Meeting Abstract
The evolution of a snake-like body shape in terrestrial animals is thought to be an adaptation for burrowing, yet this remains largely untested. A corollary of this assumption is that one would expect a trade-off between surface running and burrowing performance. Brachymeles skinks include species ranging from pentadactyl and lizard-like to limbless and snake-like with intermediate forms, and phylogenetic evidence suggests that Brachymeles has evolutionary lost and then re-evolved limbs. This begs the question of why would a burrowing animal re-evolve limbs that were likely lost to enhance burrowing performance? One hypothesis is that re-evolved limbs may differ functionally from ancestral limbs and allow an animal to break the trade-off between surface running and burrowing. We tested this hypothesis using 12 species of Brachymeles and one outgroup taxon. We related the number of digits (a proxy for how snake-like a species is) to running and burrowing average and maximum velocity, and maximum acceleration. We also related each performance measure for running and burrowing to quantify performance relationships. Preliminary analyses suggested positive relationships between running and burrowing velocity measures, but a trade-off between running and burrowing acceleration. However, there were positive relationships between numbers of digits and both running and burrowing performance. Together, our results suggested that more lizard-like species were better at both modes of locomotion. In general, there was mixed evidence for a trade-off between the running and burrowing, and no relationship between the existence of such a trade-off and body shape.
