Phylogenetic tree and estimated divergence times.

<p>A maximum-likelihood phylogenetic tree was inferred from concatenated protein sequences corresponding to 52 shared single-copy genes. Species divergence was estimated using a Bayesian relaxed molecular clock model. Divergence time is given in million years; 95% confidence intervals are shown in brackets. The divergence time between <i>S</i>. <i>bovis</i> and <i>S</i>. <i>haematobium</i> was estimated to be 1.85 million years (95% confidence interval 1.21–2.63 mya). The model was calibrated using previously published divergence times and ages of fossil records of intermediate snail hosts.</p>