Novel neuroanatomical integration and scaling define avian brain shape evolution and development

(a) List of taxa sampled for this study, with the exclusion of Alligator and Gallus. Institutional abbreviations: AMNH, American Museum of Natural History, New York, NY, USA; BMNH, British Museum of Natural History, London, UK; FMNH, Field Museum of Natural History, Chicago, IL, USA; KU, University of Kansas, Lawrence, KS, USA; NMNH, National Museum of Natural History, Washington DC, USA; TCWC, Texas Cooperative Wildlife Collection, College Station, TX, USA; TMM, Texas Memorial Museum, Austin, TX, USA; WDC, Wyoming Dinosaur Center, Thermopolis, WY, USA. (b) List of discrete landmarks and density of semi-landmarks for each neuroanatomical region. (c) Phylogenetic signal (Blomberg’s K), allometry, and evolutionary allometry in endocranial shape. Results generated using physignal, procD.lm, procD.pgls functions in geomorph R package v3.2.1 (Adams and Otárola-Castillo, 2013). Results from analysis on globally and locally aligned regions are presented as first and second values within a cell, respectively. Allometry evaluated with log-transformed centroid size of the entire endocast and local region, respectively. ^*, ^**, and ^*** indicate p<0.05, <0.01, and <0.001, respectively, based on 1000 pseudo-replications. (d) Integration within and between locally aligned neuroanatomical regions. Degree of integration is measured by correlation coefficient from two-block partial least-squares analysis (R_PLS; upper off-diagonal) and correlation coefficient (ρ; diagonal, lower off-diagonal) using the R packages geomorph v3.2.1 (Adams and Otárola-Castillo, 2013) and EMMLiv2 v0.0.3 (Goswami and Finarelli, 2016), respectively. Interspecific analyses are phylogenetically corrected using phylogenetic generalized least-squares method. (e) Integration within and among globally aligned neuroanatomical regions. The degree of integration is measured by correlation coefficient from two-block partial least-squares analysis (R_PLS; upper off-diagonal) and correlation coefficient (ρ; diagonal, lower off-diagonal) using the R packages geomorph v3.2.1 (Adams and Otárola-Castillo, 2013) and EMMLi v2 v0.0.3 (Goswami and Finarelli, 2016), respectively. Interspecific analyses are phylogenetically corrected using phylogenetic generalized least-squares method. (f) Integration between neuroanatomical regions using covariance ratios (CR) (Adams, 2016). Degree of integration between globally aligned regional shapes are listed in the upper off-diagonal elements and that of locally aligned regional shapes in the lower off-diagonal elements. Interspecific analyses are phylogenetically corrected using phylogenetic generalized least-squares method. (g) Comparison of integration among neuroanatomical regions using the compare.pls function in the geomorph R package (Adams and Otárola-Castillo, 2013; Adams and Collyer, 2016). ‘+’ and ‘–’ denote greater and lesser integration in Neornithes and Gallus compared to non-avialan coelurosaurs and Alligator, respectively. Integration among species calculated upon phylogenetic correction. ^*, ^**, and ^*** indicate p<0.05, <0.01, and <0.001 (one-tailed), respectively, based on 1000 pseudo-replications. Numbers preceding and following ‘/’ indicate results based on globally and locally aligned data, respectively.