Four-spotted Butterflyfish or fourspot butterflyfish (Chaetodon quadrimaculatus)

Fourspot butterflyfish

The Four-spotted Butterflyfish or fourspot butterflyfish (Chaetodon quadrimaculatus) is a species of butterflyfish (family Chaetodontidae) found in the Pacific Ocean from the Ryukyus, Ogasawara (Bonin) Islands and Taiwan to the Hawaiian, Marquesan, and Pitcairn islands, south to the Samoan and Austral Islands and the Marianas and Marshall Islands in Micronesia.

Fourspot butterflyfish

image source: http://en.wikipedia.org/wiki/User:Aquaimages

It is a quite distinct species, but most closely related to the Speckled Butterflyfish (C. citrinellus). Together they are basal in the subgenus Exornator, and might be intermediate between the core group of this subgenus and the species of the Rhombochaetodon (or Roaops) lineage. If that is correct, the latter would require to be merged into Exornator. If the genus Chaetodon is split up, Exornator might become a subgenus of Lepidochaetodon.