Chromis tweddlei, a new deep‐water species of damselfish (Pomacentridae) from the Cargados Carajos Bank, southwestern Indian Ocean

Abstract Chromis tweddlei , a new species of damselfish, is described from seven specimens, 88.8–111.1 mm standard length (SL), collected during a 2008 expedition by the R.V. Dr. Fridtjof Nansen at 214–219 m depth (an unusually deep occurrence for the genus) on the Cargados Carajos Bank, Mascarene Plateau, southwestern Indian Ocean. Chromis tweddlei sp. nov. closely resembles Chromis axillaris , Chromis pelloura , and Chromis woodsi , the only congeners occurring in the western Indian Ocean (WIO) that share the character of having 14 dorsal‐fin spines and a dark caudal band. Chromis tweddlei sp. nov. can be distinguished from its regional congeners by having II,13–14 anal‐fin rays, 19–20 pectoral‐fin rays, 18–19 tubed lateral‐line scales, 4 scales above lateral line to the origin of dorsal fin, 29–32 total gill rakers, and colouration, including a caudal band that tapers anteriorly the full length of the caudal peduncle. A key to the 14 dorsal‐fin spine species of Chromis from the WIO is provided.