Volume 26, Issue 23, Pages R1224-R1225 (December 2016) Fish ‘tails’ result from outgrowth and reduction of two separate ancestral tails  Lauren Sallan  Current Biology  Volume 26, Issue 23, Pages R1224-R1225 (December 2016) DOI: 10.1016/j.cub.2016.10.036 Copyright © 2016 Elsevier Ltd Terms and Conditions

Figure 1 Ray-finned fish phylogeny and caudal ontogeny. Caudal fins are shown in blue, whereas tail and associated fin/dermal structures are red. (A) Phylogeny of ray-finned fishes (Actinopterygii) showing adult caudal morphologies for terminal genera. Taxonomic abbreviations: Cl = Cladistia, Ch = Chondrostei, Ho = Holostei. (B) Ontogenetic stages of caudal structures in the extant pike Esox, based on [1]. Scale bar = 1 mm. (C) Aetheretmon juvenile and adult caudal ontogeny. From left to right: P13167 (3 cm total length); P61006 (4 cm total length); P13161 (6 cm total length); P60984 (8 cm total length). See Table S1. White scale bars = 5 mm. (D) Monotrete pufferfish caudal ontogeny. Black scale bars = 0.5 mm. (E) Early-stage Polypterus (Cladistia). (F) Early-stage Polyodon (Chondrostei). (G) Early-stage Lepisosteus (Holostei). (H) Early-stage Amia (Holostei). Growth series for E–H presented in Figure S1. See Supplementary experimental procedures for sources. Morphological abbreviations: al, axial lobe; cf, caudal fin; dr, dorsal ridge scales; ec, epichordal lobe; fr, fringing fulcra; ha, hemal arch; no, notochord; pe, peduncle; sc, scales; tf, tail fin. Current Biology 2016 26, R1224-R1225DOI: (10.1016/j.cub.2016.10.036) Copyright © 2016 Elsevier Ltd Terms and Conditions