Age and body size of Salamandrella keyserlingii (Caudata: Hynobiidae): a difference in altitudes, latitudes, and temperatures

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Why is it important?

The debate surrounding Bergmann’s rule (i.e., body size of animals is predicted to be larger in cooler environments) is still open for ectotherms. By analyzing data for 27 populations within the geographic range of the Siberian salamander from 43 to 69 °N across a 2900-km long latitudinal gradient, we have detected intraspecific tendency to decrease body size with increased latitude from 43 to 57 °N and increase size from 57 to 69 °N or to decrease body size with decreased temperature from 8 to –7 °C and increase size from –7 to –15 °C. This pattern does not follow the intraspecific extension of Bergmann’s rule and may follow the converse of Terentjev’s optimum rule, i.e., a rule formulated to be an inverted-U shaped curve between increased latitude (or decreased temperature) and increased body size.