Fig. 2

Fig. 2

aD. rerio fish at stage PR, iridophores (arrowhead) emerge along the horizontal myoseptum (asterisk) to form the first light stripe. bD aesculapii fish at stage PR. cD. rerio at stage SP, the first light stripe is flanked dorsally and ventrally by emerging dark stripes. dD. aesculapii at stage SP, iridophores emerge in a scattered fashion. eD. rerio at stage J++, light stripes are covered by compact xanthophores. fD. aesculapii at stage J++, melanophores and xanthophores broadly intermix. gD. rerio at stage JA, the stripes are fully formed. hD. aesculapii at stage JA, melanophores and xanthophores sort out loosely into vertical bars of low contrast; no dense iridophores are visible between the dark bars. a–d Incident light illumination to highlight iridophores, e–h bright field illumination to visualise xanthophores and melanophores. All pictures are representative for the corresponding species and stages (n ≥ 3). Staging of animals according to Parichy et al.⁸³. PB (pectoral fin bud, 7.2 mm SL). SP (squamation posterior, 9.5 mm SL). J++ (juvenile posterior, 16 mm SL). JA (juvenile-adult, >16 mm SL). Scale bars correspond to 250 μm.