(A) Maximum likelihood (ML) phylogenetic analysis (RAxML, LG+Γ, Figure 6—source data 2) of opsin proteins based on the dataset of Vöcking et al. (2017) including the 10 Clytia opsins, rooted with GPCR families closely related to the opsin family. (B) Unrooted ML phylogenetic analysis of available medusozoan opsins (RAxML, LG+Γ, Figure 6—source data 3). In both trees, ML bootstrap support values (500 replicates) are shown as circles on the branch tips: black circles ≥95%, grey circles ≥70%, white circle ≥50%. Bayesian analyses (MrBayes, LG+Γ) reconstructed trees with similar topologies; Bayesian posterior probabilities greater than 0.70 (A) or 0.95 (B) are shown next to the branches (A) or on the nodes (B). The orange dot highlights CheOpsin9. NCBI or Uniprot reference numbers and Clytia opsin names are shown. In (A), c-opsins = ciliary opsins; tetraopsins = retinal G protein-coupled receptor, Neuropsin and Go-opsin as defined by Ramirez et al., 2016; r-opsins = rhabdomeric opsins; ctenopsins = ctenophore opsins; chaopsin = as defined by Ramirez et al., 2016. In (B), a red star indicates expression in the gonad. Scale bars: estimated number of substitution per site.