Initially described in 1882, Chromis enchrysurus, the Yellowtail Reeffish, was redescribed in 1982 to account for an observed color morph that possesses a white tail instead of a yellow one, but morphological and geographic boundaries between the two color morphs were not well understood. Taking advantage of newly collected material from submersible studies of deep reefs and photographs from rebreather dives, we sought to determine whether the white-tailed Chromis is actually a color morph of Chromis enchrysurus or a distinct species. These alignments for mitochondrial genes cytochrome b and cytochrome c oxidase subunit I  were used to generate phylogenetic trees that separated Chromis enchrysurus and the white-tailed Chromis into two reciprocally monophyletic clades. Genetic, morphological, and biogeographic data all indicate that the white-tailed Chromis is a distinct species, herein described as Chromis vanbebberae sp. nov. The discovery of a new species within a conspicuous group such as damselfishes in a well-studied region of the world highlights the importance of deep-reef exploration in documenting undiscovered biodiversity.

Sequence data for Chromis enchrysurus and Chromis vanbebberae were collected via DNA extraction and sanger sequencing. Sequences for other pomacentrid species were imported from GenBank. Sequences were aligned in Geneious version 10.2.6.