Two new species of damselfishes (Pomacentridae) from Micronesia

Transcription

1 aqua, Journal of Ichthyology and Aquatic Biology Two new species of damselfishes (Pomacentridae) from Micronesia Gerald R. Allen 1 and John E. Randall 2 1) Department of Aquatic Zoology, Western Australian Museum, Francis Street, Perth, Western Australia 6000 and Conservation International, 1919 M. Street N.W. Suite 600, Washington, DC 20036, U.S.A. 2) Bishop Museum, 1525 Bernice Street, Honolulu, HI , U.S.A. Accepted: Keywords Taxonomy, marine fishes, Micronesia, Pomacentridae, Pomacentrus, new species Abstract Pomacentrus bipunctatus is described from 25 specimens, mm SL, collected at Enewetak Atoll in the Marshall Islands and Truk in the eastern Caroline Islands. Adults are similar in appearance to P. spilotoceps from Fiji, but the new species differs in having fewer pectoral fin rays (17 versus 18-19) as well as marked colour differences in juveniles and subadults. Most notably, the young stages of P. spilotoceps lack bright yellow coloration on the ventral portion of the body and adjacent fins. Pomacentrus yoshii is described on the basis of 10 specimens, mm SL, from Majuro Atoll in the southern Marshall Islands of Micronesia. It is distinguished from all Pacific members of the genus on the basis of its distinctive coloration, consisting of a blue anterior head, mainly yellowish body and fins, and large black spot covering the pectoral fin base. Pomacentrus pikei and P. sulfureus from the western Indian Ocean are similar in general apperance, but possess XIV rather than XIII dorsal fin spines. In addition, P. pikei has a much smaller spot on the pectoral fin base, which is restricted to the upper portion. On the basis of meristic features and general morphology, the new species appears to be closely related to P. philippinus from the eastern Indian Ocean and western Pacific, which differs significantly in overall colour pattern. Zusammenfassung Pomacentrus bipunctatus wird auf der Grundlage von 25 Exemplaren beschrieben, die mit einer Länge von 11,0 bis 61,9 mm (SL) beim Enewetak-Atoll an den Marshall-Inseln und bei Truk an den östlichen Karolinen gefangen wurden. Die erwachsenen Tiere ähneln im Erscheinungsbild P. spilotoceps von den Fidschis, doch besitzt die neue Art weniger Brustflossenstrahlen (17 im Vergleich zu 18-19) und andere Farbmuster bei den juvenilen und subadulten Tieren. Vor allem fehlt bei den jungen Stadien von P. spilotoceps die leuchtend gelbe Färbung im ventralen Bereich des Rumpfes und auf den angrenzenden Flossen. Weiterhin wird Pomacentrus yoshii auf der Grundlage von 10 Exemplaren mit 41,1-69,4 mm SL beschrieben, die vom Majuro-Atoll an den südlichen Marshall-Inseln stammen. Diese neue Art unterscheidet sich von allen anderen pazifischen Angehörigen der Gattung deutlich durch ihre Färbung: blauer vorderer Kopfbereich, überwiegend gelblicher Farbton auf dem Rumpf und den Flossen, ein großer schwarzer Fleck an der Basis der Brustflossen. Pomacentrus pikei und P. sulfureus vom westlichen Indischen Ozean sind im Erscheinungsbild ähnlich, besitzen aber XIV statt XIII Rückenflossenstrahlen. Außerdem ist bei P. pikei der Fleck an der Brustflossenbasis viel kleiner, er beschränkt sich auf den oberen Teil. Gemessen an den meristischen Daten und der allgemeinen Gestalt scheint die neue Art dem Riffbarsch P. philippinus vom östlichen Indischen Ozean und westlichen Pazifik nahe verwandt, der sich aber durch das gesamte Farbmuster deutlich unterscheidet. Résumé Pomacentrus bipunctatus est décrit d après 25 spécimens de 11,0 à 61,9 mm de LS, collectés près de l atoll Enewetak, dans les îles Marshall et Truk, à l est des Îles Caroline. Les adultes paraissent identiques au P. spilotoleps de Fiji, mais la nouvelle espèce se distingue par un nombre plus réduit de rayons aux pectorales (17 contre 18-19) ainsi que par des différences chromatiques marquées chez les juvéniles et les subadultes. Détail le plus frappant: dans sa jeunesse, le P. spilotoceps ne montre pas de jaune sur la partie ventrale du corps et sur les nageoires adjacentes. Pomacentrus yoshii est décrit d après 10 spécimens de 41,1 à 69,4 mm de LS de l atoll Majuro, au sud des îles Marshall en Micronésie. Il se distingue de tous les représentants pacifiques du genre par sa couleur particulière, c est-àdire, bleu sur l avant de la tête, corps et nageoires surtout jaunâtres, et une grande tache noire recouvrant la base de la pectorale. Pomacentrus pikei et P. sulfureus, de l ouest de l Océan Indien, se ressemblent quant à l aspect général, mais ont XIV plutôt que XIII 75

2 Two new species of damselfishes (Pomacentridae) from Micronesia rayons durs à la dorsale. En outre, P. pikei porte une tache nettement plus petite à la base de la pectorale, se réduisant à la partie supérieure. Sur base des données méristiques et de la morphologie générale, la nouvelle espèce semble très proche de P. philippinus, de l est de l Océan Indien et de l ouest du Pacifique, qui se distingue sensiblement par le patron de coloration général. Sommario Pomacentrus bipunctatus è descritto sulla base di 25 esemplari, mm SL, raccolti all Atollo Enewetak, Isole Marshall e a Truk nelle Isole Caroline orientali. Gli adulti sono simili nell aspetto generale a P. spilotoceps delle Fiji, ma la nuova specie differisce per avere un numero inferiore di raggi pettorali (17 versus 18-19) e una diversa colorazione nei giovani e nei subadulti. In modo particolare, gli stadi giovanili di P. spilotoceps mancano della brillante colorazione gialla sulla parte ventrale del corpo e sulle pinne adiacenti. Pomacentrus yoshii è descritto sulla base di 10 esemplari, mm SL, raccolti all Atollo Majuro nelle Isole Marshall meridionali della Micronesia. Si distingue da tutti gli altri membri del genere presenti nel Pacifico per la particolare colorazione, che consiste nella parte anteriore del capo blu, corpo e pinne principalmente giallastre e un ampia macchia nera che ricopre la base delle pettorali. Pomacentrus pikei e P. sulfureus dell Oceano Indiano occidentale sono simili nell aspetto generale, ma nella pinna dorsale posseggono XIV piuttosto che XIII spine. Inoltre, P. pikei ha una macchia molto più piccola alla base delle pettorali, che è ristretta nella porzione superiore. Per i dati meristici e la morfologia generale, la nuova specie appare strettamente imparentata con P. philippinus dell Oceano Indiano orientale e Pacifico occidentale, la quale, tuttavia, differisce in modo significativo per la colorazione complessiva. Introduction Damselfishes of the genus Pomacentrus are common inhabitants of coral reefs throughout the Indo-west and central Pacific Ocean. Allen (1991) recognized 54 species, but since then an additional 12 species have been described (Allen, 1992, 1993, 1995, 1999, 2002, 2004; Allen and Wright, 2003; Randall, 2002). The majority (66.6%) of species are primarily distributed in the western and central Pacific region, with lesser representation in the western and eastern Indian Ocean (21.2 and 10.9% respectively). Pomacentrus pavo (Bloch) is the only member of the genus that is widely distributed in the Indo-Pacific, from East Africa to the Tuamotu Islands. Most species have regionally limited distributions (e.g. northern Australia, Indonesia and Philippines, western Pacific rim, etc.), but a significant portion (9.4%) are restricted to relatively small areas such as eastern New Guinea, northern Madagascar, the Mascarene Islands, and Fiji-Tonga. The present paper describes two new species that are apparently restricted to eastern Micronesia. One of these was first collected at Truk and Enewetak by the second author in 1969 and the early 1970s, but was misidentified as Pomacentrus amboinensis Bleeker. The second species was also discovered by the second author, who collected a single specimen at Majuro Atoll in Realizing the species was undescribed, but lacking sufficient material, we eventually made a special request to Satoshi Yoshii, a Majuro-based aquarium fish collector, to obtain additional specimens. Finally, in December 2003, four specimens were collected by University of Hawaii graduate student Brian Greene with the help of Mr. Yoshii. Five additional specimens were procured by the second author during a brief visit to Majuro in May Methods Lengths of specimens are given as standard length (SL) measured from the anterior end of the upper lip to the base of the caudal fin (posterior edge of hypural plate); head length (HL) is measured from the same anterior point to the posterior edge of the opercle flap; body depth is the maximum depth taken vertically between the belly and base of the dorsal spines; body width is the maximum width just posterior to the gill opening; snout length is measured from the anterior end of the upper lip to the anterior edge of the eye; orbit diameter is the horizontal fleshy diameter, and interorbital width the least fleshy width; upper jaw length is taken from the front of the upper lip to the posterior end of the maxilla; caudal peduncle depth is the least depth, and caudal peduncle length is the horizontal distance between verticals at the rear base of the anal fin and the caudal fin base; lengths of fin spines and rays are measured to their extreme bases (i.e., not from the point where the ray or spine emerges from the basal scaly sheath); caudal fin length is the horizontal length from the posterior edge of the hypural plate to a vertical at the tip of the longest ray; caudal concavity is the horizontal distance between verticals at the tips of the shortest and longest rays; pectoral fin length is the length of the longest ray; pelvic fin length is measured from the base of the pelvic spine to the filamentous tip of the longest soft ray; pectoral ray counts include the small splint-like, uppermost rudimentary ray; only the tube-bearing anterior lateral line scales are counted; a separate count is given for the deeply-pitted scales occurring in a continuous series midlaterally on the caudal peduncle; the decimal figure.5 appearing in the scale row count above and below the lateral line refers to a small truncated scale at the respective bases of the dorsal and anal fins; gill raker counts include all rudiments and are presented as separate counts for the upper and lower limbs as well as a combined count; the last fin ray element of the dorsal and anal fins is usually branched near the base and is counted as a single ray. 76

3 Gerald R. Allen and John E. Randall Counts and proportions appearing in parentheses apply to the range for the paratypes if different from the holotype. A summary of fin ray, tubed lateral line scale, and gill raker counts is given in Table I. Proportional measurements expressed as percentage of the standard length are provided in Tables 2 and 3. Type specimens are deposited at the Bernice P. Bishop Museum, Honolulu (BPBM), California Academy of Sciences, San Francisco (CAS), Muséum National d Histoire Naturelle, Paris (MNHN), United States National Museum of Natural History, Washington, D.C. (USNM), and the Western Australian Museum, Perth (WAM). Pomacentrus bipunctatus n. sp. Figs. 1-4; Table I and II Holotype: BPBM 39300, 45.6 mm SL, Truk Lagoon (7 15 N, E), Caroline Islands: wreck of Japanese tanker, north of Fefan Island, 5-6 m, spear and quinaldine, J. E. Randall, 8 July Paratypes: BPBM 17967, 2 specimens, mm SL, Enewetak Atoll (11 30 N, E), Marshall Islands: isolated patch reef in lagoon off northern end of Enewetak Island, 17 m, spear and quinaldine, J. E. Randall and R. F. Meyers, 16 December 1974; BPBM 29259, 6 specimens, mm SL, Enewetak Atoll, Marshall Islands: Tunnel Pinnacle Reef in lagoon north-east of main channel, m, rotenone, J. E. Randall, P. L. Colin, and L. Bell, 26 August 1983; BPBM 28006, 7 specimens, mm SL, Enewetak Atoll, Marshall Islands: lagoon off Runit (Yvonne) Island, P. L. Colin, 19 February 1981; CAS , 3 specimens, mm SL, Enewetak Atoll, Marshall Islands: patch reefs in lagoon off Medren (Elmer) Island, 6-10 m, spear, P. L. Colin 29 March, 1981; MNHN , 45.4 mm SL, same data as holotype except collected on 7 July 1969; USNM , 2 specimens, mm SL, Enewetak Atoll, Marshall Islands: lagoon off Enewetak Island near Mid- Pacific Reasearch Laboratory, 21 m, rotenone, J. E. Randall, P. L. Colin, L. Bell, and S. Johnson, September 1982; WAM P , 3 specimens, mm SL, same data as holotype except collected on 7 July Diagnosis Dorsal rays XIII,14-15; anal rays II,14-16; pectoral rays 17; tubed lateral line scales 16-18; gill rakers 6-8 Fig. 1. Pomacentrus bipunctatus, holotype, mm SL, Truk, Caroline Islands. Photo by J. E. Randall. 77

4 Two new species of damselfishes (Pomacentridae) from Micronesia Fig. 2. Pomacentrus bipunctatus, underwater photograph of adult, approximately 70 mm total length, Enewetak Atoll, Marshall Islands. Photo by J. E. Randall. Fig. 3. Pomacentrus bipunctatus, underwater photograph of juvenile, approximately 40 mm total length, Majuro Atoll, Marshall Islands. Photo by J. E. Randall. 78

5 Table I. Meristic data for new species of Pomacentrus. Gerald R. Allen and John E. Randall Dorsal soft rays Anal soft rays Pectoral rays P. bipunctatus P. yoshii Tubed lateral line scales Upper limb gill rakers P. bipunctatus P. yoshii Lower limb gill rakers Total gill rakers P. bipunctatus P. yoshii (total 22-25); body depth in SL; colour in life generally brown, with darker scale margins forming transverse lines on body; about 10 large, pinkish to magenta spots scattered on operculum, also a prominent bluish black round spot (about onethird to half size of pupil) on upper margin of operculum, immediately anterior and slightly below lateral line origin; juveniles and subadults blue-grey to brownish with purplish hue and bright yellow lips, side of snout, abdomen, and pectoral region; juveniles also possess prominent ocellus on soft dorsal fin that persists until about 45 mm SL. Description Dorsal rays XIII,14 (XIII,14-15); anal rays II,14 (II,14-16); all dorsal and anal soft rays branched, the last to base; pectoral rays 17, the upper and lowermost pairs unbranched; pelvic rays I,5; principal caudal rays 15, the median 13 branched; upper and lower procurrent caudal rays 5, the posterior pair segmented; scales in longitudinal series 27-28; tubed lateral line scales 17 (16-18); posterior midlateral scales with a pore or deep pit (in continuous series) 8 (5-8); scales above lateral line to origin of dorsal fin 3; scales above lateral line to base of middle dorsal spine 1.5; scales below lateral line to origin of anal fin 8.5; gill rakers ( ), total rakers 23 (22-25). Body ovate, the depth 2.03 ( ) in SL, and compressed, the width 3.01 ( ) in body depth; HL 3.15 ( ) in SL; dorsal profile of head evenly-rounded from dorsal fin origin to snout; snout shorter than orbit, its length 3.30 ( ) in HL; orbit diameter 2.51 ( ) in HL; interorbital space convex, its width 4.01 ( ) in HL; caudal peduncle depth 2.25 ( ) in HL; caudal peduncle length 2.80 ( ) in HL. Mouth terminal, small, and oblique, forming an angle of about 36 to horizontal axis of head and body; maxilla reaching a vertical about even with anterior edge of orbit, the upper jaw length 3.40 ( ) in HL; teeth of jaws uniserial posteriorly, becoming biserial at front of jaws with addition of slender buttress teeth in spaces between main row of larger teeth; teeth incisiform to conical in shape, about in each jaw of holotype (excluding buttress teeth). Tongue triangular with rounded tip, set far back in mouth. Gill rakers long and slender, the longest on lower limb near angle about three-fourths length of longest gill filaments. Nostril round with slightly raised rim, level with lower edge of pupil and about midway between anterior edge of eye and upper lip. Opercle ending posteriorly in a flat spine, the tip obtuse, barely projecting from beneath a large scale; margin of preopercle with 12 serrae on left side of holotype (12-22 in paratypes > 45 mm SL, the number generally increasing with growth); preorbital with a single serra separated by a notch from suborbital series; lower edge of suborbital with 4 (5-12) serrae. Scales finely ctenoid; head scaled except lips, tip of snout, preorbital, and suborbital; a scaly sheath at base of dorsal and anal fins, averaging about one-half pupil width at base of dorsal fin and about the same width at base of anterior part of anal fin and gradually tapering in width posteriorly; a column of scales on each membrane of dorsal and anal fins, narrowing distally, those on spinous portion of dorsal fin progressively longer, reaching at least two-thirds distance to spine tips on posterior membranes, slightly farther on anterior soft rays, then gradually shorter on posterior part of fin; small scales on caudal fin extending about two-thirds distance to posterior margin; small scales on basal one-fifth of pectoral fins; a cluster of several scales forming median process, extending posteriorly from between base of pelvic fins, its length less than half that of pelvic spine; axillary scale above base of pelvic spine about one-third length of pelvic fin. 79

6 Two new species of damselfishes (Pomacentridae) from Micronesia Table II. Proportional measurements of selected type specimens of Pomacentrus bipunctatus as percentage of the standard length. Holotype Paratype Paratype Paratype Paratype Paratype BPBM BPBM WAM WAM USNM BPBM P P Standard length (mm) Body depth Body width Head length Snout length Orbit diameter Interorbital width Upper jaw length Caudal peduncle depth Caudal peduncle length Predorsal length Preanal length Prepelvic length Length dorsal fin base Length anal fin base Length pectoral fin Length pelvic fin Length pelvic fin spine Length first dorsal spine Length sixth dorsal spine Length last dorsal spine Length longest dorsal ray Length first anal spine Length second anal spine Length longest anal ray Length caudal fin Caudal concavity Origin of dorsal fin over second tubed lateral line scale, the predorsal distance 2.59 ( ) in SL; base of soft portion of dorsal fin contained about 2.1 times in base of spinous portion; dorsal fin spines gradually increasing in length to last spine; first dorsal spine 3.95 ( ) in HL; sixth dorsal spine 1.99 ( ) in HL; last dorsal spine 1.84 ( ) in HL; membranes of spinous portion of dorsal fin incised near spine tips; eighth dorsal soft ray longest, 1.50 ( ) in SL; first anal spine 4.09 ( ) in HL; second anal spine 1.80 ( ) in HL; longest (tenth) anal soft ray 1.28 ( ) in HL; caudal fin emarginate with angular lobes, its length 3.41 ( ) in SL; fourth pectoral ray longest, 3.07 ( ) in SL; pelvic spine 1.73 ( ) in HL; first soft ray of pelvic fin forming filamentous tip, 2.80 ( ) in SL. Colour in life (from underwater photograph): adults (Fig. 2) generally brown with darker scale margins forming transverse lines on body; about 10 large, pinkish to magenta spots scattered on operculum, also a prominent bluish black spot (about one- third to nearly half size of pupil), on upper margin of operculum, immediately anterior and slightly below lateral line origin; dorsal and anal fins brownish to slightly translucent posteriorly and with fine blue margin (except along posterior border); caudal fin pale yellow, grading to translucent posteriorly; pelvic fins brownish to translucent with fine blue anterior margin; pectoral fins translucent with yellowish hue, a prominent blackish spot at base of uppermost rays (fish in Fig. 2 also has about five small dark spots on middle and lower portion of fin base). Juveniles (Fig. 3) generally blue-grey on head and body except bright yellow on lips, side of snout, abdomen, and pectoral region; a pair of bright blue stripes from snout through eye and scattered small blue spots on forehead and nape; cheek and operculum with relatively large magenta spots and prominent dark blue spot on upper margin of operculum, immediately anterior and slightly below lateral line origin; dorsal fin blue-grey grading to translucent yellow posteriorly with blue-rimmed, black spot (ocellus) between second and eighth soft rays; anal fin yellow 80

7 Gerald R. Allen and John E. Randall Fig. 4. Pomacentrus bipunctatus, underwater photograph of subadult, approximately 55 mm total length, Kwajalein Atoll, Marshall Islands. Photo by N. Bartlett. Fig. 5. Pomacentrus spilotoceps, underwater photograph of juvenile, approximately 40 mm total length, Viti Levu, Fiji. Photo by G. R. Allen. 81

8 Two new species of damselfishes (Pomacentridae) from Micronesia Fig. 6. Pomacentrus amboinensis, underwater photograph of adult, approximately 80 mm total length, Milne Bay Province, Papua New Guinea. Photo by G. R. Allen. with pale blue submarginal stripe; both dorsal and anal fins with fine blue margin; caudal fin pale yellow with bluish streaks, becoming translucent posteriorly; pelvic fins bright yellow with fine blue anterior margin; pectoral fins translucent with yellow hue, a prominent blackish spot at base of uppermost rays. Subadults (Fig. 4) are similar to juveniles, but lack the dorsal ocellus and have a slightly purplish hue on the body. The transverse lines on the body that are typical of adults are also more vivid. In addition, subadults sometimes exhibit blue spots on the posterior body scales, as well as 1-3 submarginal bluish stripes on the dorsal and anal fins. Colour of holotype in alcohol: generally pale brown on head and body with narrow darker brown lines, corresponding with each transverse scale row; a pair of dark brown spots, about equal in size (approximately one-third pupil diameter), one on upper edge of gill cover, just below origin of lateral line, and the other at base of uppermost pectoral fin rays; fins translucent tan; membranes of spinous portion of first dorsal fin with inconspicuous narrow blackish margin. Paratypes are similar in colour, except juveniles display a prominent ocellus on the soft dorsal fin, generally extending between the third and eighth rays, but sometimes between the second and ninth rays in very small individuals. This feature generally persists until a size of about 45 mm SL. Comparisons The new species is similar to Pomacentrus spilotoceps Randall (2002) from Fiji and Tonga. The following distinctive markings are shared by both species: juvenile ocellus on soft dorsal fin, relatively large dark spot on upper operculum and upper pectoral fin base, bluish submarginal stripes on dorsal and anal fins, and large pale spots on cheek and operculum. However, there appears to be a significant difference in the number of pectoral fin rays (17 for P. bipunctatus and 18 or 19 rays for P. spilotoceps). There also appears to be a modal difference in the number of tubed lateral line scales (usually 16 or 17 for P. bipunctatus and 18 for P. spilotoceps, except one of five specimens with 17). The two species also show significant differences in juvenile and subadult colour patterns. The youthful stages of P. spilotoceps (Fig. 5) lack the blue and yellow hues that are so vivid in similar-sized individuals of P. bipunctatus. Finally, there is a consistent difference in the shape of the dark spot on the upper operculum. The spot is basically round in P. bipuncatus compared to the vertically elongate marking in P. spilotoceps. This difference is apparent in adults as well as juveniles. We have examined the four type specimens of P. spilotoceps (see Randall, 2002 for details) as well as a single non-type specimen, 53 mm SL, from Tongatapu deposited at BPBM. Pomacentrus bipunctatus was initially identified by the authors as a colour variant of P. amboinensis Bleeker. Although this species shares similar mor- 82

9 Gerald R. Allen and John E. Randall phometric and meristic features, it shows marked colour pattern differences (Fig. 6). It is generally pale yellow overall, with smaller, less vivid spots on the upper operculum and pectoral fin base. Moreover, it is usually associated with sandy substrates on the edge of reefs, rather than on the reef itself as is the case for P. bipunctatus. Distribution and habitat Pomacentrus bipunctatus is known from the Marshall Islands at Enewetak and Kwajalein atolls, and also from Truk in the eastern Caroline Islands. It occurs in lagoonal habitats on coral reef substrates, often on pinnacle or patch reefs at depths between 5 and 43 m. Etymology This species is named Pomacentrus bipunctatus with reference to the pair of dark spots on the upper operculum and upper pectoral fin base, which is its most distinctive marking and a feature lacking in other pomacentrids from the Marshall and eastern Caroline Islands. Pomacentrus yoshii n. sp. Figs. 7-8; Tables I and III Holotype: BPBM 39299, 60.0 Majuro Atoll, Caroline Islands: outer reef slope off Calalen Islet, m, hand net, B.D. Greene, 30 December Paratypes (all from Majuro Atoll, Marshall Islands): BPBM 9660, 42.9 mm SL, Majuro Island, near west end of airstrip, 17 m, spear, J. E. Randall, 1 April, 1970; CAS , 2 specimens, mm SL, pinnacle reef in lagoon ( N, E), 4-6 m, spear, J. E. Randall, 13 May 2004; MNHN , 2 specimens, mm SL, same collecting data as CAS paratypes; USNM , 41.1 mm SL, collected with holotype; USNM , 66.9 mm SL, same collecting data as CAS paratypes; WAM P , 2 specimens, mm SL, lagoon pinnacle off Enemonet Islet, m, hand net, B. D. Greene, 30 December Diagnosis Dorsal rays XIII,13-14; anal rays II,14-15; pectoral rays 17-19; tubed lateral line scales 16-19; several scales usually evident on suborbital; gill rakers (total 22-24); body depth in SL; colour in life generally yellow including dorsal, anal and caudal fins, with variable amount of brown and narrow dark brown scale margins on upper two-thirds of body; anterior portion of head (including lips, snout, Fig. 7. Pomacentrus yoshii, holotype, 59.9 mm SL, Majuro Atoll, Marshall Islands. Photo by B. D. Greene. 83

10 Two new species of damselfishes (Pomacentridae) from Micronesia Table III. Proportional measurements of selected type specimens of Pomacentrus yoshii as percentage of the standard length. Holotype Paratype Paratype Paratype Paratype Paratype BPBM WAM MNHN MNHN WAM BPBM P P Standard length (mm) Body depth Body width Head length Snout length Orbit diameter Interorbital width Upper jaw length Caudal peduncle depth Caudal peduncle length Predorsal length Preanal length Prepelvic length Length dorsal fin base Length anal fin base Length pectoral fin Length pelvic fin Length pelvic fin spine Length first dorsal spine Length sixth dorsal spine Length last dorsal spine Length longest dorsal ray Length first anal spine Length second anal spine Length longest anal ray Length caudal fin Caudal concavity cheek, interobital) blue to blue-grey; blue spotting on nape and small irregular blue spots on opercle and immediately above pectoral fin base; intense black spot covering base of each pectoral fin. Description Dorsal rays XIII,14 (XIII,13-14); anal rays II,14 (II,14-15); all dorsal and anal soft rays branched, the last to base; pectoral rays 18 (17-18), the upper and lowermost pairs unbranched; pelvic rays I,5; principal caudal rays 15, the median 13 branched; upper and lower procurrent caudal rays 4, the posteriormost segmented; scales in longitudinal series 27; tubed lateralline scales 16 (16-19); posterior midlateral scales with a pore or deep pit (in continuous series) 8 (6-8); scales above lateral line to origin of dorsal fin 3; scales above lateral line to base of middle dorsal spine 1.5; scales below lateral line to origin of anal fin 8.5; gill rakers ( ), total rakers 24 (22-24). Body ovate, the depth 1.93 ( ) in SL, and compressed, the width 2.59 ( ) in body depth; HL 3.41 ( ) in SL; dorsal profile of head evenly-rounded from dorsal fin origin to snout; snout shorter than orbit, its length 3.33 ( ) in HL; orbit diameter 2.63 ( ) in HL; interorbital space convex, its width 2.64 ( ) in HL; caudal peduncle depth 1.75 ( ) in HL; caudal peduncle length 2.19 ( ) in HL. Mouth terminal, small, and oblique, forming an angle of about 38 to horizontal axis of head and body; maxilla reaching a vertical about even with anterior edge of orbit, the upper-jaw length 3.03 ( ) in HL; teeth mainly uniserial except for a few slender buttress teeth in spaces between main row of teeth at front of jaws; teeth incisiform to conical in shape, about 40 in each jaw of holotype (excluding buttress teeth). Tongue triangular with rounded tip, set far back in mouth. Gill rakers long and slender, the longest on lower limb near angle about three-fourths length of longest gill filaments. Nostril round with slightly raised rim, level with lower edge of pupil and about midway between anterior edge of eye and upper lip. 84

11 Gerald R. Allen and John E. Randall Fig. 8. Pomacentrus yoshii, underwater photo of adult, approximately 70 mm total length, Majuro Atoll, Marshall Islands. Photo by S. Yoshii. Fig. 9. Pomacentrus philippinus, about 70 mm SL, Madang, Papua New Guinea. Photo by G. R. Allen. 85

12 Two new species of damselfishes (Pomacentridae) from Micronesia Opercle ending posteriorly in a flat spine, the tip obtuse, barely projecting from beneath a large scale; margin of preopercle with 19 serrae on left side of holotype (9-17 in paratypes the number generally increasing with growth); preorbital with a single serra separated by a notch from suborbital series (serra poorly developed or absent in paratypes); lower edge of suborbital smooth or with slight crenulations. Scales finely ctenoid; head scaled except lips, tip of snout, and preorbital; several scales usually evident on suborbital, but are easily lost during specimen collection or processing); a scaly sheath at base of dorsal and anal fins, averaging about one-half pupil width at base of dorsal fin and about the same width at base of anterior part of anal fin and gradually tapering in width posteriorly; a column of scales on each membrane of dorsal and anal fins, narrowing distally, those on spinous portion of dorsal fin progressively longer, reaching at least two-thirds distance to spine tips on posterior membranes, slightly farther on anterior soft rays, then gradually shorter on posterior part of fin; small scales on caudal fin extending about threefourths distance to posterior margin; small scales on basal one-fifth of pectoral fins; a cluster of several scales forming median process, extending posteriorly from between base of pelvic fins, its length about half that of pelvic spine; axillary scale above base of pelvic spine about one-third length of pelvic fin. Origin of dorsal fin over first or second tubed lateral line scale, the predorsal distance 2.50 ( ) in SL; base of soft portion of dorsal fin contained about 2.2 times in base of spinous portion; dorsal fin spines gradually increasing in length to last spine; first dorsal spine 4.36 ( ) in HL; sixth dorsal spine 2.15 ( ) in HL; last dorsal spine 1.70 ( ) in HL; membranes of spinous portion of dorsal fin incised near spine tips; fifth or sixth dorsal soft ray longest, 0.99 ( ) in SL; first anal spine 3.74 ( ) in HL; second anal spine 1.62 ( ) in HL; longest (seventh- eighth) anal soft ray 1.10 ( ) in HL; caudal fin emarginate with angular lobes, its length 2.70 ( ) in SL; fourth pectoral ray longest, 3.05 ( ) in SL; pelvic spine 1.65 ( ) in HL; first soft ray of pelvic fin forming filamentous tip, 3.33 ( ) in SL. Colour of holotype in alcohol: generally brownish tan on head and upper two-thirds of body, grading to yellowish tan ventrally; small, faint, irregular darker brown spots on opercle and immediately above pectoral fin base; anus and genital papilla dusky to blackish; fins translucent yellowish except pelvics slightly dusky with outer half of first ray intensely blackish; membranes of spinous portion of first dorsal fin with narrow blackish margin and anterior edge of anal fin narrowly black; pectoral fin with prominent black spot covering base as well as outer portion of axil. Paratypes are generally darker, brown, particularly on upper half of body, with narrow dark brown scale margins. The 41.1 and 49.9 mm SL paratypes lack yellowish tan shades ventrally. The 42.9 mm SL paratype, which has been preserved for more than 30 years, is uniform tannish brown with translucent pale tan fins, except for the dark brown spot on the pectoral fin base. Colour of freshly collected holotype (Fig. 7): generally bright yellow including dorsal, anal, and caudal fins, except brownish on top of head and narrow dark brown scale margins on upper two-thirds of body; blue spotting on nape and small irregular blue spots on opercle and immediately above pectoral fin base; pelvic fins yellow with black anterior margin; pectoral fins translucent with intense black spot covering base. There appears to be considerable variation in the live colour pattern, especially the amount of brown on the upper two-thirds of the body. For example, the individual appearing in Fig. 8 shows far less yellow. In addition, the anterior portion of the head (including lips, snout, cheek, interobital) is generally blue to blue-grey and there is a bright blue ring encircling the pupil and a vivid blue stripe on the upper edge of the iris. Comparisons The combination of a largely yellowish body and a black spot covering the pectoral fin base is unique among Pacific Pomacentrus. The only species with a similar apperance are P. pikei Bliss and P. sulfureus Klunzinger from the western Indian Ocean. Both are easily distinguished on the basis of dorsal spine count (XIV versus XIII for P. yoshii). Pomacentrus pikei is further distinguished by a small spot that is restricted to the uppermost portion of the pectoral fin base. Pomacentrus yoshii appears to be most closely related to Pomacentrus philippinus Evermann and Seale (Fig. 9), which is widespread in the eastern Indian Ocean and western Pacific. The two species, although differing significantly in colour, have similar meristic and morphometric features. Most importantly, they both have scales on the posterior suborbital series, a condition that is relatively rare for the genus. Although this feature is well-developed on the holotype of P. yoshii and represented by at least a few scales on four of the nine paratypes, it is absent in the remaining paratypes. It appears that these scales are easily dislodged during collection and processing. Distribution and habitat Pomacentrus yoshii is currently known only from the southern Marshall Islands at Majuro and Mili Atoll. It was not found in the northern Marshalls at Enewetak Atoll, the site of extensive fieldwork by both authors. This common coral reef species is the most abundant Pomacentrus at Majuro, being found on both lagoon and outer reefs at depths between m and m in these respective habitats. Etymology 86

13 This species is named Pomacentrus yoshii in honour of Satoshi Yoshii, who provided the logistic arrangements for the collection of many of the type specimens. The surname Yoshii, which is spelled with a double i ending, is treated as a noun in apposition. Acknowledgements We thank David Catania (CAS), Jeff Clayton (USNM), Glenn Moore (WAM), and Patrice Pruvost (MNHN) for providing registration numbers. Arnold Suzumoto (BPBM) sent loan material to the first author. Special thanks are due Brian Greene for collecting the holotype and three paratypes of Pomacentrus yoshii. Nathan Bartlett, Brian Greene, and Satoshi Yoshii generously provided photographs of the new species. References Allen G. R Damselfishes of the World. Mergus, Melle, Germany, 271 pp. Allen, G. R A new species of damselfish (genus Pomacentrus) from north-western Australia. Rec. West. Aust. Mus.,15 (4): Allen, G. R Two new species of damselfishes (Pomacentrus), with comments on the validity of two additional pomacentrid fishes. Revue Français d Aquariologie, 20 (1): Allen, G. R Two new species of damselfishes (Pomacentridae) from Indonesian seas. Revue Français d Aquariologie, 21 (3-4): Allen, G. R Three new species of damselfishes (Pomacentridae) from Indonesia and eastern Papua New Guinea. Revue Français d Aquariologie, 25 (3-4): Allen, G. R Descriptions of two new species of damselfishes (Pomacentridae: Pomacentrus) from Madagascar. aqua, Journal Ichthyology and Aquatic Biology, 6 (2): Allen, G. R Pomacentrus aurifrons, a new species of damselfish (Pomacentridae) from Melanesia. Zootaxa, 399: 1-7. Allen, G. R. & J. E Wright Description of a new species of damselfish (Pomacentridae: Pomacentrus) from Rodrigues Island, Indian Ocean. aqua, Journal Ichthyology and Aquatic Biology, 7 (4): Randall, J. E Two new damselfishes of the genus Pomacentrus from the south-west Pacific. aqua, Journal Ichthyology and Aquatic Biology, 5 (4): Gerald R. Allen and John E. Randall 87