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. Author manuscript; available in PMC: 2017 Sep 1.
Published in final edited form as: J Evol Biol. 2016 Jul 8;29(9):1873–1878. doi: 10.1111/jeb.12918

Figure 3.

Figure 3

(a) Evolutionary allometry of the cranium in Galliformes obtained from the multivariate regression of shape contrasts onto size contrasts (i.e. log centroid size). (b, c) Expected shape of (b) a small and (c) a large cranium in lateral and top view (top and bottom, respectively). The observed pattern resembles the cranial evolutionary allometric (CREA) ‘rule’ described in mammals and birds where small species display relatively shorter faces and wider braincases than large species. (cranium scan downloaded from http://digimorph.org/). (d) Evolutionary allometry of the cranium in Galliformes obtained from a major axis analysis of beak and braincase size (i.e. centroid size contrasts). The regression slope deviated significantly from 1, indicating the presence of negative allometry (PICs: phylogenetic independent contrasts; CS: centroid size).