A skeletochronological study on a subtropical, riparian ranid (Rana swinhoana) from different elevations in Taiwan

We estimated the age, longevity, and growth patterns of a subtropical ranid, Rana swinhoana from high (Lishing) and low (Wulai) elevations using skeletochronology. In addition, we also measured body mass and length of frogs from five other localities. Results showed that both snout-vent length and body mass of frogs were significantly correlated with altitudes for both sexes. Frogs of Lishing were significantly larger and older than that of Wulai. We used LAGs to estimate the age and growth of frogs and found that the growth of Wulai frog of both sexes slowed down at an earlier age than that of Lishing frogs. Male and female frogs from Wulai did not exceed 6 and 7 years, respectively, while the maximum age of males and females of Lishing was 7 and 11 years, respectively. Results suggest that the LAGs observed in R. swinhoana correspond to low temperature and/or decreased food availability instead of desiccation during the harsh annual period (November to February). Skeletochronological data suggest that the variations of body size of R. swinhoana among elevations are likely associated with the growth, age at sexual maturity, and longevity.