Miniature, Burrowing Squamates

 

The repeated evolution of similar, specialized anatomy in many different groups of unrelated animals provides an important opportunity to investigate the factors that shape the major differences we see in skeletal structure. The specialized, shared skull shapes found across head-first burrowing vertebrates that use their heads as a digging tool are an example of such convergence. It has been proposed that these head-first burrowers, from snakes to amphibians, which also tend to be miniaturized, converged on a similar skull shape because of interconnected limitations resulting from similar pressures such as the functional requirements of digging, shared features of vertebrate skull growth, and existing anatomical features inherited from ancestors. To test this hypothesis, most of my own work centers on uropeltid snakes and strange limbless or limb-reduced, extinct early tetrapods in the group Lepospondyli. However, colleagues include Michelle Stocker, who focuses on amphisbaenians (worm lizards), and Hillary Maddin, who studies living caecilians (limbless amphibians) and other extinct early tetrapods. So far, my research projects and those of my students have included new descriptions of the skull of uropeltid snakes and lepospondyls, comparative anatomy and phylogenetics of uropeltids with a focus on variation within species, ear and brain evolution related to miniaturization and burrowing, and finite element analysis of uropeltid skulls to asses strain on cranial bones.