Figure 1.

Mean body lengths for extant mysticetes and estimated length for fossil species (baleen-bearing mysticetes, circles; toothed mysticetes, triangles) are plotted according to their age as inferred from our phylogeny. Shaded areas correspond to 80 (white), 90 (grey) and 95% (black) quantiles of 1000 Brownian motion simulations on mysticete phylogeny and illustrate that the modern fauna is both lacking in small species (less than 5 m) and over-represented in large ones (more than 10 m), relative to the fossil record. To the right is a smooth-spline fitted to the Eocene–Present oxygen isotope curve [36], and used as a proxy in modelling temperature-dependent body size evolution. Higher δ¹⁸O values correspond to cooler temperatures.