Patterns of girdle shape and their correlates in Australian limb-reduced skinks

The evolution of limb reduction in squamates is a classic example of convergence, but the internal morphological patterns associated with it are unexplored. To provide insights into the biomechanical and developmental consequences of transitions to limb reduction, we use geometric morphometrics to examine the morphology of pectoral and pelvic girdles in 90 species of limb-reduced skinks and their fully limbed relatives. Clavicle shapes converge towards an acute anterior bend when forelimbs are lost but hindlimbs are retained — a morphology typical of sand swimmers. This may either indicate functional adaptations to locomotion in fine substrates, or a developmental consequence of complete limb loss. The shape of limb-bearing elements of both girdles (coracoid and pelvis) instead closely mirrors limb reduction, becoming more simplified as undulation replaces limbed locomotion. Integration between girdles decreases in taxa lacking elements of the forelimbs but not hindlimbs, indicating dif..., , , # Patterns of girdle shape and their correlates in Australian limb-reduced skinks

[https://doi.org/10.5061/dryad.mw6m9065d](https://doi.org/10.5061/dryad.mw6m9065d)

## Description of the data and file structure

This R pipeline and associated files were written by Marco Camaiti (and coauthors). It is meant to extract shape information from landmark coordinates of lizard (skink) girdles. The specific usage of the associated files is included and explained in the pipeline itself. The tree file for the phylogenetic tree used for these analyses can be accessed at [https://doi.org/10.1016/j.ympev.2015.10.009](https://doi.org/10.1016/j.ympev.2015.10.009 \"Persistent link using digital object identifier\"). The full citation for that paper is Zheng, Y., & Wiens, J. J. (2016). Combining phylogenomic and supermatrix approaches, and a time-calibrated phylogeny for squamate reptiles (lizards and snakes) based on 52 genes and 4162 species. *Molecular phylogenetics and evolution*, 94, 537-547.

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