Mesoderm-derived: Limb Formation
Stage of Development: Embryo
This is a Stage 16 Anolis carolinensis or green anole lizard embryo. The embryo is quite advanced and is only a few stages away from hatching. Skeletal tissues, like cartilage, are being remodeled and some bones are undergoing endochondrial ossification. The hindlimbs and forelimbs have limb joints and are flexed at a 90 degree angle. Digit joints, like the metacarpophalangeal joints, are not yet visible.
Lamellae and claws are present. Epidermal papillae and scale anlagen cover the body. Melanophores are diffuse, partially pigmenting the surface of the embryo. The lower jaw is well defined and tooth precursors are beginning to develop inside the mouth. The mesencephalon has greatly decreased in size. Eyelids cover the well-developed iris.
Sanger, T.J., Losos, J.B., Gibson-Brown, J.J. A developmental staging series for the lizard genus Anolis: A new system for the integration of evolution, development, and ecology. Journal of Morphology, 2008, 269:129-137.