Evolution 2019: What Shapes the Shape of Lesser Antillean Anole Claws?

Organismal performance frequently depends on multiple phenotypic traits in the context of the environments these organisms inhabit. Earlier this year, we saw the  study  by Yuan and colleagues examining the integration of claw and toe pad morphological evolution related to structural habitat partitioning of the Greater Antillean anoles. At Evolution 2019, Michael Yuan, a PhD student in Dr. Marvalee Wake’s Lab at U.C. Berkeley, presented work delving into the next steps of this line of questioning investigating the morphological evolution of claw and toe pad morphological evolution in Lesser Antillean anoles.

Do the patterns of claw and toepad evolution found on the Greater Antilles hold for the divergent lineages found in the Lesser Antilles?

Yuan collected data characterizing toe pad width; lamella number;  claw height, length and width and claw geometric morphometric data on species found in the Lesser Antilles. He found that the total variation in claw and toe pad morphology was similar between the Lesser Antillean and Greater Antillean anoles. To potentially explain this variation, he explored environmental variables, seeking to explain if macrohabitat is associated with claw and toe pad morphology. He found that on single species islands, there was a strong relationship between habitat and toe curvature, leading to a pattern between macrohabitat and claw shape that is disrupted by competitive interactions on the two-species islands. To investigate microhabitat as a potential predictor of this variation, he asked if claw and toe pad traits are correlated with perch height. Unlike his study in the GA anoles, he found no relationship between claw and toe morphology and perch height, unless it was broken down by series. Functional traits are predictably correlated with vertical habitat in the bimaculatus series (anoles that colonized the Lesser Antilles from the Greater Antilles), but not in the roquet series (anoles that colonized the lesser Antilles from mainland South America).