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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(I.K.Q. and D.M.P., unpublished).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).
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