Five species of damselfishes of the genus Chromis, all collected from deep (more than 60 m) coral reef habitats in the western Pacific, are among the first new fish species to be described in 2008.
The descriptions of Chromis abyssus, C. brevirostris, C. circumaurea, C. degruyi and C. earina by Richard Pyle, John Earle and Brian Greene are published in a recent issue of the journal Zootaxa.
Chromis abyssusGiven the common name of Deep Blue Chromis, this species can be distinguished from congeners in having a combination of the following characters: orsal rays XIV,12"13 (usually 13); anal rays II,12"14 (usually 13); pectoral rays 18"19 (usually 19); spiniform caudal rays 3; tubed lateral-line scales 14"16; gill rakers 6"7+17"18 (usually 7+18; total 24"25, usually 25); body depth 1.58"1.83 in SL; color when fresh dark gray with a large iridescent dark blue spot at center of each scale; membranes on median fins and pelvic fins opaque charcoal gray, with an iridescent dark blue margin on the spinous portion of the dorsal and anal fins; caudal fin mottled iridescent dark blue and black; pectoral fins with a black ovoid spot covering the basal portion and pectoral-fin axil.
This species is only known from the Agulpelu Reef in Palau, and is named in honour of the BBC documentary Pacific Abyss, which funded the expedition from which the type material was collected.
Chromis brevirostris
Chromis brevirostris image kindly supplied by John Earle.
Also known as the Shortsnout Chromis, this species differs from congeners in having a relatively short snout and the following characters: orsal rays XIII,13"14 (usually 14); anal rays II,15"16; pectoral rays 18"19 (usually 19); spiniform caudal rays 2"3 (usually 3); tubed lateral-line scales 14"16; gill rakers 6"8+19"22 (usually 6"7+19"21; total 26"29); body depth 1.57"1.77 in SL; color when fresh pale lavender-tinged gray dorsally, paler ventrally; three or four rows of scales dorsally from nape to upper caudal peduncle with gold edges; small scales on basal sheath of dorsal fin almost entirely gold; median fin membranes lavender gray or translucent blue, suffused with gold color; iris yellow. Chromis brevirostris is named after its short snout (Latin brevis = short and rostris = nose or snout), and is known from the Marshall Islands southward to Fiji, across the Caroline Islands from Puluwat to Palau, and south to Vanuatu.
Chromis circumaurea
Chromis circumaurea image kindly supplied by John Earle.
The authors give this species the common name of Gold-rim Chromis.
It can be distinguished from congeners in having a combination of: orsal rays XIV,12"13 (usually 13); anal rays II, 13"14 (usually 13); pectoral rays 18"19; spiniform caudal rays 3; tubed lateral-line scales 16"17; gill rakers 6"7+20"21 (total 26"27); body depth 1.68"1.86 in SL; color when fresh mahogany brown with bright yellow distally on spinous portion of dorsal fin; soft portion of dorsal fin, caudal fin, and anal fin bright yellow.
This species is known from the Marshall and Mariana Islands and is named after its distinctive colour pattern of a golden-yellow anal fin, caudal fin, and outer margin of the dorsal fin (from the Latin circum, meaning around and aurea, meaning gold).
Chromis degruyi
Chromis degruyi image kindly supplied by John Earle.
Given the common name of DeGruy's Chromis (this species is named after Michael DeGruy, who attempted to catch the first adult specimen of this species), this species differs from congeners in having the following characters: orsal rays XIII"XIV,11"12 (usually XIV,12); anal rays II,11"12 (usually 12); pectoral rays 18; spiniform caudal rays 3; tubed lateral-line scales 15"17; gill rakers 7+20"21 (total 27"28); body depth 1.84"1.99 in SL; color of adults when fresh dull brownish yellow with nine thin lavender-gray stripes on side of body, with a prominent black spot on dorsal half of pectoral-fin base. This species is found throughout the Caroline Islands.
Chromis earina
Chromis earina image kindly supplied by John Earle.
Also known as the Spring Chromis, this species is distinguished from congeners in having a combination of: orsal rays XII"XIII,11"12 (usually XIII, 12); anal rays II,12; pectoral rays 17"18 (usually 18); spiniform caudal rays 3; tubed lateral-line scales 13"15 (rarely 16); gill rakers 6"8+18"21 (total 26"28, rarely 25); body depth 1.65"1.9 in SL; color when fresh pale slate blue (bright pale green in life); a white spot (sometimes two white spots) roughly the size of a scale mid-laterally on the body; malachite green area above orbit and in inter-orbital space and nape; dorsal and anal fins with bright distal border of pale turquoise blue.
This species is named for its distinctive green colour (from the Greek earinos, meaning the colour of spring) and is found from Puluwat westward to Palau, south to Papua New Guinea, Vanuatu and Fiji.
For more information, see the paper: Pyle, RL, JL Earle and BD Greene (2008) Five new species of the damselfish genus Chromis (Perciformes: Labroidei: Pomacentridae) from deep coral reefs in the tropical western Pacific. Zootaxa 1671, pp. 3"31.
urn:lsid:zoobank.org:pub:68376390-7809-46FF-9EC4-1371B4AAD0FF
Images kindly supplied by Richard Pyle and John Earle.