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The paper reports the results of the first skeletochronological study of age structure and distinguishing characteristics of growth in the triploid toad Bufotes baturae, inhabitant of Sasyk-Bulak hot spring in the Pamir Mountains (3797 m a.s.l.). Minimal and maximum ages of males of the species were three and seven years, respectively. The age of females ranged from three to six years. Mean age for both sexes was 4.0 years. The majority of males (46.2%) were three years old, most females (58.8%) were four years old. The age of sexual maturity was reached after three hibernations (46% in males and 24% in females). The majority of toads breed once at the age of three or four years. Only few (18% in females and 23% in males) individuals in this population were older. Harsh high-altitude cold desert conditions and limited food resources may cause high mortality of the toads. The correlation between the minimal age at sexual maturity and the degree of dryness of climate was demonstrated among species of the genus Bufotes. As a rule, toads which live in more humid climatic conditions mature earlier. Perhaps, this explains that substantial part of semi-aquatic individuals of B. baturae in the hot spring mature at earlier age (3 years) than other polyploid species (4 – 5 years) that inhabit arid environments. In both sexes of B. baturae, growth rate was similar to that of other closely related high-mountain species, diploid B. latastii and triploid B. pseudoraddei.

In the Talysh Mountains, the marsh frog, Pelophylax ridibundus (Pallas, 1771), increases its distribution due to human activity. In the mountain forest belt, frogs inhabit flowing ponds with cold spring water. These reservoirs are characterized by a stable temperature regime: the water in them is kept at the level of 10 – 12°C in winter and does not fall below 6°C, and in summer does not rise above 18°C. Probably, the cold flow water of ponds in the mountain-forest belt of Talysh can cause some features of growth and maturation for P. ridibundus. The aim of our work was to study the features of the structure of growth layers including the variation in degree of expression of lines of arrested growth (LAGs) of the marsh frogs in ponds with cold flow water. Frogs were collected in the upper part of the Tangeru River gorge in Sym village of Astara District of Azerbaijan (480 m a.s.l.) in August 2018. In total, we studied skeletochronologically 8 females and 9 males. In contrast to the results of the tubular bones studies in the marsh frog presented in earlier works, the studied individuals are characterized by a more complex and diverse structure in the cross section of shin bones. All the revealed diversity of this structure can be divided into three groups. To the first group are relatively rare cases in which there are growth layers with wintering LAGs and additional growth layers but without additional LAGs. The second group includes more frequent cases in which there are growth layers not only with wintering LAGs but with additional LAGs differing discretely from wintering LAGs. The third group includes the rarest cases where there are growth layers with wintering LAGs and with additional LAGs without discrete difference from wintering LAGs. The revealed high variable structure of growth layers and distinctiveness of LAGs in P. ridibundus can be explained by unusual temperature regime in habitat of studied population and the existence of several activity period during a year. The most continuous period of low temperatures (February and March) corresponds to formation hibernation LAGs and dark rings in growth layers. Besides, period from early December to late January may be so cold that frog growth retard sufficiently or stop completely. The formation of more dark parts of growth layers or even several additional LAGs can correspond to this period.

The paper provides the first data about age structure and growth of the Zamda toad, Bufotes zamdaensis (Boulenger, 1882), from the Himachal Pradesh State (India). The study of age structure of toads was carried out using skeletochronology. The minimal and maximal ages in males of B. zamdaensis were 4 and 7 years, respectively, with mean age of 5.4 years. The majority of males (60%) were 5 years old. The age in females ranged from 5 to 9 years with mean value of 6.1 years. The majority of females (71%) were 5 – 6 years old. Males of B. zamdaensis can reach maturation after four winterings and females after five winterings. Unlike closely related species B. latastii, the growth rate in both sexes does not decrease significantly after the 1st and 2nd wintering and remains high after the 3rd and 4th wintering.

The paper provided the first data about age structure and growth of the Lataste’s toad, Bufotes latastii (Boulenger, 1882), from the Jammu and Kashmir State (India). The study of age structure of toads was carried out using skeletochronology. The minimal and maximal ages in males of B. latastii were 3 and 10 years, respectively, with mean age of 6.0 years. The majority of males (70%) were 5 or 6 years old. The age in females ranged from 4 to 10 years with mean value of 5.9 years. The majority of females (71%) were 4 – 6 years old. Males of B. latastii can reach maturation after three winterings and females after four winterings. The body length increment in males is 3.6 times, whereas in females is 3.7 – 4.0 times. After maturation, the growth rate is retarded and the individuals of different ages did not differ in its body length. In spite of maximal age of 10 years in both sexes, the largest male was 5 years old and the largest female was 4 years old.

Geographical differences and the structure of intrapopulation phenotypic variation in metamorphs’ life-history traits from 6 spatially distant populations of Rana temporaria were studied. In frogs from northern populations, heritability of larval period duration, growth rate, and size at metamorphosis was relatively low. Growth rate and size at metamorphosis in laboratory frogs were significantly higher than in those collected in nature, whereas the larval period, in turn, was lower. The revealed differences within and between populations represent a counter-gradient variation. The genetic and phenotypic correlations by pairwise comparisons these three traits were similar (both in magnitude and sign) in all populations, with the exception of one population from Kamchatka. This population was successfully introduced 10 years ago from the Moscow region to the habitat with the minimal duration of activity season. The genetic correlation between body size at metamorphosis and larval period was significantly negative. Thus the response to shortening of activity season was not only the growth rate increase but decrease in larval period, partially at the expense of metamorph size. Refs 6. Tables 2.