Fig. 4

Phylomorphospace of the genus Codium (n = 72), with placement of Protocodium sinense. Larger circles are selected representative species. Color coding reflects K-means clustering for seven groups. Black diamond points to the root of the tree; Pie charts represent significant loadings (see Methods and Additional file 1), with acronyms taken from Verbruggen et al. [23]: EM-BCP, branch compression; EM-BCS, branch constriction; EM-BS, branch shape; EM-BT, branching type; EM-HAB, thallus habit; EM-HF, holdfast type; EM-SU, thallus surface; UH-SC, utricle hairs, presence of scars or hairs; UH-SD, utricle hairs, density; UM-CP, utricle composition. Diagrams represent the major subdivisions of the first two dimensions: thallus shape on axis 1 (left to right: mat-forming, spherical, erect/repent; 61% total variance explained) and presence (upper half)/absence (lower half) of hairs or scars on axis 2 (21% total variance explained)