Age Determination of Frogs and Toads (Amphibia, Anura) from North‐western Europe

Abstract

Age was determined in three anuran species inhabiting a temperate oceanic climate ( Rana temporaria, Bufo calamita and Bufo bufo ) by means of the histological structure of the phalanges. Narrow, haematoxylinophilic lines were visible in these, and evidence from the examination of subadults and frog ( R. temporaria ) recaptures showed the lines to be annual. The validity of using the lines as age indicators was tested most extensively on natural frog populations and the effects of endosteal resorption were not found to be significant. The evidence for this conclusion was provided directly by recapture data and indirectly by an analysis of histological measurements made on the phalanges.