The Herpetological Journal

pp.21-27

Authors: C. Diaz-paniagua And J. A. Mateo

Abstract: Body size of newts from five populations of Triturus boscai was measured and the age of the newts was estimated using skeletochronology. Variation in adult body size was observed throughout the range of the species, with largest individuals of the southernmost populations being smaller than the smallest 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 breeders, modal age at which growth slows, and mode of the age structure showed geographic variation, with the greatest differences in life-history traits 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 evolutionary changes, though more extensive information on genetic and morphological interpopulational differences is needed to support a taxonomic differentiation.

Keywords: geographical variation, newt, life history, Triturus boscai