Developmental processes, evolvability, and diversification of molar teeth in platyrrhines

BERNAL V.; GONZALEZ P.; D`ADDONA L; PEREZ S. I.

Congreso; European Evo-Devo Conference; 2012

Development of particular organs is controlled by intrinsic growth regulators and systemic factors, which contribute to trait evolvability. Here, we assessed whether a developmental model based on a balance of activators and inhibitors (IC model) accounted for the variation in relative lower molar size among 21 species of platyrrhines, and then, we estimated the association between molar morphology and life history traits. We demonstrated that the fit of molar proportions to IC model depended on the regression model used. Phylogenetic generalized least-squares model, the best-fit regression, was not significantly different from the IC model. Molar proportions concordant with this model were associated with relative neonatal size: species with a smaller proportion of adult weight at birth have a weak IC, resulting in distal molars of a size similar to or larger than the first molars. Callitrichines show agenesis of third molars with higher than expected activation/inhibition ratios. Such variation, not explained by the IC model, was associated with lower postnatal growth rates. This study highlights that changes in the relative amount of inhibitors/activators facilitated the main evolutionary trend of relative molar size in platyrrhines, and that processes regulating local dental development and species-specific growth patterns were evolutionary associated.