## Code files: #### 01_trait_evolution.R Code for running the comparative methods applied to the 559-species phylogeny (Pagel's test, M*k* models, stochastic character mapping, and weighted model averaging). Corresponds to Fig. 3 in the paper. #### 02_buccal_size_ANOVA.R Code for testing whether mouthbrooders and/or winnowers have larger buccal cavities than species that exhibit neither behavior. Includes two different approaches for accounting for body size (including length as a covariate and using phylogenetic residuals). Corresponds to Fig. 4 in the paper. #### 03_buccal_shape_PGLS.R Phylogenetic generalized least squares (PGLS) analysis of buccal cavity shape, including PCA for visualization (Fig. 5 in the paper). #### S01_buccal_area_vs_volume.R Validation of 2D buccal cavity sagittal section area as a proxy for 3D buccal cavity volume, as measured in 20 $\mu$CT scans. Corresponds to supplementary section S01. #### S02_trait_evolution_sensitivity analyses.R Sensitivity analyses of mouthbrooder classifications for comparative results. Corresponds to supplementary section S02. #### S03_two_block_pls.R Two-block partial least squares analyses of buccal cavity shape and head shape for the dataset for examining association between these two features. ## Data files: #### McGee2020_tree.tre and McGee2020_tips*.csv: 559-species tree trimmed from the full cichlid tree in McGee et al. (2020) used for phylogenetic analyses, and the corresponding behavioral classifications for the tips. #### buccal_areas.csv Buccal cavity sagittal section areas. #### ext_gmdf.RDS and int_gmdf.RDS Geomorph dataframes for internal (buccal) and external (head) shape data, including phylogenies and behavioral states. #### procrustes_INT.Rdata and procrustes_EXT.Rdata Procrustes fits of shape data. #### 'images' folder Images for morphometric analyses. 'External' folder contains images before dissection (from which external cranial morphology was measured), and 'internal' contains images of buccal cavity dissections. Other .RDS files are generated by the code files within the supplement, but existing versions have been uploaded for users who wish to run downstream analyses from these files. See code comments for explanations.