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The role of post‐natal ontogeny in the evolution of phenotypic diversity in Podarcis lizards
Author(s) -
PIRAS P.,
SALVI D.,
FERRARA G.,
MAIORINO L.,
DELFINO M.,
PEDDE L.,
KOTSAKIS T.
Publication year - 2011
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/j.1420-9101.2011.02396.x
Subject(s) - heterochrony , biology , ontogeny , allometry , evolutionary biology , morphometrics , morphology (biology) , convergent evolution , zoology , phylogenetics , ecology , genetics , gene , biochemistry
Understanding the role of the developmental pathways in shaping phenotypic diversity allows appreciating in full the processes influencing and constraining morphological change. Podarcis lizards demonstrate extraordinary morphological variability that likely originated in short evolutionary time. Using geometric morphometrics and a broad suite of statistical tests, we explored the role of developmental mechanisms such as growth rate change, ontogenetic divergence/convergence/parallelism as well as morphological expression of heterochronic processes in mediating the formation of their phenotypic diversity during the post‐natal ontogeny. We identified hypermorphosis – the prolongation of growth along the same trajectory – as the process responsible for both intersexual and interspecific morphological differentiation. Albeit the common allometric pattern observed in both sexes of any species constrains and canalizes their cephalic scales variation in a fixed portion of the phenotypic space, the extended growth experienced by males and some species allows them to achieve peramorphic morphologies. Conversely, the intrasexual phenotypic diversity is accounted for by non‐allometric processes that drive the extensive morphological dispersion throughout their ontogenetic trajectories. This study suggests a model of how simple heterochronic perturbations can produce phenotypic variation, and thus potential for further evolutionary change, even within a strictly constrained developmental pathway.