Head shape evolution in Gymnophthalmidae: does habitat use constrain the evolution of cranial design in fossorial lizards?

Abstract

Habitat usage comprises interactions between ecological parameters and organismal capacities, and the selective pressures that ultimately determine the outcome of such processes in an evolutionary scale may be conflicting when the same morphological structure is recruited for different activities. Here, we investigate the roles of diet and locomotion in the evolution of cranial design in gymnophthalmid lizards and test the hypothesis that microhabitat use drives head shape evolution, particularly in head‐first burrowers. Morphological factors were analysed in relation to continuous ecological indexes (prey hardness and substrate compactness) using conventional and phylogenetic approaches. Results suggest that the evolution of head morphology in Gymnophthalmidae was shaped under the influence of microhabitat use rather than diet: burrowers have shorter heads with lower rostral angulation, independently of the prey consumed. Food preferences appear to be relatively conserved throughout the phylogeny of the group, which may have permitted the extensive radiation of gymnophthalmids into fossorial microhabitats.

Microhabitat use and diet of Anotosaura vanzolinia(Squamata: Gymnophthalmidae) in a Caatinga area, Brazil

“…However, Rodrigues (2003), characterized the species of the Caatinga as relictual, because A. vanzolinia demonstrated a preference for habitats with dense vegetation and a microenvironment of milder temperatures. Northeastern Brazil is composed of residual reliefs, which serves as evidence of present and former integration between the Atlantic forest and the Caatinga, as shown by Borges-Nojosa & Caramaschi (2003). These authors highlight the importance of these ombrophile areas to the relictual fauna.…”

“…The morphology is primarily correlated with its fossorial habit and consequently with the type of microhabitat that the species chooses to utilize, suggesting they use more of the physical properties among substrates (Grizante 2009). The evolution of the morphology and limb reduction has been suggested to be adaptive for fossorial locomotion by subterranean crawl or locomotion by ripples in environments with leaf litter (Grizante 2009, Roscito 2010, Barros et al 2011.…”

“…Other prey are restricted in movement (insect larvae) or immobile (insect eggs), indicating the opportunism of the species. The conservation of food preferences in the Gymnophthalmidae might have permitted the extensive radiation of the family into fossorial microhabitats (Barros et al 2011).…”

Reptiles Del Bosque Seco Estacional en El Caribe Colombiano: Distribución De Los Hábitats Y Del Recurso Alimentario

“…Sin embargo se sugiere un estudio de dieta de la especie que tenga en cuenta de una forma más detallada la estacionalidad del bosque. La preferencia de presas pequeñas, suaves y de movimientos lentos en la dieta de B. talpa podría deberse a su fácil captura y digestión; como se ha demostrado en otras especies de Gymnophthalmidos y amphisbaenas esto puede obedecer a un rasgo histórico que parece haber favorecido la evolución del grupo de excavadores (Barros et al, 2011).…”

Evolution of erythrocyte morphology in amphibians (Amphibia: Anura)

“…The PGLS analyses incorporate phylogenetic information into generalized linear models. They offer a powerful method for analyzing continuous data, and have been applied to estimate the evolutionary model and the relationships among the traits of interest (BARROS et al 2011, WARNE & CHARNOV 2008. In PGLS, the strength and type of the phylogenetic signal in the data matrix can be accounted for by adjusting branch length transformations, which show the degree of phylogenetic correlation in the data.…”