Age determination of Daruma pond frog, Rana porosa brevipoda from Japan towards its conservation (Amphibia: Anura)

Abstract

The age of a vulnerable frog, Rana porosa brevipoda from Japan was estimated using the now classical technique of skeletochronology. The mean age did not differ between the sexes but males were smaller in body size than females. Sexual maturity was attained in the fall of the year of metamorphosis in males and in the breeding season of the next year in females, and both sexes began to breed in the next year of metamorphosis. Both sexes similarly had minimum longevity of four years. The population age composition showed a rapid decrease in number of frogs with the increase of age. Growth parameters differed between sexes and males grew more rapidly and sexually matured at a smaller size than females. We comment on the peculiar pattern of postmetamorphic survival curves in R. porosa brevipoda as a threatened species. We also discuss the reason of decline in this species and suggest a measure of conservation.