Diet evolution in Tropiduridae lizards: ecological relations and phenotypic associations

Abstract

Evolutionary associations between diet and cranial morphology have been described in a wide array of squamate lineages. Data on osteological proportions and overall skull shape are frequently interpreted in relation to diet specialization, leaving possible associations with the evolution of generalist habits (dietary plasticity/flexibility) relegated in the literature. The present project aims to test the hypothesis of associations between morphological patterns in the skull and the degree of diet flexibility. Such associations will be measured in three complementary dimensions: seasonal, ontogenetic and populational. The project will be implemented using species from the family Tropiduridae (Squamata), a lineage with a high diversity of food habits and considerable availability of information for ecology and diet. Patterns of skull shape will be inferred from linear measures obtained in specimens available at herpetological collections. Species will be classified according to the degree of flexibility based on information available in the literature following three parameters: 1) the variation in the composition of the diet between seasons (seasonality), 2) the variation in the composition of the diet between juveniles and adults (ontogeny), 3) the variation in the composition of the diet between localities where animals were collected (populational). Depending on time and resources, clutches of Tropidurus catalanensis, a highly flexible species in terms of diet composition, will be collected and the juveniles will be raised in captivity under different diet compositions, in order to screen for phenotypic differences triggered by ingestion of different food types during ontogeny. (AU)