Fig. 6. Primary role for metamorphic melanophores in adult pigment pattern formation across species. Shown are repeated images of the same region of the ventral flanks in representative individuals of D. nigrofasciatus, D. rerio, D. kyathit, D. kerri, D. albolineatus, D. choprae, and T. albonubes (compare with Fig. 1). Only selected images are shown from the complete series for each individual. Row 1, shortly after the onset of pigment pattern metamorphosis in each species. Row 8, terminal stages of pigment pattern metamorphosis when the adult pigment patterns have formed; row 8', schematics showing melanophores present at early larval stages (brown) and melanophores that differentiated during metamorphosis (black), as revealed by tracing individual melanophores throughout pigment pattern metamorphosis. Squares indicate the horizontal myoseptum; horizontal arrowheads indicate the ventral aspect of the myotome. In D. nigrofasciatus, numerous early larval melanophores relocate (arrowheads) from the early larval stripe along the ventral aspect of the myotome (horizontal arrowhead, row 1) to the adult ventral primary melanophore stripe on the flank (row 8,8'). In D. rerio and D. kyathit, early larval melanophores typically do not contribute to the compact stripes of the adult. In D. kerri, a more diffuse stripe pattern arises compared with in D. nigrofasciatus, D. rerio and D. kyathit; although a few early larval melanophores leave their initial positions (arrowheads, row 5), they typically do not enter into the adult stripes. In D. albolineatus, rare early larval melanophores leave the larval stripes (arrowhead, row 6) but do not contribute substantially to the uniformly dispersed anterior melanophores or weak melanophore stripes posteriorly. In D. choprae, a few early larval melanophores leave the larval stripes (arrowheads, row 7) but do not join the horizontal adult stripes that form during metamorphosis, or the vertical barring pattern that develops at later stages; the same early larval melanophore behaviors are seen in the vertically striped D. shanensis (I.K.Q. and D.M.P., unpublished). Finally, in T. albonubes, a few early larval melanophores (arrowheads, row 6) leave the larval stripes but do not move far onto the flank where diffuse horizontal adult stripes develop in the adult. In all panels, larvae were imaged at a 30° angle to better visualize the ventral-lateral margin of the flank and the early larval melanophores, and images are rescaled to show the same region of the flank. Slight differences in starting pigment patterns (row 1) principally reflect inter-individual variation and minor differences in developmental stage. nigrof, D. nigrofasciatus; alb, D. albolineatus; T. alb, T. albonubes. Number of larvae examined: D. nigrofasciatus, 10; D. rerio, 5; D. kyathit, 5; D. kerri, 2; D. albolineatus, 4; D. choprae, 2; T. tanichthys, 4. Overall contributions of embryonic neural crest-derived melanophores and metamorphic melanophores are similar in other regions of developing adult pigment patterns (data not shown).