As I discussed in a previous post, molecular phylogenetics suggests that many lizards evolved to become legless over time. One might wonder if there is any evidence of this legged ancestry during their development. In fact, at least some legless lizards possess limb buds as embryos. One particular example comes from the sheltopusik (Ophisaurus adopus), a legless lizard that is more closely-related to alligator lizards than snakes.
Below are six Ophisaurus embryos at different stages in development . Despite being legless as an adult, you’ll notice that near the tail region there are tiny hindlimb buds (labelled “b”).
For comparison, here is an embryo of a fully-legged anole lizard (Anolis).
During development, the sheltopusik’s hindlimb buds fail to develop fully, though they’re retained as tiny remnants in the adults (they are above the more prominent hemipenes in the image below).
In this way, the development (ontogeny) of the sheltopusik recapitulates its evolutionary history (phylogeny), with its embryos showing a glimpse of its legged past.
Questions for Creationists
Why do you think God would have created legless lizards that have limb buds during development? Is it a coincidence that they are genetically nested within fully-legged lizards? What other evidence might be used to test the hypothesis that legless lizards evolved from legged ancestors?