C. paucifasciatus is one of the "crowned" butterflyfishes. These form a group of largely
allopatric species sharing the overall color pattern of dark forward-pointing
chevrons on silvery hues, (usually) a black-and-white crown spot and yellow to red hindparts to a stunning degree; they differ in the exact combination of hues and some small pattern details. Other members of this lineage are the closely related
Seychelles (
C. madagaskariensis) and
Atoll butterflyfishes (
C. mertensii), and the more distant
pearlscale butterflyfish (
C. xanthurus). The "crowned"
Chaetodon are a clearly recognizable
clade, but their further relationships are otherwise less clear. They were often placed in the
subgenus Exornator, or considered a distinct subgenus
Rhombochaetodon. According to various
DNA sequence studies, some older and more singular lineages. These include species such as the
Asian butterflyfish (
C. argentatus), the
blue-striped butterflyfish (
C. fremblii) and
Burgess' butterflyfish (
C. burgessi).
C. burgessi is in fact so peculiar that it was placed in a
monotypic subgenus
Roaops. But recognition of this would probably result in several other small or monotypic subgenera becoming justified, and the older
Rhombochaetodon would be the more conveniently apply to the entire
radiation. But the expanded group is of unclear relationships to species like the
speckled butterflyfish (
C. citrinellus) and the
four-spotted butterflyfish (
C. quadrimaculatus). These might be members of the subgenus
Exornator – the lineages around the
spot-banded butterflyfish (
C. punctatofasciatus) – and
C. citrinellus certainly looks somewhat similar to these. Yet
phylogenetically, their position towards
Rhombochaetodon is unresolved, and ultimately it might be better to merge both
Rhombochaetodon and
Roaops in
Exornator. If the genus
Chaetodon is split up,
Exornator might become a subgenus of
Lepidochaetodon or a separate genus. ==References==