Fig. 5
From: Ancient coexistence of norepinephrine, tyramine, and octopamine signaling in bilaterians
Evolution of adrenergic, octopamine, and tyramine signaling in bilaterians. a Phylogenetic tree of major clades of bilaterian animals with the presence/loss of specific G-protein-coupled receptor (GPCR) families indicated. b Phyletic distribution of adrenergic, octopamine, and tyramine GPCR families across major bilaterian clades. Half squares mean losses in a large number of species in a phylum