Sanger, TSeav, S. M.Tokita, MasayoshiLangerhans, R. B.Ross Berry, Lee AnnLosos, JonathanAbzhanov, Arkhat2018-03-212014Sanger, T. J., S. M. Seav, M. Tokita, R. B. Langerhans, L. M. Ross, J. B. Losos, and A. Abzhanov. 2014. “The Oestrogen Pathway Underlies the Evolution of Exaggerated Male Cranial Shapes in Anolis Lizards.” Proceedings of the Royal Society B: Biological Sciences 281 (1784) (April 16): 20140329–20140329. doi:10.1098/rspb.2014.0329.0962-8452http://nrs.harvard.edu/urn-3:HUL.InstRepos:35059699Sexual dimorphisms vary widely among species. This variation must arise through sex-specific evolutionary modifications to developmental processes. Anolis lizards vary extensively in their expression of cranial dimorphism. Compared with other Anolis species, members of the carolinensis clade have evolved relatively high levels of cranial dimorphism; males of this clade have exceptionally long faces relative to conspecific females. Developmentally, this facial length dimorphism arises through an evolutionarily novel, clade-specific strategy. Our analyses herein reveal that sex-specific regulation of the oestrogen pathway underlies evolution of this exaggerated male phenotype, rather than the androgen or insulin growth factor pathways that have long been considered the primary regulators of male-biased dimorphism among vertebrates. Our results suggest greater intricacy in the genetic mechanisms that underlie sexual dimorphisms than previously appreciated.en-USsexual dimorphismevo-devomorphometricsfacial lengthoestrogen signallingJournal Article10.1098/rspb.2014.0329