Assessing the origin of trait variation during evolutionary history is an important first step in understanding evolutionary diversification. Here, we tested the influence of shared ancestry and... Show moreAssessing the origin of trait variation during evolutionary history is an important first step in understanding evolutionary diversification. Here, we tested the influence of shared ancestry and climate, and the interplay of both, on the variation of ten life history traits in Triturus newts. We showed that (1) climate alone has driven the evolution of variation in live life history traits, (2) phylogenetic signal partly explains the variation in two traits (vitellus diameter and snout-vent length of larvae at metamorphosis), and (3) the interplay of shared ancestry and climate explains the variation in one trait (snout-vent length of larvae at metamorphosis). This study highlights the coarse-grained influence of shared ancestry and climate on the structure of phenotypic trait variation in Triturus and provides a handle for more detailed, fine grained studies on the evolution of phenotypic trait variation. Show less
We characterized the adult body form of the crested newt (Triturus cristatus superspecies) and explored its evolution. From seven morphometric traits, we determined that body size, interlimb... Show moreWe characterized the adult body form of the crested newt (Triturus cristatus superspecies) and explored its evolution. From seven morphometric traits, we determined that body size, interlimb distance and head width define the body form. None of the morphometric traits showed a phylogenetic signal. Three body-shape morphotypes (Triturus dobrogicus + T. cristatus, Triturus carnifex + Triturus macedonicus and Triturus karelinii + Triturus arntzeni) and three body-size morphotypes (T. dobrogicus, T. cristatus and all other crested newts) could be recognized. The ancestral phenotype (a large body with a short trunk and a wide head) characterized T. karelinii and T. arntzeni. Triturus carnifex and T. macedonicus had a somewhat different phenotype (large body and wide head, accompanied by mild body elongation). The most derived phenotype included body size reduction and more pronounced body elongation in T. cristatus and, especially, in T. dobrogicus. Body elongation occurred by trunk lengthening but not head and tail lengthening. Additionally, contrary to other tetrapods, evolutionary axis elongation in crested newts was followed by a decrease in body size. We advocate the hypothesis that ecology drives the evolution of body form in crested newts. Show less