A skeletochronological study of age and growth in relation to adult size in the water frog Rana epeirotica

The age and growth of individuals in a population of the water frog Rana epeirotica, from northwestern Greece, were studied in 1998 and 1999 using skeletochronology. Analysis of the age structure was based on the enumeration of Lines of Arrested Growth (LAGs) in phalanges. Ages ranged from 1-5 years among 145 males and from 1-5 years among 173 females. The mean snout-vent length was 72.74 +/- 7.96 mm in males and 83.63 +/- 11.73 mm in females. The difference between the sexes in age and size was significant. Endosteal resorption may have eroded away the first LAG in only 9% of the studied individuals and was more frequent in females. Growth of adults was fitted by the Bertalanffy model. The growth coefficient (K) was 0.88 in males and 0.49 in females, reflecting faster male growth between metamorphosis and maturation.