Fig. 3

Matsuoka–Okada cycles and diversification in Gephyrocapsa. a Size variation of coccoliths in Gephyrocapsa spp. in the last 1.8 Ma at site 709^17,39, with three coccolith size enlargement events (MO1–MO3) associated with fossil species. Shades of green colour correspond to the relative density of coccolith. A phylogenetic chronogram of extant Gephyrocapsa based on relaxed molecular clock and calibrated with the first appearance of G. huxleyi (node 2) in the fossil record. Branches of the tree are scaled to coccolith length, estimated by ancestral trait reconstruction (Supplementary Fig. 9), and shown for each node. Mean coccolith length (in μm) for modern and ancestral species is shown in white rectangle at each tip and node. b Coccolith traits measured. c Global Δ sea surface temperature (ΔSST) over 1800 ka⁵². Blue line is for mean variations, red and blue bands for 95% confidence intervals (respectively, variability and jackknife). Red line corresponds to loess smoothing and its associated grey band to 95% confidence interval. White arrows correspond to stepwise changes in relative global SST