Distances and evolutionary rates for chondrichthyan and tetrapod representatives.

Distances (number of substitutions per site) were calculated by codeml for different pairs of species using Callorhinchus milii (Cm) as outgroup. Applying divergence times estimated in this study (306 Ma) as well as previous studies (203 Ma, 312 Ma and 330 Ma), evolutionary rates were calculated for three chondrichthyans and four tetrapod species. Abbreviations: aa, amino acid; Ma, million years ago; Hf, Heterodontus francisci; Sc, Scyliorhinus canicula; Le, Leucoraja erinacea; Gg, Gallus gallus; Hs, Homo sapiens; Ac, Anolis carolinensis; Xt, Xenopus tropicalis; O, Last common ancestor of the two selected species.