stripe with contrasting borders, and a large metatarsal tubercle. The first group occurs in the uplands of the Great Caucasus and other forested areas while the second group occurs in the treeless uplands of the Near East . A stepped cline exists between them, with parallel variation in eight morphological characters. Other characters analyzed vary independently of the cline. Fully diagnostic (fixed) morphological characters separating the groups were not observed. Some characters previously used for taxonomic purposes are shown to be associated with local ecological conditions. We conclude that R. macrocnemis is a single, though polytypic, species composed of two interbreeding evolutionary lineages.
Key words: Brown frogs , Caucasus , Clinal variation , Coloration , Multivariate statistics , Near East , Rana macrocnemis, Taxonomy , Transition zone.
The Amphibians of the Caucasus . Advances in Amphibian Research in the Former Soviet Union
1999, Volume 4 : 1-239 ( treatise)
http://www.pensoft.net/notes/1654.stm
http://www.herplit.com/contents/USSR.html
Editorial Preface. As stated in the instructions for Authors, "Advances in Amphibian Research in the Former Soviet Union" accepts not only papers of a "standard" length, but also large treatises up to 85 pages in length. Such works may, in fact, represent small books. In such cases, due to their high quality and interest to the scientific community, special issues of the journal may be dedicated to them. This is the case with the following overview by D. N. Tarkhnishvili and R. K. Gokhelashvili on the Caucasian amphibians.
The Caucasian region possesses a unique amphibian fauna, which is also one of the richest in the former Soviet Union . Although it has attracted the attention of both professional and amateur zoologists for many years, only a few extended reviews are avail- able. The first (and only) review embracing the whole of the Caucasian area was published by A. M. Nikolsky in 1913. Subsequent works of this type have covered only particular regions. Some of these reviews are brief, though others contain more detail. Therefore, a single work which generalised the data, without the 'loss of important details, seemed to be necessary.
The following treatise by David N. Tarkhnishvili and R. K. Gokhelashvili aims to fulfill this requirement. Although it is not possible to put into one small book all of the data published during the last 170 years' study of the Caucasian amphibians, the bibliography is nonetheless fairly large and used in full. This book embraces both the Caucasus itself (i.e. the North Caucasus and Transcaucasia), but also Precaucasia, i.e. the plains adja- cent to the Caucasus from the north. The morphology, systematics, distribution and ecology of each species are characterised in detail. The treatise contains much original material collected by the authors during many years of work, which is not published elsewhere. This applies also to the pictures: many of them (e.g. the developmental stages of some species) are unique and will be important for further comparisons of the Caucasian species with their allopatric relatives. The results and discussion are aimed at the professional, but this does not make the book unusable by others who are interested in the Caucasian amphibians and the natural history of the Caucasus .
This overview fills a considerable gap in our knowledge on the zoology of the Caucasus .
It can also serve as a good guide to the amphibian fauna of the region. Sergius L. Kuzmin, 9 September 1998
Pre-Pleistocene Refugia and Differentiation between Populations of the Caucasian Salamander (Mertensiella caucasica). Molecular Phylogenetics and Evolution, 2000, 14 (3): 414-422
David N. Tarkhnishvili, Roger S. Thorpe, and J. W. Arntzen
http://www.idealibrary.com/links/doi/10.1006/mpev.1999.0718
A 350-bp fragment of the mitochondrial cytochrome- b gene was sequenced in the Caucasian salamander, Mertensiella caucasica, representing 10 populations from across its range along the Black Sea coast. Five haplotypes were discovered among 65 fragments analyzed, differing at 2-50 positions. The highest differentiation between haplotypes was observed In animals from the eastern part of the species' range (Borjomi) compared to those from the remainder of the species' range. Randomly amplified nuclear DNA revealed a pattern of spatial genetic variation similar to that of the mitochondrial genome. M. caucasica, as currently known, represents two evolutionary lineages that evolved independently, perhaps since the lower Pliocene. These lineages represent taxa, possibly to be described as species, distributed in the Borjomi area in central Georgia and northeastern Turkey . The multivariate analysis of morphological data did not reveal significant differences between the taxa. However, substantial morphological differentiation was observed within both lineages, showing parallel patterns in body proportions and coloration patterns. This variation is possibly associated with extant ecological conditions. Salamanders with reduced pigmentation from southwestern Georgia were not genetically distinguishable from neighboring populations.
Key Words: amphibians; Caucasus; cytochrome- b gene; historical biogeography; Mertensiella caucasica; morphological stasis; multivariate morphometrics; phylogey; RAPD's.
Humid forest refugia, speciation an secondary itrogression between evolutionary lineages: differentiation in a Near Eastern brown frog, Rana macrocnemis . Biological Journal of the Linnean Society 2001, 74: 141-156 .
David Tarkhnishvili, Axel Hille & Wolfgang Boehme.
http://www.idealibrary.com/links/doi/10.1006/mpev.1999.0718
Brown frogs of the complex Rana macrocnemis demonstrate various degrees of differentiation between the two widespread forms, macrocnemis and camerani, in different parts of Anatolia, the Caucasus Isthmus and northern Iran . In order to reveal whether or not the forms represent monophyletic evolutionary lineages, we analysed the graphic distribution of characters of external morphology, alleles at three polymorphic allozyme loci and mitochondrial DNA haplotypes. All three character sets showed a highly congruent pattern in a limited area of humid forests in the south-west Caucasus . Frogs from this area (form macrocnemis) represent a monophyletic lineage which forms a narrow hybrid zone with populations of camerani inhabiting the southern Caucasus and north-east Turkey . However, in other parts of the group's range, hybridization between the two lineages resulted he merger of forms and the formation of a clinal pattern of variations. The role of landscape-dependent diversifying selection in the evolution of the group is discussed. Conceptual difficulties in delimiting the borders of species are pointed out.
Key words : geographic variation - coloration pattern - allozymes - mitochondrial DNA - hybrid zones - landscape-dependent selection - genealogical concordance.
Declines of amphibians and reptiles in Georgia during the 20th century: virtual vs. actual problems. Zeitschrift fur Feldherpetologie 2002, 9: 89-107
David Tarkhnishvili, Andrei Kandaurov & Alexander Bukhnikashvili
http://www.number19.free-online.co.uk/v9no4.html
Currently, 12 amphibian and 54 reptile species are known for Georgia . We analysed 437 records of amphibian and reptile localities that belong to the period before 1930, and compared them with the current distribution of the same species. The data derive from publications from the last 40 years, and the author's observations. 49 out of 437 old species/habitats could not be confirmed, in spite of regular recent analysis of a location. However, the analysis demonstrates that the reason species an absent is wrong species identification by earlier authors, nomenclatural changes, wrong or imprecise localisation, or miss-labelling, rather than real extinction. In only 20 cases must an extinction of a species from a locality be assumed. This applies mainly to amphibian and reptile species that are dependent on dry, steppe-like, or shrubby landscapes, which are found in Georgia at the northern edge of their ranges. The northern border of the distribution of Pelobates syriacus, Eirenis collaris, Malpolon monspessulanus, and Vipera lebetina retreated 8-50 km southwards during the 20th century; the upper altitudinal borders of the distributions of Lacerta strigata, Typhlops vermicularis and Eryx jaculus in eastern Georgia have been displaced 200-300 m downwards. Triturus karelinii and Bufo viridis disappeared from the south-western (Ajarian) fragment of the Georgian Black Sea coast. It is remarkable that extinction was assumed most often for species that depend on relatively dry treeless landscapes and never for species that depend on mesophylic forest habitats.
Key words. Amphibia, Reptilia, Georgia , decline, 20 th century.