Two new species of damselfishes (Pomacentridae: Chromis) from Indonesia.

INTRODUCTION

The pomacentrid genus Chromis Cuvier, 1814 is abundant throughout tropical and warm temperate seas (Allen 1991). The group is particularly conspicuous on coral reefs of the Indo-west and central Pacific region, typically found in large mid-water feeding aggregations. Similar to most pomacentrids, the majority of Chromis are restricted to depths of less than 30 m, with maximum species diversity occurring in considerably shallower depths (in about 5-18 m). Sun-drenched shallow reefs provide optimum conditions for benthic algal growth as well as supporting a diverse community of small invertebrates, both crucial components in the diet of many pomacentrids. The general lack of filamentous algae below 40-50 m depth in particular seems to be a limiting factor in the depth distribution of most damselfish species, although the structural matrix of the reef that provides shelter and nest sites, also decreases rapidly with increasing depth. Chromis are primarily zooplankton feeders, a trait that has allowed penetration well beyond depths frequented by most pomacentrids. Deep trawling, submarine observations (Colin, personal communication), the use of mixed-gas SCUBA for deep diving (Pyle, personal communication), as well as standard SCUBA diving by the authors to 50-70 m depths reveal that some Chromis are restricted to depths below 50 m and may routinely penetrate to at least 175 m. Consequently a large proportion of recent pomacentrid discoveries (e.g. Pyle et al. 2008, Allen & Erdmann 2008), including one of the new species described herein, involve deep-dwelling Chromis, and many more can be expected as deep reef exploration continues to expand.

The genus Chromis, which is the largest in the family, now contains 94 species (including the new taxa described herein). Allen (1991) provided photos and a brief diagnosis for 75 of the 76 described species (C. dispilus Griffin, 1923 from New Zealand unintentionally omitted). An additional 17 species were described in recent years (Randall & McCosker 1992, Randall 1994, Moura 1995, Randall 2001, Allen & Randall 2004, Lecchini & Williams 2004; Senou & Kudo 2007, Pyle et al. 2008, Allen & Erdmann 2008). In addition, Allen (1993) showed that C. megalopsis Allen, 1976 from Western Australia is a junior synonym of C. mirationis Tanaka, 1917 of southern Japan.

The present paper describes two new species that were collected with spear and rotenone during recent surveys at Nusa Penida (near Bali) and Cenderawasih Bay, West Papua during November 2009. The Nusa Penida fish was first mistaken for Chromis analis (Cuvier, 1830), a similar co-occurring species, but we noted it differed by having a larger size and different caudal-fin colouration. It was found in areas of cool upwelling at Nusa Penida and based on photographic evidence is also present at Japan, providing additional evidence for the occurrence of warm-temperate Japanese species on the reefs exposed to frequent cold-water upwelling in the deep straits that surround Bali.

The discovery at Cenderawasih Bay was made in connection with our on-going studies of the Bird's Head Region of West Papua. This large (approximately 59,000 [km.sup.2]) bay situated on New Guinea's north coast separates the Bird's Head or Vogelkop Peninsula from the main body of the island. Results of two (2006 and 2008) field trips co-sponsored by the Cenderawasih Bay National Park Authority, the State University of Papua and Conservation International revealed a rich reef community with several unique peculiarities indicative of isolation from neighbouring areas in the geological past. The most obvious of these included at least seven new fishes and 18 new coral species that appear to be endemic to the bay, additional fishes that occur widely in neighbouring regions, but exhibit unusual colour variation in the bay, and several deep-reef fishes that occur in unusually shallow water within the bay. Moreover, a genetic study of connectivity patterns among marine organisms by Paul Barber of the University of California at Los Angeles and Hamid Toha of the State University of Papua (Barber, personal communication) has noted the presence of distinctive clades in Cenderawasih Bay for several molluscs and crustaceans. Based on this evidence, we hypothesize that the inner portion of the bay was essentially isolated for a substantial period over the past five million years (Allen & Erdmann 2008).

MATERIALS AND 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 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 "0.5" 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.

Counts and proportions appearing in parentheses apply to the range for the paratypes if different from the holotype. Proportional measurements expressed as percentage of the standard length are provided in Tables I-II. Type specimens are deposited at Pusat Penelitian dan Pengembangan Oseanologi, Jakarta, Indonesia (NCIP), United States National Museum of Natural History, Washington, D.C. (USNM), and the Western Australian Museum, Perth (WAM).

Table I. Proportional measurements of selected type specimens of Chromis
albicauda as percentage of the standard length.

              Holotype  Paratype  Paratype  Paratype  Paratype  Paratype
                NCIP      NCIP      WAM       USNM      USNM      USNM
                6350      6351    P.33101    391796    391796   P.33101

Standard         133.7     131.8     127.0     120.5      81.5      79.6
length (mm)

Body depth        53.3      55.1      54.0      55.5      55.2      51.8

Body width        21.7      21.5      21.5      19.4      19.4      18.7

Head length       32.2      32.0      32.4      30.6      32.0      31.0

Snout length       8.6       8.4       9.0       9.1       7.2       6.9

Orbit              9.7      10.0      10.3       9.6      11.3      11.1
diameter

Interorbital       9.7      10.4      10.9      10.8       9.8       9.4
width

Depth of          15.4      15.6      17.2      15.8      16.6      16.3
caudal
peduncle

Length of         10.8      10.6      10.3      11.2      12.0      12.2
caudal
peduncle

Upper jaw         10.2      10.1      10.4      11.0       9.8      10.6
length

Predorsal         43.4      41.3      42.8      43.3      42.8      42.0
distance

Preanal           72.6      72.4      71.1      69.4      71.0      74.4
distance

Prepelvic         44.6      44.7      43.1      42.1      42.0      47.1
distance

Length of         62.7      62.0      63.4      63.7      62.3      58.5
dorsal fin
base

Length of         23.6      24.7      25.6      23.8      24.9      24.6
anal fin
base

Pectoral fin      36.2      34.6      34.4      34.5      35.7      33.4
length

Pelvc fin         32.8      30.3      29.1      32.3      34.6      33.3
length

Pelvic fin        14.9      15.0      17.4      16.9      18.5      17.8
spine length

1st dorsal         7.1       7.1       6.9       7.2       8.5       8.4
spine

2nd dorsal        12.7      12.1      11.5      11.4      12.6      13.4
spine

7th dorsal        18.1      18.4      18.6      18.2      18.8      18.7
spine

Last dorsal       14.8      12.9      14.3      13.4      15.0      14.1
spine

Longest soft      20.8      20.9      20.9      22.0      22.7      21.4
dorsal ray

1st anal           8.3       6.4       7.2       8.7       9.0       7.8
spine

2nd anal          20.9      18.7      19.1      18.9      21.7      19.5
spine

Longest soft      20.4      18.8      19.1      20.4      22.1      23.1
anal ray

Caudal fin        26.2      30.0      24.5      29.8      30.8      33.7
length

Caudal            10.8      12.3       7.2       8.1      12.4   damaged
concavity

Table II. Proportional measurements of type specimens of Chromis unipa
as percentage of the standard length.

                       Holotype  Paratype  Paratype  Paratype  Paratype
                         NCIP      WAM       WAM       WAM       WAM
                         6349    P.33043   P.33043   P.33043   P.33043

Standard length (mm)       50.4      47.5      44.1      43.2      42.8

Body depth                 46.0      49.3      47.6      46.8      46.5

Body width                 16.9      18.9      17.0      18.1      17.3

Head length                32.7      32.8      31.7      32.4      32.2

Snout length                5.8       6.9       6.6       6.7       5.4

Orbit diameter             13.3      12.2      13.4      13.0      12.4

Interorbital width          8.9       8.8       8.2       7.6       7.7

Depth of caudal            13.5      13.7      14.5      14.1      14.3
peduncle

Length of caudal           12.3      11.4      11.3      12.0      13.8
peduncle

Upper jaw length            9.3       9.7      10.0       9.7       9.6

Predorsal distance         42.7      41.5      40.8      40.0      42.1

Preanal distance           71.6      68.4      70.7      70.6      70.8

Prepelvic distance         41.3      38.7      41.3      42.1      41.1

Length of dorsal fin       60.7      63.2      58.7      61.1      59.1
base

Length of anal fin         21.4      21.9      22.0      22.2      19.9
base

Pectoral fin length        35.7      30.1      33.1      31.9      35.3

Pelvic fin length          34.5      26.3      32.9      32.4      32.7

Pelvic fin spine           19.0      17.9      16.8      17.1      18.5
length

1st dorsal spine            6.0       5.7       5.7       6.3       6.5

2nd dorsal spine           10.3       9.5      10.7      10.9      11.9

7th dorsal spine           15.3      16.0      14.5      14.4      15.2

Last dorsal spine          10.1      11.6      11.1      11.6      11.2

Longest soft dorsal        17.1      18.9      17.9      19.2      17.3
ray

1st anal spine              5.6       6.3       6.3       6.5       6.5

2nd anal spine             23.4      23.4      22.0      21.3      22.0

Longest soft anal ray      21.0      21.5      20.9      19.9      21.5

Caudal fin length          39.9      35.8      37.9      36.6      35.0

Caudal concavity           21.6      19.4      20.6      19.7      20.6

Chromis albicauda n. sp. (Figs 1-2, 4-5; Table I)

[FIGURE 1 OMITTED]

[FIGURE 2 OMITTED]

[FIGURE 4 OMITTED]

Holotype: NCIP 6350, 133.7 mm SL, Crystal Bay, 8[degrees]42.887'S 115[degrees]27.331'E, Nusa Penida, Indonesia; 30 m depth, spear, M. Erdmann, 28 November 2008.

Paratypes (collected with holotype): NCIP 6351, 131.8 mm SL; USNM 391796, 2 specimens, 81.5-120.5 mm SL; WAM P.33101-005, 5 specimens, 79.6-127.0 mm SL.

Diagnosis: Dorsal rays XIII,12 (rarely 11); anal rays II,12 (rarely 11); pectoral rays 18-20; spiniform caudal rays 3; tubed lateral-line scales 17-19; gill rakers 7-8 + 24-26, total rakers 24-26; body depth 1.8-1.9 in SL; edge of suborbital hidden by scales; 4-5 scale rows on anterior portion of preobital; generally yellow in life, grading to brown on upper back with abruptly white caudal fin; blackish anal opening (also evident in preservative).

Description: Dorsal rays XIII,12 (one paratype with XIII,11); anal rays II,12 (one paratype with II,11); all dorsal and anal soft rays branched (except first dorsal ray unbranched in one paratype), the last dorsal and anal rays branched to base; pectoral rays 19 (18-20), the upper and lowermost pair unbranched; pelvic rays I,5; principal caudal rays 15, the upper and lowermost unbranched; spiniform caudal rays 3, followed by 2 accessory segmented rays; scales in longitudinal series 28; tubed lateral-line scales 19/18 (17-19); posterior midlateral scales with a pore or deep pit (in continuous series) 8 (6-8); scales above lateral line to origin of dorsal fin 2.5; scales above lateral line to base of middle dorsal spine 2.5; scales below lateral line to origin of anal fin 8.5; gill rakers 7-8 + 16-19, total rakers 23-26; branchiostegal rays 6; supraneural (predorsal) bones 3; vertebrae 11 + 15.

Body moderately deep, depth 1.9 (1.7-1.9) in SL, and compressed, the width 2.5 (2.5-2.9) in body depth; head length 3.1 (3.1-3.3) in SL; dorsal profile of head evenly rounded; snout shorter than orbit diameter, its length 3.7 (3.4-4.5) in head length; orbit diameter 3.3 (2.8-3.2) in head; interorbital space convex, its width 3.3 (2.8-3.3) in head; caudal-peduncle depth 2.1 (1.9-2.1) in head; caudal-peduncle length 3.0 (2.5-3.1) in head.

Mouth terminal, small, and oblique, forming an angle of about 30[degrees]-32[degrees] to horizontal axis of head and body; posterior edge of maxilla reaching a vertical slightly behind anterior edge of pupil, the upper-jaw length 3.2 (2.8-3.3) in head; teeth multiserial, an outer row of conical teeth in each jaw, largest anteriorly; 22 (17-23) upper and 20 (17-20) 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 two-thirds to three-fourths length of longest gill filaments; nostril with a fleshy rim, more elevated on posterior edge and located at level of middle of pupil, slightly closer to orbit than edge 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, the anterior margin extending to level of middle of pupil; preorbital relatively broad, its width tapering posteriorly, with 4-5 irregular scale rows at widest point; suborbital covered with 1-2 rows of small scales that obscure its lower margin.

Scales finely ctenoid; anterior lateral line ending beneath base of last dorsal spine; head scaled except lips, chin, 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 one-half 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 and anal fins, narrowing distally, those on spinous portion of dorsal progressively longer, reaching about two-thirds distance to spine tips on posterior membranes, then progressively shorter on soft portion; small scales on caudal fin extending nearly to posterior margin; small scales on basal one-fourth of pectoral fins; series of progressively tapering scales forming median scaly process posteriorly from between base of pelvic fins, its length slightly more than one-third that of pelvic spine; axillary scale above base of pelvic spine about one-half length of spine.

Origin of dorsal fin above third lateral-line scale, the predorsal distance 2.3 (2.3-2.4) in SL; base of soft portion of dorsal fin contained 2.7 (2.6-2.7) times in base of spinous portion; first dorsal spine 4.5 (3.7-4.7) in head; second dorsal spine 2.5 (2.3-2.9) in head; fourth to ninth dorsal spines subequal, the longest 1.8 (1.6-1.7) in head; last dorsal spine 2.2 (2.0-2.5) in head; membranes of spinous portion of dorsal fin moderately incised; third to fifth dorsal soft rays longest, 1.5 (1.3-1.6) in head; first anal spine 3.9 (3.1-5.0) in head; second anal spine 1.5 (1.4-1.7) in head; first three anal soft rays subequal, the longest 1.6 (1.3-1.7) in head; caudal fin forked, its length 3.8 (2.7-4.1) in SL, the caudal concavity 3.0 (2.6-4.5) in head; fourth pectoral ray longest, 2.8 (2.7-3.0) in SL; pelvic spine 2.2 (1.6-2.1) in head; first soft ray of pelvic fin filamentous, 3.1 (2.8-3.4) in SL.

Colour of holotype in alcohol (Fig. 1): Overall yellowish tan grading to brown on upper third of head and body; scaly sheath on basal half of spinous dorsal fin brown, the brown colouration also extending to base of soft dorsal fin, which is otherwise pale tan; caudal fin pale tan; anal fin mainly pale tan, except light brown on basal portion; pectoral and pelvic fins yellowish tan, pectoral-fin base with small brown spot on upper edge; small blackish blotch covering anal opening.

Colour in life (Fig. 2): Overall yellow except caudal fin abruptly white; upper third of body grading to brown and scales on lower two-thirds of side with narrow brown margins; dorsal fin brown on basal half, yellow on outer portion, except distal half of soft dorsal fin translucent; anal and pectoral fins yellow; pectoral fins translucent yellowish, the upper edge of its base brown, small blackish blotch covering anal opening. Chromis albicauda was observed to instantaneously "switch" its white tail on and off underwater. When the normal white colour is temporarily turned off the tail is yellow and the fish is difficult to distinguish from the similar C. analis (Fig. 3).

[FIGURE 3 OMITTED]

Remarks: Chromis albicauda is very similar in general appearance to C. analis, which co-occurs at Bali and is widely distributed in the Western Pacific from the Great Barrier Reef of Australia to Japan, ranging east to Micronesia (except Marshall Islands) and Fiji. Both species have an overall yellow colouration, brownish back and brown dorsalfin base (compare Figs 1 and 3). However, C. albicauda differs most noticeably in possessing an abruptly white caudal fin, compared to that of C. analis, which is yellow (same as adjacent body colour) with a translucent margin. In preservative (Fig. 4) the two species are further distinguished by the blackish blotch that covers the anal opening of C. albicauda, a feature lacking in C. analis. Also, the brown spot on the upper pectoral-fin base of C. albicauda is small and inconspicuous, being mainly confined to the dorsal edge of the fin base compared to the much larger, wedge-shaped spot of C. analis that covers the uppermost portion of the fin base. There is also an important difference related to the pattern of scales on the preorbital and sub-orbital series (Fig. 5). The preorbital of C. albicauda is densely covered with 4-5 irregular rows of small scales that taper posteriorly to 1-2 rows on the suborbital. In comparison, the preorbital of C. analis has 1-2 rows of larger scales on the preorbital and a single row on the suborbital. Furthermore, the lower margin of the suborbital is obscured by scales in C. albicauda, but is exposed in C. analis. Morphometric differences include consistently taller dorsal spines in C. albicauda. For example the length of the first spine ranges from 3.7 to 4.7 in the HL for C. albicauda compared to 5.1-6.0 in C. analis and that of the longest spine ranges from 1.6-1.8 (usually 1.6-1.7) compared to 1.8-2.0. Meristic differences include lateral line scales (17-19 for C. albicauda versus 15-16 for C. analis) and a tendency towards lower gill raker counts in C. albicaudata (average total rakers on the first branchial arch 25.0 versus 27.0, and rakers on lower limb 17.5 versus 19.8).

Finally, there is a significant size difference in the two species (Fig. 4) with the largest known adults reaching 133.7 mm SL in C. albicauda and about 100 mm SL for C. analis, although the latter fish is often reported reaching a larger size in the literature due to confusion between the two species. Comparisons are based on five specimens of C. analis, 82.0-92.4 mm SL, from the Watubela Islands, Maluku Province, Indonesia (WAM P.33085-006).

Chromis albicauda is also similar to C. pembae Smith, 1960 from the western Indian Ocean, Red Sea, and southern Arabian Peninsula. Both species have a similar shape and exhibit a white caudal fin, although the overall colour of C. pembae is mainly brown or yellowish brown rather than yellow. There are also differences in number of soft anal rays (11 for C. pembae versus a usual count of 12) and total gill rakers on the first gill arch (27-31 rakers, usually 28-30, for C. pembae versus 24-26). Moreover the preorbital/suborbital scalation of C. pembae is similar to that of C. analis as illustrated in Fig. 5. There is also a substantial size difference for the two species with C. pembae attaining a maximum standard length of approximately 95.0 mm compared to at least 133. 3 mm for C. albicauda.

Distribution and habitat: The new species was commonly observed in areas of cool (18[degrees]-24[degrees]C) upwelling along the northern and western shores of Nusa Penida at depths between about 25-50 m, although we observed a pair in only 10 m on one occasion. The species typically forms aggregations, which feed high in the water column on zooplankton when currents are strong. In addition to its occurrence at Nusa Penida (a small island lying approximately 15 km east of Bali), C. albicauda apparently also occurs in southern Japanese seas based on photographic evidence (Masuda & Kobayashi 1994, Kuiter & Debelius 2006). Therefore, it likely has a disjunct distribution associated with cool temperature regimes. At least two other species found at Nusa Penida also have Japanese distributions including Apogon schlegeli Bleeker, 1854, and labrid Bodianus masudai Araga & Yoshino, 1975. Nusa Penida is characterized by cold upwelling and populations of typically cool water species are therefore able to thrive. The presence of the acanthurid Prionurus chrysurus Randall, 2001 at Nusa Penida (also Bali, Lombok and Komodo) provides an additional example of this phenomenon. The genus Prionurus Lacepede, 1804 typically inhabits lower latitudes with representatives known from Japan, temperate Australia, and the Eastern Pacific Ocean.

Etymology: This species is named albicauda (Latin: "white tail") with reference to the diagnostic feature that separates it from the similar C. analis.

Chromis unipa n. sp. (Figs 6-7; Table II)

[FIGURE 6 OMITTED]

[FIGURE 7 OMITTED]

Holotype: NCIP 6349, 50.4 mm SL, Tridacna Reef, 2[degrees]29.672'S 134[degrees]58.990'E, eastern side of Cenderawasih Bay, Papua Barat Province, Indonesia; 45-60 m depth, rotenone, M. Erdmann and G. Allen, 13 November 2008.

Paratypes (collected with holotype): WAM P.33043-002, 4 specimens, 43.2-47.5 mm SL.

Diagnosis: Dorsal rays XIV,11; anal rays II,11; pectoral rays 18; spiniform caudal rays 3; tubed lateral-line scales 14-17; gill rakers 7-8 + 19-20 = 27-28; body depth 2.0-2.2 in SL; alternating blue grey and brassy yellow stripes on side of body; abdomen and lower part of head blue grey; fins bluish except base of caudal fin brown; a prominent black spot at apex of anal fin.

Description: Dorsal rays XIV,11; anal rays II,11; all dorsal and anal soft rays branched except first dorsal ray, the last dorsal and anal rays branched to base; pectoral rays 18, the upper- and lowermost pair unbranched; pelvic rays I,5; principal caudal rays 15, the upper and lowermost unbranched; spiniform caudal rays 3, followed by 2 accessory segmented rays; scales in longitudinal series 27; tubed lateral-line scales 15 (13-15); posterior mid-lateral scales with a pore or deep pit (in continuous series) 7/6 (7); scales above lateral line to origin of dorsal fin 2.5; 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 8 + 19 = 27 (7-8 + 19-20 = 27-28; branchiostegal rays 6; supraneural (predorsal) bones 3; vertebrae 11 + 15.

Body relatively elongate, depth 2.2 (2.0-2.2) in SL, and compressed, the width 2.7 (2.6-2.8) in body depth; head length 3.1 (3.0-3.2) in SL; dorsal profile of head with a slight convexity above eye; snout shorter than orbit diameter, its length 5.7 (4.7-6.0) in head length; orbit diameter 2.5 (2.4-2.7) in head; interorbital space convex, its width 3.7 (3.7-4.2) in head; caudal-peduncle depth 2.4 (2.2-2.4) in head; caudal-peduncle length 2.7 (2.3-2.9) in head.

Mouth terminal, small, and oblique, forming an angle of about 44[degrees] to horizontal axis of head and body; posterior edge of maxilla reaching a vertical slightly behind anterior edge of pupil, the upper-jaw length 3.5 (3.2-3.4) in head; teeth multiserial, an outer row of conical teeth in each jaw, largest anteriorly; 22 upper and 20 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 three-fourths 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-half distance from front of orbit to edge 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, the anterior margin extending to level of middle of pupil; narrow suborbital covered with single row of small scales, with free lower margin extending nearly to a vertical at posterior edge of pupil.

Scales finely ctenoid; anterior lateral line ending beneath base of twelfth dorsal spine; 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 one-half 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 and anal fins, narrowing distally, those on spinous portion of dorsal progressively longer, reaching about two-thirds distance to spine tips on posterior membranes, then progressively shorter on soft portion; small scales on caudal fin extending slightly more than two-thirds 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 slightly more than one-third that of pelvic spine; axillary scale above base of pelvic spine about one-half length of spine.

Origin of dorsal fin above fourth lateral-line scale, the predorsal distance 2.3 (2.4-2.5) in SL; base of soft portion of dorsal fin contained 3.6 (3.1-4.1) times in base of spinous portion; first dorsal spine 5.5 (5.9-5.8) in head; second dorsal spine 3.2 (2.7-3.5) in head; fourth to ninth dorsal spines subequal, the longest 2.1 (2.1-2.3) in head; last dorsal spine 3.2 (2.8-2.9) in head; membranes of spinous portion of dorsal fin moderately incised; third to fifth dorsal soft rays longest, 1.9 (1.7-1.9) in head; first anal spine 5.9 (4.9-5.2) in head; second anal spine 1.4 (1.4-1.5) in head; first three anal soft rays subequal, the longest 1.6 (1.5-1.6) in head; caudal fin forked, its length 2.5 (2.6-2.9) in SL, the caudal concavity 1.5 (1.5-1.7) in head; fourth pectoral ray longest, 2.8 (2.8-3.3) in SL; pelvic spine 1.7 (1.7-1.9) in head; first soft ray of pelvic fin filamentous, 2.9 (3.0-3.8) in SL.

Colour of holotype in alcohol (Fig. 6): Generally brown, paler where scales have been dislodged; median fins also brown except outer half of soft dorsal fin and caudal fin translucent with dusky grey rays; pelvic fins light dusky brown with paler anterior margin; pectoral rays translucent with large black spot on upper half of fin base, extending onto outer face of axil.

Colour of holotype when freshly captured (Fig. 7): Head brownish dorsally and pale bluish below level of eye; about 6-7 blue spots on operculum; series of alternating blue and bronzy yellowish stripes on side, each blue stripe about half of pupil width and covering centre of each scale row; bronzy yellowish stripes slightly wider and overlapping lower and upper portions of adjacent scale rows; belly and lower portion of side (below level of lower pectoral-fin base) bluish grey; dorsal fin grey-brown with bronzy yellowish basal portion and narrow whitish margin on spinous portion, posteriormost portion of fin translucent with dusky grey rays; anal fin mainly bluish with narrow white anterior margin, large black spot distally on middle portion, and translucent on posterior margin; caudal fin yellowish brown at base of each lobe, the posterior margin broadly translucent with bluish grey rays; pelvic fins bluish white with white anterior margin; pectoral rays translucent with large black spot on upper half of fin base, extending onto outer face of axil.

Remarks: The new species is distinguished from the majority of Chromis by having 14 dorsal-fin spines instead of the usual counts of 12 or 13, rarely 15 (one species). The five species from the central and eastern Atlantic generally have 14 spines, but within the vast Indo-Pacific region only 14 currently valid species (including the new taxon) possess 14 spines. This group, which exhibits diverse morphological characters and is apparently polyphyletic, primarily inhabits either subtropical areas such as Hawaii, and Japan or is mainly confined to deep reefs in about 50-183 m depth. Pyle et al. (2008) discussed the members of the deep-dwelling complex with 14 dorsal spines, which includes C. abyssus Pyle, Earle & Greene, 2008 (Palau), C. axillaris (Bennett, 1831) (East Africa and Mauritius), C. circumaurea Pyle, Earle & Greene, 2008 (Yap, Caroline Islands), C. degruyi Pyle, Earle & Greene, 2008 (Caroline Islands), C. mirationis Tanaka, 1917 (Japan and Western Australia), C. okamuri Yamakawa & Randall, 1989 (Okinawa Trough, China Sea), C. onumai Senou & Kudo, 2007 (southern Taiwan and Izu Islands), C. planesi Lecchini & Williams, 2004 (Rapa Island, Polynesia), C. struhsakeri Randall & Swerdloff, 1973 (Hawaiian Islands), and C. woodsi Bruner & Arnam, 1979 (East Africa). The new species differs from all of these in its distinctive colour pattern of alternating blue and bronzy yellowish stripes with a large black spot on the anal fin, and from most species on the basis of its relatively low number (11) of soft dorsal and anal rays compared with the usual range of 12-14 rays. Chromis woodsi possesses 11-12 soft dorsal-fin rays, but differs in having a lower gill-raker count (23-25 versus 27-28) and a very different colour pattern (overall whitish with broad, black bar on caudal peduncle).

Of the taxa mentioned above, C. unipa appears to be most similar to C. degruyi (Fig. 8). Both species have 18 pectoral rays, relatively low lateral-line scale counts (14-17), and 27-28 gill rakers. They differ, however, in modal dorsal and anal ray counts with C. degruyi having 12 (rarely 11) compared to 11 rays in C. unipa. There are also differences in body depth and snout length. The new species has a slightly more slender body (46.0-49.3% of SL, compared to 50.1-54.4%) and shorter snout (5.4-6.9% of SL vs 7.4-8.7% of SL). The comparative data for the five type specimens of C. degruyi were taken from Pyle et al. (2008) and although the three largest individuals (76.6-81.0 mm SL) were considerably larger than our specimens of C. unipa, the two smaller specimens (38.3-38.7 mm SL) of C. degruyi exhibit a consistently deeper body (50.2-50.8% of SL) and longer snout (7.8-8.2% of SL). There are also significant colour pattern differences, although both species possess a large black spot on the upper pectoral-fin base. Chromis degruyi is basically dull brownish yellow with a thin, lavender-grey stripe on each scale row, and lacks the prominent black spot on the anal fin that is characteristic of C. unipa. Furthermore, individuals of C. degruyi under about 50 mm SL have broad yellow dorsal and ventral margins on the caudal fin and yellow pigmentation on the posterior dorsal and anal fins.

[FIGURE 8 OMITTED]

Distribution and habitat: The type locality and only known collection site of C. unipa consists of rubble and low-profile coral reef substratum at the base of a steep, nearly vertical dropoff at 42 m to at least 65 m depth. The Tridacna Reef location consists of a submerged atoll lying approximately 38.5 km directly east of the Wandamen Peninsula. The species was common and seen in the company of C. brevirostris Pyle, Earle & Greene, 2008, a species previously known from Bali, Caroline Islands (Palau to Puluwat), Marshall Islands, Vanuatu, and Fiji. The sighting of this species at Cenderawasih Bay is noteworthy as the depth range (42-65 m) was much shallower than the usual range of 90-120 m reported by Pyle et al. (2008). This observation is consistent with several other normally deep-dwelling reef species that are found in relatively shallow water at Cenderawasih Bay. Therefore, it is possible that C. unipa may be found much deeper at locations outside the bay.

Etymology: This species is named unipa with reference to the acronym for Universitas Negeri Papua (State University of Papua, Manokwari), who invited the authors to conduct an ichthyology field course that led to the discovery of this species. The University has played a critical role in training young Papuans in the natural sciences, and it is our sincere hope that this work will inspire students and lecturers at the University to actively explore the unique natural laboratory of Cenderawasih Bay at their doorstep. The name is treated as a noun in apposition.

ACKNOWLEDGEMENTS

The authors would like to thank the following agencies for supporting the rapid biodiversity assessment of Nusa Penida which led to the discovery of C. albicauda: the Ministry of Research and Technology, the Indonesian Institute of Sciences, the Ministry of Fisheries and Marine Affairs, the Bali Department of Nature Conservation (BKSDA), the Klungkung regional government, and Conservation International. Michael Cortenbach and Sven Fautz at Bali Diving Academy provided excellent logistical support for the survey as well. Iwan Dewantama and Ketut Sarjana Putra of Conservation International are owed special thanks for their efforts to organize and oversee the Nusa Penida assessment. Likewise, we gratefully acknowledge the State University of Papua (particularly Paulus Boli and Emmanuel Manangkalangi), the Cenderawasih Bay National Park Authority (particularly Kemal Amas and John Sroyer), and Conservation International (especially Chris Rotinsulu) for arranging and supporting the ichthyology field course which led to the discovery of C. unipa. We are also extremely grateful to Martha Davis and the Gordon and Betty Moore Foundation for their financial support of this capacity building course. We thank Suharsono and Rianta Afriadi of the Indonesian Institute of Sciences for their support and assistance with type specimens, and the owners, captain and crew of the MV Temu Kira for providing an excellent diving platform for the Cendrawasih field survey. Dan Polhemus provided valuable inputs on the isolation of Cendrawasih Bay from a geological perspective.

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Gerald R. Allen (1) and Mark V. Erdmann (2)

(1) Department of Aquatic Zoology, Western Australian Museum, Locked Bag 49, Welshpool DC, Perth, Western Australia 6986. E-mail: [e-mail]

(2) Conservation International Indonesia Marine Program, Jl. Dr. Muwardi No. 17, Renon, Denpasar 80235 Indonesia

Received: 27 April 2009-Accepted: 03 July 2009