Chromis earina, Pyle, R. L., Earle, J. L. & Greene, B. D., 2008

Pyle, R. L., Earle, J. L. & Greene, B. D., 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 : 21-25

Chromis earina , new species

urn:lsid:zoobank.org:act:269D61C2-50B3-4A8C-BEFB-D9CFBCF91BA4

Spring Chromis

(Figs. 5a -5c; Tables 3 & 6; Morphbank137; GenBank138; Barcode139)

Holotype. MNHN 2007-1921140 (63.3 mm SL), Vanuatu; Espiritu Santo; off W coast of Tutuba Island (15°32'39.28"S, 167°16'29.82"E): near large boulder along steep slope with rubble and sand; many gorgonians, 116 m, rotenone and vacuum device, R.L. Pyle and B.D. Greene, 22 October 2006 [PCMB 3131141].

Paratypes. BMNH 2007.10.31.5142 (62.5 mm SL), Vanuatu; Espiritu Santo; off W coast of Tutuba Island (15°32'35.23"S, 167°16'49.65"E): large rock outcrop with surrounding sand and rubble, below base of large drop-off, 116 m, hand net, B.D. Greene, 20 October 2006. BPBM 37674143 (54.0 mm SL), Belau (Palau) Islands; Augulpelu Reef, W side (7°16'24.6"N, 134°31'26.4"E): shelf flanked by numerous small caves, 90 m, hand net, R.L. Pyle, 7 May 1997. BPBM 37714144 (4; 48.7-67.52), same locality as BPBM 37674: cave in drop-off, 90 m, rotenone, R.L. Pyle and J.L. Earle, 12 May 1997. BPBM 40720145 (2; 59.7-64.4 mm SL), Vanuatu; Espiritu Santo; off N end of Tutuba Island (15°32'28.57"S, 167°16'51.17"E): at base of outer reef dropoff ranging from 60-100 m, 100 m, rotenone and vacuum device, R.L. Pyle, 10 October 2006. CAS 225759146 (59.6 mm SL), Fiji Islands; Viti Levu Island; Suva; outside of Suva Harbor; S end of "Fish Patch"; below cave (18°9'36.6"S, 178°23'57.6"E): sand and rubble slope with scattered outcroppings, below base of vertical reef drop-off, 104-110 m, rotenone, R.L. Pyle, J.L. Earle, and J. Dituri, 4 February 2002. MNHN 2007-1926147 (35.7 mm SL), same collecting data as BPBM 40720. USNM 391140148 (66.3 mm SL), Vanuatu; Espiritu Santo; off W coast of Tutuba Island (15°32'58.78"S, 167°16'40.98"E): steep slope with rubble and sand, with some rocky outcrops with small caves and undercuts; many gorgonians, 100 m, rotenone and vacuum device, R.L. Pyle, 16 October 2006. WA M P. 32902-001149 (53.9 mm SL), Belau (Palau) Islands; Ngemlis Island, SE tip; "Big Drop" (7°6' 11.89"N, 134°15'2.67"E), 85 m, hand net, R.L. Pyle, 18 May 1997.

Diagnosis. Dorsal 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.

Description. Dorsal rays XIII,12 (one paratype with XII, another with 11); anal rays II,12; all dorsal and anal rays branched, the last to base in some specimens; pectoral rays 18 (17-18), the upper 2 and lowermost unbranched; pelvic rays I,5; principal caudal rays 8+7=15; upper and lower procurrent caudal rays 5, the anterior3 spiniform, the posterior 2 segmented and unbranched; tubed lateral-line scales 15 (13-16, one paratype with 16); posterior midlateral scales with a pore or deep pit 8 (4-8); scales above lateral line to origin of dorsal fin 3; scales below lateral line to origin of anal fin 9 (8-9); gill rakers 7+21=28 (6-8+18-21=26-28, one paratype with 25); surpaneural (predorsal) bones 3; vertebrae 12+13.

Body moderately deep, depth 1.90 (1.65-1.89) in SL, and compressed, the width 3.29 (2.71-3.70) in body depth; head length 2.96 (2.82-3.14) in SL; dorsal profile of head with convexity anterior to eye and concavity dorsal to eye; snout shorter than orbit diameter, its length 3.57 (3.52-4.40) in head length; orbit diameter 2.27 (2.11-2.40) in head length; interorbital space convex, its width 2.73 (2.60-3.22) in head length; caudal-peduncle depth 2.35 (2.00-2.43) in head; caudal-peduncle length 3.33 (2.79-4.26) in head.

Mouth terminal, small, oblique, the upper jaw forming an angle of about 52º to horizontal axis of head and body; posterior edge of maxilla reaching slightly beyond a vertical at anterior edge of pupil, the upper jaw length 3.06 (2.85-3.24) in head; teeth multi-serial, an outer row of conical teeth in each jaw, largest anteriorly; about 30 upper and about 27 lower teeth on each side of jaw; a narrow band of villiform teeth lingual to outer row, in 2-3 irregular rows anteriorly, narrowing to a single row on side of jaws; tongue triangular with rounded tip; gill rakers long and slender, the longest on lower limb near angle about four-fifths length of longest gill filaments; nostril with a fleshy rim, more elevated on posterior edge and located at level of middle of pupil, slightly less than one-third distance from front of snout to base of upper lip.

Opercle ending posteriorly in a flat spine, the tip relatively obtuse and obscured by a large scale; margin of preopercle smooth, the posterior margin extending dorsally to level of upper edge of pupil; suborbital with free lower margin extending nearly to a vertical at posterior edge of pupil.

Scales finely ctenoid; anterior lateral line ending beneath rear portion of spinous dorsal fin (between 12th and 13th dorsal-fin spines); head scaled except lips, tip of snout, and a narrow zone from orbit to edge of snout containing nostrils; a scaly sheath at base of dorsal and anal fins, about two-thirds pupil diameter at base of middle of spinous portion of dorsal fin, progressively narrower on soft portion; a column of scales on each membrane of dorsal fin, narrowing distally, those on spinous portion of dorsal progressively longer, reaching about two-thirds distance to spine tips on posterior membranes; scales on anal-fin membrane in two columns, progressively smaller distally; small scales on caudal fin extending to about one-half distance to posterior margin; small scales on basal one-fifth of pectoral fins; a median scaly process extending posteriorly from between base of pelvic fins, its length about one-third that of pelvic spine; axillary scale above base of pelvic spine slightly more than one-third length of spine.

Origin of dorsal fin over third lateral-line scale, the pre-dorsal distance 2.35 (2.24-2.48) in SL; base of spinous portion of dorsal fin contained 2.32 (2.13-2.52) in SL; base of soft portion of dorsal fin contained 6.28 (5.59-7.56) in SL; first dorsal spine 10.27 (9.20-11.88) in SL; second dorsal spine 7.11 (5.91-7.43) in SL; third dorsal spine 5.55 (4.88-6.01) in SL; fourth dorsal spine 5.62 (4.68-5.55) in SL; fifth dorsal spine 5.50 (4.68-5.51) in SL; sixth dorsal spine 5.57 (4.68-5.68) in SL; last dorsal spine 7.05 (6.17-7.21) in SL; membranes of spinous portion of dorsal fin moderately incised; fourth dorsal soft ray longest, its length 4.25 (3.61-4.74) in SL; first anal spine 10.85 (9.93-12.43) in SL; second anal spine 3.80 (3.76-4.23) in SL; first anal soft ray the longest, its length 4.32 (3.69-4.87) in SL; caudal fin forked, its length 2.83 (2.45-2.99) in SL, the caudal concavity 4.49 (3.33-5.26) in SL; fourth pectoral-fin ray longest, 2.82 (2.55-2.92) in SL; pelvic spine 5.23 (4.62-5.85) in SL; first soft ray of pelvic fin filamentous, usually reaching to first or second analfin ray (when not broken or otherwise damaged), its length 2.84 (2.47-3.91) in SL.

Color of adults and juveniles when fresh pale slate blue (bright pale green in life), slightly darker dorsally and slightly lighter on thorax; a white spot roughly the size of a scale mid-laterally, approximately below the tenth dorsal-fin spine and two scale rows below the lateral line, size and shape of spot variable, occasionally as two small spots in vertical orientation; malachite green area above orbit and in interorbital space, extending diffusely onto nape; bright band of pale turquoise blue below orbit extending across upper lip; spinous portion of dorsal fin color of body, with bright distal border of pale turquoise blue; soft dorsal-fin membrane pale blue, becoming translucent on distal half; caudal fin pale slate blue, becoming lighter and distally translucent on inner rays; caudal fin tips dark, almost black; anal fin pale slate blue, with pale turquoise blue anterior distal border; pectoral fin translucent; yellowish spot about scale size at upper pectoral axil; pelvic fin spine and first-ray filament pale turquoise blue, membranes translucent; iris dark gray with white inner border.

Color in alcohol olive-brown with whitish margins on median fins; white spot on side of body not visible.

Distribution. Collected or observed throughout the tropical western Pacific, from Puluwat westward to Palau, south to Papua New Guinea, Vanuatu and Fiji. It was not observed at Rarotonga (Cook Islands), Kiritimati(Line Islands), or American Samoa during brief surveys of deep reefs at those localities. A single specimen was also recently collected by Mark Erdmann (Conservation International) in 75 m depth at Misool Island, Raja Ampat Islands, Indonesia (G. Allen, pers. comm.).

Etymology. Named earina , a Latinized form of the Greek adjective earinos (meaning "the color of spring", i.e., green), in reference to the pale green color of this species in life.

Remarks. This species inhabits the same general habitat as the other new species described herein: steep outer reef slopes and drop-offs with rocky outcrops and small caves and holes, often in association with limestone talus. It is often observed in pairs or small groups, feeding low in the water column, and is generally abundant where it is found.

Similarities with other species are discussed in the Remarks section under the account of C. brevirostris .