a, Maximum likelihood reconstructions of the evolution of genome size in jawed vertebrates. Genome size evolution used a new Bayesian time-calibrated phylogeny and genome size values obtained from assembled genomes or the Genome Size Database (http://www.genomesize.com/search.php). b, Maximum likelihood reconstruction of cell size evolution in lungfish. Cell size reconstruction used the tip-dated phylogeny of ref. 13, including extinct lungfishes and cell size data from ref. 13. Branch lengths are in million years and colours denote genome size (in Gb) or cell volume (μl3). Major geological periods are highlighted with colours. Dev, Devonian; Car, Carboniferous; Per, Permian; Tri, Triassic; Jur, Jurassic; Cre, Cretaceous; Pal, Paleogene; NQ, Neogene–Quaternary.