Figure 4

Time-calibrated phylogeny of animals. Phylogeny of crown-Opisthokonta obtained by Philippe et al.¹⁸, time-calibrated using Calibration set A, an autocorrelated relaxed clock model, and 1000 Ma root age prior (see text). Gray areas indicate Sturtian (left) and Marinoan (right) glaciations²¹. Thick red branches highlight pre-Snowball Earth radiation of animal lineages. Bars at selected deep nodes represent 95% CrIs; above them density plots highlighting the frequency of different age estimates around the mean are shown (produced with custom python and R scripts developed by S. Vargas). Ages in million years before present (Ma). Stratigraphic abbreviations: Ordov., Ordovician; Sil., Silurian; Carbonif., Carboniferous; Pg., Palaeogene; Ng., Neogene. Taxon abbreviations: Hom., Homoscleromorpha; Cal., Calcarea; Hex., Hexactinellida; Dem., Demospongiae; Ant., Anthozoa; Med., Medusozoa; Deut., Deuterostomia; Prot., Protostomia; Ecd., Ecdysozoa; Loph., Lophotrochozoa.