Chromis pacifica, a new Pacific Ocean damselfish distinct from Indian Ocean Chromis agilis (Teleostei: Pomacentridae)

The common coral-reef damselfish, Chromis agilis Smith, 1960, has long been considered a widespread Indo-Pacific species, ranging from East Africa to French Polynesia and the Hawaiian Islands. The population from the western Indian Ocean looks different from the more well-known Pacific Ocean population and has been described separately as the species Chromis xutha Randall, 1988. However, Chromis agilis was described from type specimens from Seychelles and East Africa, and thus C. xutha is a junior synonym of Chromis agilis. The Pacific population widely recognized as C. agilis is therefore unnamed and is described here as the new species Chromis pacifica. It differs from true C. agilis by having a larger black spot at the base of the pectoral fin, lateral greyish to purplish stripes along scale rows, more dorsal-fin and pectoral-fin rays and lateral-line scales, and a larger size (up to 80 mm SL vs. 55 mm SL). An expanded diagnosis of C. agilis is presented, along with photographs illustrating the differences from C. pacifica