A developmental staging series for the lizard genus Anolis: A new system for the integration of evolution, development, and ecology

Abstract

Vertebrate developmental biologists typically rely on a limited number of model organisms to understand the evolutionary bases of morphological change. Unfortunately, a typical model system for squamates (lizards and snakes) has not yet been developed leaving many fundamental questions about morphological evolution unaddressed. New model systems would ideally include clades, rather than single species, that are amenable to both laboratory studies of development and field-based analyses of ecology and evolution. Combining an understanding of development with an understanding of ecology and evolution within and between closely related species has the potential to create a seamless understanding of how genetic variation underlies ecologically and evolutionarily relevant variation within populations and between species. Here we briefly introduce a new model system for the integration of development, evolution, and ecology, the lizard genus Anolis, a diverse group of lizards whose ecology and evolution is well understood, and whose genome has recently been sequenced. We present a developmental staging series for Anolis lizards that can act as a baseline for later comparative and experimental studies within this genus.

Repeated modification of early limb morphogenesis programmes underlies the convergence of relative limb length inAnolislizards

“…(b) Relative growth of embryonic limbs By stage 10, 'early digital web reduction' [45] (figure 1), the relative size of the long bones is well established. Significant differences in intercept occur between the Cuban species' forelimbs and hindlimbs, and among the hindlimbs of Jamaican species ( figure 6; table 1).…”

“…These species were chosen because of their relative ease of care in captivity and the rate at which they lay eggs. Detailed methods of embryo collection have been described elsewhere [45,46].…”

“…[47,48]), we used snout-to-vent length (SVL) as a standard measure of body size. For embryological comparisons, we collected one to three individuals per stage for each of the four species examined, from the early stages of digital webbing reduction (stage 9/10) through hatching (stage 19 [45]). Combined with the post-hatching series, this represents nearly the entire period of long bone skeletal development and growth (figure 1).…”

Developmental regulation of hemoglobin synthesis in the green anole lizard Anolis carolinensis

“…We sampled early, mid-and late-stage embryos corresponding to stages 5, 5/6, 11 and 17 of Anolis development ( Fig.2) (Sanger et al, 2008a). Relative to most avian eggs, A. carolinensis eggs are laid at a relatively advanced embryonic stage, represented by stage 5.…”

“…We sampled just before this time at stage 17. Lizard husbandry and embryo collection were performed in accordance with guidelines approved by the Institutional Animal Care and Use Committee of Harvard University , and details are provided by Sanger et al (Sanger et al, 2008a;Sanger et al, 2008b). Briefly, sexually mature A. carolinensis lizards were collected from the wild and purchased from Candy's Quality Reptiles (La Place, LA, USA).…”