Two new species of Chromis (Teleostei: Pomacentridae) from northwestern Australia and the southwestern Pacific Ocean, previously part of C. fumea (Tanaka, 1917)
Gerald R. Allen & Mark G. Allen
The common coral-reef damselfish, Chromis fumea (Tanaka, 1917) was previously reported as widely distributed in the western Pacific Ocean and northwestern Australia, with disjunct populations in the northwestern Pacific, Western Australia, and the southwestern Pacific Ocean. The present investigation reveals the nominal species is composed of three distinct species, including two new species described herein, forming an anti-tropical species complex with Chromis nitida, from the Great Barrier Reef of Australia to southern New South Wales. The true C. fumea is mainly restricted to Japan and Taiwan, with vagrants ranging southward to Malaysia; it is characterized by a larger body size, a graded color pattern on the body, a small white spot at the base of the last dorsal-fin rays, and black upper and lower margins on the caudal fin. Chromis nitida is sharply bicolored with a black band from the eye to the tip of the soft dorsal fin and no posterior white spot. Chromis norfolkensis , n. sp. is described from 8 specimens, 47.5-83.3 mm SL, collected in the southwestern Pacific Ocean at Norfolk Island, northern New Zealand, and Chesterfield Bank, Coral Sea, with underwater photographic records from New South Wales and New Caledonia. It usually has more gill rakers than C. fumea, and the color pattern in life is diagnostic: adults are brownish above and whitish below, the transition relatively abrupt with a diagonal demarcation from the eye to a conspicuous small, rounded, white spot at the base of the last dorsal-fin rays; both the outer portion of the dorsal fin and the upper and lower margins of the caudal fin have prominent broad black bands with a bright blue-white edge. Chromis sahulensis, n. sp. is a smaller species, described from 86 specimens, 15.3-58.3 mm SL, from northwestern Australia. It has more gill rakers than C. fumea, and the color pattern is diagnostic: yellowish brown dorsally grading to paler grey-brown on the sides, with the white spot at the base of the last dorsal-fin rays more saddle-like and farther onto the upper caudal peduncle, and brownish bands along the upper and lower margins of the caudal fin. The mtDNA COI barcode sequence of C. sahulensis is 3.8% divergent from C. fumea from Taiwan and 5.15% from C. nitida from Queensland.
Allen, G.R. & Allen, M.G. (2021) Two new species of Chromis (Teleostei: Pomacentridae) from northwestern Australia and the southwestern Pacific Ocean, previously part of C. fumea (Tanaka, 1917). Journal of the Ocean Science Foundation, 38, 78-103.
publication date: 31 October 2021