Geographic variation in body size and life-history traits in Bosca's newt (Triturus boscai)

Body size of newts from five populations of Triturus boscai was measured an d the age of the newts was estimated using skeletochronology. Variation in adult body size was observed throughout the range of the species, with larg est individuals of the southernmost populations being smaller than the smal lest adults of the northern localities. Sexual dimorphism in body size was detected in all populations studied. A tendency towards older mean ages was also observed from southern to northern populations. The age of youngest b reeders, modal age at which growth slows, and mode of the age structure sho wed geographic variation, with the greatest differences in life-history tra its being between northernmost and southernmost populations, survival being optimized in the north by delaying either the age of maximum reproductive output or sexual maturity. The variation observed may have been due to evol utionary changes, though more extensive information on genetic and morpholo gical interpopulational differences is needed to support a taxonomic differ entiation.