Current Address: Biodiversity Research Center, 1345 Jayhawk Blvd., Lawrence, Kansas 66045.
EVIDENCE FOR REPEATED ACQUISITION AND LOSS OF COMPLEX BODY-FORM CHARACTERS IN AN INSULAR CLADE OF SOUTHEAST ASIAN SEMI-FOSSORIAL SKINKS
Article first published online: 9 MAY 2011
© 2011 The Author(s).
Volume 65, Issue 9, pages 2641–2663, September 2011
How to Cite
Siler, C. D. and Brown, R. M. (2011), EVIDENCE FOR REPEATED ACQUISITION AND LOSS OF COMPLEX BODY-FORM CHARACTERS IN AN INSULAR CLADE OF SOUTHEAST ASIAN SEMI-FOSSORIAL SKINKS. Evolution, 65: 2641–2663. doi: 10.1111/j.1558-5646.2011.01315.x
- Issue published online: 1 SEP 2011
- Article first published online: 9 MAY 2011
- Accepted manuscript online: 11 APR 2011 05:27AM EST
- Received September 04, 2010, Accepted March 24, 2011
- Ancestral state reconstruction;
- body-form evolution;
- Dollo's law;
Evolutionary simplification, or loss of complex characters, is a major theme in studies of body-form evolution. The apparently infrequent evolutionary reacquisition of complex characters has led to the assertion (Dollo's Law) that once lost, complex characters may be impossible to re-evolve, at least via the exact same evolutionary process. Here, we provide one of the most comprehensive, fine-scale analyses of squamate body-form evolution to date, introducing a new model system of closely related, morphologically variable, lizards. Our phylogenetic results support independent instances of complete limb loss as well as multiple instances of digit and external ear opening loss and re-acquisition. Even more striking, we find strong statistical support for the re-acquisition of a pentadactyl body form from a digit-reduced ancestor. Our study reveals that species of the genus Brachymeles exemplify regions of morphospace (body plans) previously undocumented in squamates. Our findings have broad, general implications for body-form evolution in burrowing vertebrates: whatever constraints have shaped trends in morphological evolution among other squamate groups (excluding Bipes) have been lost in this one exemplary clade. The results of our study join a nascent body of literature showing strong statistical support for character loss, followed by evolutionary re-acquisition of complex structures associated with a generalized pentadactyl body form.