Meeting Abstract
Lizards are morphologically diverse, exhibiting a wide range of sizes and shapes. Among these shapes, the snake-like form has evolved independently at least 25 times. Among many of these lizards, the snake-like form is thought to be an adaptation for fossoriality. Since these animals penetrate the substrate headfirst when burrowing, head shape variation may also play an important role in burrowing. We aimed to test what aspects of body and head shape affect burrowing performance in 12 species of Lerista. Lerista are a diverse clade of skinks endemic to Australia, which exhibit snake-like bodies, lizard-like bodies, and multiple intermediate forms. We recorded high-speed videos of burrowing behavior for 12 species of Lerista on fine and coarse sand substrates from the dorsal aspect. The species in our dataset encompassed six different digit morphs, ranging from robustly limbed with four digits on each limb to nearly completely limbless, the majority of body shape variation in Lerista. We tracked a point on the pelvic girdle to calculate maximum velocity and acceleration and average velocity as measures of burrowing performance. We hypothesized that traits associated with snake-like bodies would positively affect all of our measures of burrowing performance regardless of substrate coarseness. Our findings suggest that aspects of body shape do not affect either measure of burrowing velocity on either of the substrates. Maximum acceleration slightly increased with relative body length, relative hind limb length, and relative body width on the coarser substrate but decreased on the finer substrate. These results may indicate that in Lerista, snake-like body shape only affects some aspects of burrowing performance and that different body shapes are adapted to different substrates.
