Fig. 2.

Evolution and adaptive landscape of relative eye socket size in early tetrapods summarizing our phylogenetic comparative study performed over a sample of 1,000 time-calibrated trees. The circles (red for finned, yellow for finned transitional, blue for digited, and brown for digited aquatic tetrapods) represent body size-corrected relative eye socket sizes, the residuals from phylogenetically generalized least squares regression (PGLS) of log₁₀-transformed variables (Materials and Methods and SI Appendix, Scaling of Orbit and Skull Length in Early Tetrapods). The thick branches indicate positions of well-supported selective regime shifts, with associated factors signifying the change in eye socket size compared with the ancestral regime (before the green dot) after body size effects are accounted for.