A new species of damselfish (Chromis: Pomacentridae) from Papua New Guinea.

A new species of pomacentrid fish, Chromis howsoni, is described from 24 specimens, 30.7–56.2 mm SL, collected in 17–20 m at Milne Bay and Oro Provinces, Papua New Guinea. Diagnostic features include usual counts of XII,12 dorsal rays; II,12 anal rays; 15–16 pectoral rays; 2 spiniform caudal rays; 13 tubed lateral-line scales; body depth 1.6–1.8 (usually 1.7) in SL. The new taxon is closely allied to Chromis amboinensis, differing mainly on the basis of colour pattern and a slightly shorter caudal peduncle (length 2.3–2.9 versus 1.8–2.3 in head length). It is distinguished by an overall yellowish brown colour, yellow pelvic fins, and yellow areas posteriorly on the dorsal and anal fins. In contrast, C. amboinensis is overall brownish grey with white pelvic fins, and whitish or translucent areas posteriorly on the dorsal and anal fins. The two species occur sympatrically in Papua New Guinea, but exhibit marked habitat partitioning, with C. howsoni the only species present in sheltered coastal inlets and C. amboinensis vastly outnumbering C. howsoni on outer exposed reefs