Figure 9
Phylogenetic principal component analysis based on anatomical network parameters. Patterns of topospace occupation are represented using convex hulls. See legend in (b) for symbols used throughout all panels. (a) Biplot showing overall topospace composition. Red arrows indicate the contribution of each network parameter to the first two phylogenetic principal components. Taxa are labelled using the first three letters of their respective genus, or the first letter of the genus and first two letters of the specific epithet (see Supplementary Table S1). Representative specimens are indicated in dark blue. (b) Distribution of higher taxa across topospace. Non-snake lizards, anomalepidids, booid-pythonoids, and caenophidians occupy generally distinct regions, whereas typhlopoids, leptotyphlopids, and anilioids overlap extensively. (c) Distribution across topospace of jaw morphotypes proposed by Strong et al.15. (d) Distribution of habitat types across topospace. Fossorial and non-fossorial taxa occupy distinct regions, although these regions do overlap somewhat. Semi-fossorial taxa occupy an intermediate region overlapping broadly with both other habitats. (e) Distribution of size classes across topospace. Miniaturized and non-miniaturized taxa both occupy large regions of topospace; these regions are generally distinct but do exhibit noticeable overlap. (f) Distribution of taxa when considering size and habitat simultaneously. Miniaturization and fossoriality together define a more distinct region of topospace than when either phenomenon is considered individually, reflected by reduced overlap between opposing regions (i.e., miniaturized–fossorial versus non-miniaturized–non-fossorial). N total number of nodes, K total number of connections, D density of connections, C mean clustering coefficient, L mean shortest path length, H heterogeneity of connections, P parcellation. Axis labels are consistent throughout all panels. Analyses performed and plots generated in R [v.4.0.3]122 and RStudio [v.1.3.1093]123 (see “Methods” section); specimens visualized in Dragonfly [v.4.1]114.
