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We applied multivariate analyses to an array of body measures of alpine newt specimens derived from 11 local populations in Greece to describe, analyse and detect patterns and putative causes of within-population and among-population morphometric variation. The observed morphometric variation was partitioned into several independently varying aspects of the external phenotype, frequently following variation patterns in different environmental factors. The size and features of the aquatic habitat were found to affect body size, while altitude was found to affect head-shape variation in both sexes. At the intra-population level, variation in generalized body size and shape was found to be significantly lower when competitive newt species were present in the habitat, indicating stabilizing selection towards a decrease in inter-specific competition. No clear discrimination on body size and shape proportions was detected between the two genetic lineages examined, implying ecogenetic or environmentally induced variation rather than phylogeny. [ABSTRACT FROM AUTHOR]

Multivariate analyses were applied to an array of body measures of smooth newt specimens derived from 14 local populations of two subspecies in Greece, in order to describe, analyse and detect patterns and putative causes of among-population morphometric variation. The two subspecies do not differ morphometrically, in spite of their considerable genetic differentiation. Paedomorphosis explains a significant portion of the observed morphometric differentiation of populations. Differences between the two morphs refer mostly to characters and structures relevant to feeding and locomotion, which might lead to niche segregation and subsequent reduction of intra-population competition. Body size varies in relation to altitude probably as a result of differential developmental processes or as an environmentally induced response to varying predation pressures. Variation of different aspects of the external morphology is correlated both to climatic factors and habitat characteristics. [ABSTRACT FROM AUTHOR]