Abstract
Lines of arrested growth (LAGs) appearing in bone sections are useful for age estimation. They also indicate the past growth process in amphibians in temperate zones. Several back-calculation formulae (BCFs) use LAGs to estimate an individual's body size at an earlier time based on the current body size. In order to evaluate the validity of these BCFs, we conducted a mark-recapture and skeletochronological study of female Rana japonica in Higashi-Hiroshima, Japan, from 1995 to 1999. The body sizes of 31 recaptured frogs were back-calculated using eight different BCFs and were compared with the frogs' actual body sizes as measured at the previous capture. The most accurate estimation was made by the simplest BCF (Dahl-Lea method) without any regressions between body size and bone diameter; that is, Li=Lc(Di/Dc) (L: snout-vent length, D: bone diameter, c: at the time of capture [recapture], i: at the i-th winter).
