Phylogeny of Scaptomyza and the orthologs of the odorant receptor Or67b (A) Time-calibrated Bayesian chronogram of Scaptomyza and Drosophila spp. inferred from nine protein coding and two ribosomal genes. Bars indicate 95% highest posterior density (HPD) age estimates in millions of years ago (Ma). Tree topology labeled as follows: Posterior Probability (PP):ML BS: Parsimony BS on branches. Scale bar proportional to Ma. (B) ML phylogeny reconstructed based on the coding sequence of Or67b orthologs from 12 Drosophila species, S. pallida, S. hsui, S. graminum, and S. flava. Source species for the Or67b coding sequences crossed into the empty neuron systems in subsequent figures are indicated. Support values are only indicated for bifurcations with less than 100% support in any analysis, labeled as in (A). Branches with significant support (FDR P-value < 0.05) for d_N/d_S values different from the background rate are indicated with colored branch labels (blue where the foreground rate is less than the background, and red/enlarged fonts where d_N/d_S is greater than the background). Only S. flava and D. mojavensis branches have significantly elevated d_N/d_S according to branch model tests. Scaptomyza flava, S. pallida, and D. melanogaster labeled identically to (A). Scale bar units are substitutions per site.