论文部分内容阅读
A skeletochronological study was conducted for the age,longevity and growth of a Rana nigromaculata population in northeastern Sichuan,China.Of 139 specimens,119 (68 males and 51 females) exhibited distinct arrested growth lines in phalanges.Age at first reproduction was found to be two years of age for males and three for females.Maximum longevity was estimated to be at least six years in males and seven years in females.Average age did not differ between males and females.Breeding females were significantly older than breeding males.Females were larger in body size and heavier in body mass than males.Age was not correlated with body size and body mass in males,but a significant correlation was found among age,body size and body mass in females.The growth curve appeared significantly different between the sexes,with a higher growth rate throughout life and a larger asymptotic size in females.Moreover,analysis of the growth model indicated that the population studied was relatively stable.