Chrysiptera caesifrons, a new species of damselfish (Pomacentridae) from the south-western Pacific Ocean

Chrysiptera caesifrons is described on the basis of 23 type specimens, 23.3–48.5 mm SL, from the Raja Ampat Islands (West Papua Province), Indonesia, and 184 additional non-types, 17.8–60.7 mm SL, from Papua New Guinea, Vanuatu, New Caledonia, and the Great Barrier Reef of Australia. Additional records based on photographic evidence and underwater observations include Halmahera and the Solomon Islands. The new species is closely allied to C. rex from the Ryukyu Islands, Taiwan, Palau, eastern Indonesia (eastern Kalimantan and Java eastward), Timor Leste, Raja Ampat Islands (off western extremity of New Guinea), and offshore reefs of Western Australia, as well as to C. chrysocephala from the South China Sea region and Sulawesi. Although the new species was previously confused with C. rex, it is clearly separable from both sibling species on the basis of colour pattern and from C. rex by a 6.4% difference (average pairwise distance) in the mitochondrial control region DNA sequence and from C. chrysocephala by a 4.3% difference (K2P minimum interspecific distance) in the barcode COI mtDNA sequence.