Fig. 2.—

Simplified best obtained ML tree of the full metazoan opsin gene data set and the placement of the five opsin genes from the tardigrade Hypsibius dujardini (highlighted in red). See supplementary figure S1, Supplementary Material online, for the uncondensed tree. (A) Detail view of the bilaterian r-opsin clade, in which Hd-r-opsin of H. dujardini occurs as the sister group to the onychophoran onychopsin clade. (B) Detail view of the neuropsin/opsin-5 subgroup of Group 4 opsins, illustrating the placement of Hd-neuropsin of H. dujardini among the neuropsins from other protostomes. (C) Detail view of the bilaterian c-opsin clade, in which Hd-c-opsin1, Hd-c-opsin2 and Hd-c-opsin3 of H. dujardini are nested as a monophyletic group within the panarthropod c-opsin clade containing the arthropod pteropsins.