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Amphiprion pacificus, a new species of anemonefish (Pomacentridae) from Fiji, Tonga, Samoa, and Wallis Island.

INTRODUCTION

The brightly coloured members of the pomacentrid tribe Amphiprionini (see Cooper et al. 2009) are well known for their commensal relationship with large sea anemones. Allen (1972, 1980) provided comprehensive reviews of the group and summary of their biology. More recently, these fishes were treated by Fautin & Allen (1992), who recognized 27 species in Amphiprion Bloch & Schneider, 1801, and one species in Premnas Cuvier, 1816. An additional species of Amphiprion was described by Allen et al. (2008).

The present paper describes a new species that was collected in 2000 at Wallis Island (about 575 km west of American Samoa) by colleague Jeff Williams of the United States National Museum. We subsequently received three additional specimens collected at Tonga. It has also been observed by the third author at several locations around American Samoa including Utelei, Aunu'u, Fagaalu, and Fagatele Bay National Marine Sanctuary. Underwater photographs also indicate its presence at Fiji, although it is apparently rare.

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 (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 bony 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; 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; 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 separated by a backslash (/) indicate values taken from both sides of the holotype.

We also conducted a molecular analysis to provide an additional set of characters on which to evaluate the specific status and evolutionary relationships of this species. Whole genomic DNA was extracted using Chelex 100 (Walsh et al. 1991). We amplified the 12s mitochondral gene using the primers CRA and CRE (Lee et al. 1995) and the following thermocycler parameters: An initial denature step of 94 [degrees] C for 3 min followed by 40 cycles of denature 30s at 94 [degrees] C, annealing 60s at 50 [degrees] C, and extension 90s at 72 [degrees] C with a 5 min extension period at 72 [degrees] C. PCR amplicons were visualized on a 1% agarose gel and enzymatically cleaned for sequencing by digestion in 5 U of exonuclease I and 0.5 U of shrimp alkaline phosphatase for 30 min at 37 [degrees] C followed by 15 min at 80 [degrees] C. Samples were precipitated using 75% isopropanol prior to sequencing. Sequencing of both forward and reverse strands was performed on a 3730XL sequencer using Big Dye 3.1 terminator chemistry (Applied Biosystems) housed at the Pritzker Laboratory for Molecular Systematics and Evolution at the Field Museum of Natural History. Sequences were edited and aligned using Geneious 4.8. Bayesian phylogenetic reconstructions were made using MrBayes (Ronquist & Huelsenbeck 2003). Because of the small number of samples involved we used the GTR+I+gamma model of evolution allowing the program to run for 2,000,000 generations with a 25% burn-in period.

We have also created a species page for the new taxon on the Encyclopedia of Life. This page will serve as a single electronic home for new information on all aspects of biology of A. pacificus including DNA sequences, evolution, ecology, and conservation status. This page may be accessed at http://eol.org/Amphiprion%20pacificus.

Proportional measurements expressed as percentage of the standard length are provided in Table I. Type specimens are deposited at the United States National Museum of Natural History, Washington, D.C. (USNM).
Table I. Proportional measurements of type specimens of
Amphiprion pacificus as percentage of the standard length.

                 Holotype   USNM     USNM     USNM
                   USNM    393561   393942   393941
                  373925

Standard length      48.3     47.9     39.7    30.9
(mm)

Body depth           46.0     40.7     38.3    42.4

Body width           18.4     17.3     14.4    18.1

Head length          30.4     30.3     29.2    32.7

Snout length          9.9      9.8     10.6    10.0

Orbit diameter        8.5      7.9      8.8    10.0

Interorbital          9.7      9.0      8.6     9.4
width

Caudal peduncle      16.6     17.7     16.1    18.4
depth

Caudal peduncle      14.7     15.0     13.9    14.2
length

Upper jaw            10.8     11.5     11.1    11.7
length

Predorsal            35.8     40.7     37.8    41.1
length

Preanal length       67.1     63.7     61.0    64.4

Prepelvic            43.5     40.3     36.5    38.2
length

Length dorsal        56.3     57.2     55.9    57.0
fin base

Length anal fin      24.4     24.6     26.7    24.6
base

Length pectoral      26.9     27.6     28.0    26.9
fin

Length pelvic        20.9     22.1     21.9    20.4
fin

Length pelvic        13.7     12.7     12.3    12.3
fin spine

Length first          5.4      5.8      6.0     6.8
dorsal spine

Length fourth         8.7      8.4      8.3     9.1
dorsal spine

Length last           7.2      6.3      5.8     5.8
dorsal spine

Length longest       15.5  damaged  damaged    13.6
dorsal ray

Length first          4.1      4.0      4.5     2.6
anal spine

Length second         8.1      7.7      6.8     7.4
anal spine

Length longest       12.8     11.7     12.6    12.9
anal ray

Length caudal        27.1     26.3  damaged    24.3
fin


Comparative material of Amphiprion akallopisos Bleeker examined (42 specimens, 29.5-75.0 mm SL): BPBM 10852, 9 specimens, 33.0-63.0, Comoro Islands; USNM 204266, 26 specimens, 31.5-75.0 mm SL; WAM P.25249-001, 5 specimens, 32.1-65.4 mm SL, Java Sea, Indonesia; WAM P. 26504-006, 49.0 mm SL, Phuket, Thailand; WAM P.26507-001, 29.5 mm SL, Similan Islands, Thailand.

Comparative material of A. sandaracinos Allen examined (13 specimens, 17.4-63.0 mm SL): BPBM 6804 (paratype), 60.8 mm SL, Manila, Philippines; BPBP 10617 (paratypes), 3 specimens, 27.0-43.3 mm SL, Manila, Philippines; USNM 147130 (holotype), 63.0 mm SL, Luzon, Philippines; USNM 160663 (paratypes), 2 specimens, 35.0-47.6 mm SL, Luzon, Philippines; USNM 160664 (paratypes), 2 specimens, 44.0-54.2 mm SL, Bolinao Bay, Philippines; WAM P.25234-001, 17.4 mm SL, Ambon, Indonesia; WAM P.25609-001, 61.0 mm SL, North West Cape, Western Australia; WAM P. 27528-001, 2 specimens, 17.5-40.2 mm SL, Manus Island, Papua New Guinea.

Amphiprion pacificus n. sp.

Pacific Anemonefish

(Figs 1-2; Tables I-III)

[FIGURE 1 OMITTED]

[FIGURE 2 OMITTED]
Table II. Summary of soft anal rays, pectoral rays, and
total gill rakers on the first branchial arch for three species
of Amphiprion. Pectoral rays for A. pacificus were recorded
from both sides of each individual.

                      Anal rays           Pectoral rays

                 12           13  14  16             17  18
A. akallopisos    2           25   1   1             23   4
A. pacificus      1            3       2              6
A. sandaracinos  14                    1              3  10

                     Gill rakers

                 17           18  19  20
A. akallopisos    3           14  11   2
A. pacificus      3            1
A. sandaracinos   9            2

Table III. Summary of diagnostic features for Amphiprion
akallopisos, A. pacificus, and A. sandaracinos.

                    A.       A. pacificus  A. sandaracinos
               akallopisos

Geographic     Indian Ocean       Central      East Indian
range                              Pacfic           region

Anterior              snout         snout        upper lip
terminus of
white stripe

Soft dorsal              19            19               18
rays (mode)

Anal rays                13            13               12
(mode)

Pectoral rays            17            17               17
(mode)

Total gill            18-19            17               17
rakers (mode)


Holotype: USNM 373925, 48.3 mm SL, Wallis Islands, Ile Uvea, west side on outer reef, north-west of Point Vaha'a'Utu, 13 [degrees] 16'50"S, 176 [degrees] 15'55"W, in spur and groove zone with abundant live coral, 6-12 m depth, rotenone, J. Williams and party, 10 November 2000.

Paratypes: USNM 393941, 30.9 mm SL, Tonga, obtained from aquarium fish exporter via Scott Michael, July 2004; USNM 39342, 39.7 mm SL, same data as previous paratype; USNM 393561, 47.9, same data as previous paratype.

Diagnosis: A species of the pomacentrid genus Amphiprion with the following combination of characters: dorsal rays IX,18-20; anal rays II,12-13; pectoral rays 17-18; tubed lateral line scales 33-48; gill rakers 5-6 + 11-12; opercular spinules 8-11; body depth 2.2-2.6 in SL; generally pinkish brown, usually grading to yellowish or orange on lower side of body including abdomen; white stripe on midline of snout extending posteriorly on forehead and along base of dorsal fin; fins whitish to semi-translucent.

Description: Dorsal rays IX, 20 (18-19, see Table II); anal rays II,12 (II,13); all dorsal and anal soft rays branched except first, last dorsal and anal rays branched to base; pectoral rays 18 (17-18, see Table II); upper and lowermost pairs unbranched; pelvic rays I,5; branched caudal rays 15; scales in longitudinal series 63/64 (51-63); tubed lateral line scales 48/42 (33-46); scales below lateral line to origin of anal fin 21 (20-21); scales above lateral line to middle of dorsal fin base 5; gill rakers on first branchial arch 6 + 12 (5-6 + 11-12).

Body ovate, depth 2.2 (2.5-2.6) in SL, and compressed, width 2.5 (2.3-2.7) in body depth; HL 3.3(3.1-3.4) in SL; forehead steeply sloped, ventral profile of head gently rounded from snout to pelvic fin origin; snout shorter than orbit, its length 3.1 (2.8-3.1) in HL; orbit diameter 3.6 (3.3-3.8) in HL; interorbital space slightly convex, its width 3.1 (3.5-4.4) in HL; caudal peduncle depth 1.8 (1.7-1.8) in HL; caudal peduncle length 2.1 (2.0-2.3) in HL.

Mouth terminal, oblique, jaws forming an angle of about 30[degrees] to horizontal axis of head and body; maxilla reaching vertical at anterior edge of pupil, upper jaw length 2.8 (2.6-2.8) in HL; teeth uniserial, consisting of about 32 (28-32) teeth in each jaw; tongue broadly rounded, papillose on dorsal surface; gill rakers moderately elongate, longest on lower limb near angle about one-half longest gill filaments; nostril round with slightly raised rim, about midway between anterior edge of eye and upper lip.

Spinules on posterior margins of interopercle, subopercle, and opercle well developed; interopercle spinules 15/16 (12-15), subopercle spinules 10/8 (8-11) and opercle spinules 10/11 (8-11); rear margin of preopercle with few weak crenulations; suborbital spinules 18/15. (10-17); cleithral spinules 9/7 (4-7); and scapular spinules 5/6 (2-6).

Scales finely ctenoid; head scaled except for lips, snout, preorbital, suborbital, chin, anterior portion of dentary, and lower/posterior margin of preopercle; transverse scale rows on cheek 6; scaly sheath at base of dorsal and anal fins, averaging about one-half eye width at base of spinous portion of dorsal fin and slightly less at base of anal fin; column of scales on each membrane of dorsal and anal fins, narrowing distally, becoming progressively longer to middle of soft portion of fin where they cover about basal half of fin, then gradually shorter on remainder of fin; small scales covering most of caudal fin, extending about two-thirds to three-fourths distance to posterior margin; small scales on basal one-fourth to one-half of middle pectoral fin rays; cluster of several scales forming median process culminating in enlarged scale between bases of pelvic fins, posteriormost scale extending slightly beyond middle of pelvic spine; axillary scale above base of pelvic spine about one-half length of pelvic fin spine.

Origin of dorsal fin over second or third lateral-line scale; predorsal distance 2.8 (2.4-2.8) in SL; preanal distance 1.5 (1.6) in SL; prepelvic distance 2.3 (2.5-2.7) in SL; bases of soft and spinous portions of dorsal fin about equal in length; dorsal fin spines gradually increasing in length to third spine, remaining spines about equal; first dorsal spine 5.7 (4.8-5.2) in HL; fourth dorsal spine 3.5 (3.5-3.6) in HL; last dorsal spine 4.2 (4.8-5.6) in HL; penultimate dorsal soft ray longest, 2.0 (2.4, but damaged in two paratypes) in HL; first anal spine 7.4 (6.4-7.6) in HL; second anal spine 3.8 (3.9-4.4) in HL; longest (penultimate) anal soft ray 2.4 (2.3-2.6) in HL; sixth or seventh pectoral ray longest, 3.7 (3.6-3.7) in SL; pelvic fin spine 2.2 (2.4-2.7) in HL; pelvic fin length 4.8 (4.5-4.9) in SL; caudal fin rounded, its length 3.7 (3.8-4.1) in SL.

[FIGURE 3 OMITTED]

Colour of freshly collected holotype (Fig. 1): pinkish brown on head and upper side, grading to yellow on lower side; dorsal, anal, and caudal fins translucent whitish to slightly pink; pelvic fins yellow; pectoral fins translucent yellowish.

Colour in life (from underwater photos, Fig. 2): generally pinkish brown, usually grading to yellow or orange on lower half of head and side; white stripe on dorsal midline of head extending from just anterior of eye to dorsal fin origin, continuing along base of dorsal fin to caudal-fin base; pelvic and pectoral fins yellow; remaining fins whitish to translucent.

[FIGURE 4 OMITTED]

Colour of holotype after eight years in alcohol: generally pale tan grading to light brown on forehead and back; fins whitish to semi-translucent. The more recently collected paratypes are similar, but slightly paler overall.

Remarks: Amphiprion pacificus is similar in appearance to A. akallopisos (Fig. 3), which ranges widely in the Indian Ocean from East Africa to western Thailand and western Indonesia, and to A. sandaracinos (Fig. 4), which occurs from Kalimantan, Indonesia to the Solomon Islands, north to the Philippines, Taiwan, and Ryukyu Islands, and south to Western Australia. The three taxa form a complex of allied species that share similar meristic and morphometric proportions, as well as similar colour patterns. They also share a host anemone preference, usually being associated with Heteractis magnifica. Fortunately, the three species exhibit allopatric distributions and are therefore easily separated on the basis of geographic range.

[FIGURE 5 OMITTED]

Our genetic results (Fig. 5) indicate that A. pacificus and A. sandaracinos are closely related, forming a moderately supported clade that is well differentiated from A. akallopisos. The control region, which was utilised for the analysis, is known to be a quickly evolving gene (Bowen et al. 2006) and therefore is ideal for fine resolution phylogenetics and population genetic studies (Drew et al. 2010). The geographic, morphological, and meristic differences, in combination with the reciprocal monophyly at the mtDNA control region, provide multiple lines of evidence supporting the validity of A. pacificus.

The three species generally differ from other anemonefishes in having an overall pale colouration, lack of white bars on the head and body, and a whitish mid-dorsal stripe on the forehead region that extends along the base of the dorsal fin. In A. sandaracinos the forehead stripe is well contrasted and extends onto the upper lip (Fig. 4), whereas it is not as vivid in the other two species and fails to reach the upper lip. Moreover, the ground colour of A. sandaracinos is more or less uniformly orange in contrast to the other species, which are pinkish brown dorsally and have a strong yellow cast on the ventral half of the body.

Although our genetic evidence indicates a closer relationship to A. sandaracinos, the new species is nearly identical in appearance to A. akallopisos. The nearest populations (Bali and Wallis Island) of these two species are separated by approximately 7,000 km. We have no doubt that the huge distributional gap is genuine and not a collection artifact. Anemonefishes are conspicous, often photographed elements of the reef fish fauna, and their distribution has been well documented in both popular and scientific media. The classification and biology of these fishes was the subject of the first author's doctoral thesis and since the publication of this work (Allen 1972) he has placed special emphasis on the details of their distribution. The known range of A. pacificus encompasses a sea surface area of approximately 870,000 [km.sup.2]. This limited, relatively localised distribution is typical of many species of Amphiprion. Ten of the 29 known species have ranges that occupy similar or smaller areas. Moreover, the Fiji-Tonga region in particular, is recognised as an important regional hotspot of endemism with at least 30 reef fish endemics represented (Allen 2008; Drew et al. 2008).

There appear to be modal differences in the number of anal rays and pectoral rays between A. pacificus (usually 13 and 17 respectively) and A. sandaracinos (usually 12 and 18), although additional specimens of the former species are required to confirm this discrepency. Similarly, there is an apparent modal difference in the total number of gill rakers on the first branchial arch between A. pacificus (usually 17) and A. akallopisos (18-19). These differences are summarised in Tables II and III.

Distribution and habitat: Amphiprion pacificus is reliably known only from Fiji, Tonga, Samoa and Wallis Island. It does not appear to be common at any of these locations. It is generally commensal with the anemone Heteractis magnificus (Quoy & Gaimard, 1833) at depths between about 4-10 m.

Etymology: This species is named Amphiprion pacificus with reference to the Pacific Ocean distribution.

ACKNOWLEDGEMENTS

We are especially grateful to Jeff Williams, who collected the holotype and provided a colour photograph of the freshly collected specimen. Scott Michael of Lincoln, Nebraska provided photographs and three paratypes of the new species, which he received from aquarium fish collectors at Tonga. Dive guide Josh Jensen sent us valuable photographs of the new species, confirming its presence at Fiji. This work was supported by the National Science Foundation under a Postdoctoral Fellowship in bioinformatics (2008) to the second author with additional support from the John D. and Catherine T. MacArthur Foundation for the Encyclopedia of Life project. This work is a contribution of the Marine Management Area Science Program of Conservation International, funded by the Gordon and Betty Moore Foundation. The molecular analysis was carried out in the Field Museum's Pritzker Laboratory for Molecular Systematics and Evolution operated with support from the Pritzker Foundation.

Received 27 April 2010 - Accepted 27 June 2010

ERRATA

Last, P. R., White, W. T. & Puckridge, M. (2010). Neotrygon ningalooensis n. sp. (Myliobatoidei: Dasyatidae), a new maskray from Australia. aqua, International Journal of Ichthyology, 16(2): 37-50.

Unfortunately I made an error in 2 of the captions (Figs 2 and 7) by having 'n. sp.' after Neotrygon leylandi which was described by Last 1987 and is a nominal species. Not sure whether this needs an errata.

REFERENCES

ALLEN, G. R. 1972. The Anemonefishes, their Classification and Biology. T. F. H. Publications, Neptune City, New Jersey, 288 pp.

ALLEN, G. R. 1980. Anemonefishes of the World. Aquarium Systems, Mentor, Ohio, 104 pp.

ALLEN, G.R. 2008. Conservation hotspots of biodiversity and endemism for Indo-Pacific coral reef fishes. Aquatic Conservation: Marine and Freshwater Ecosystems: 18: 541-556.

ALLEN, G. R., DREW, J. & KAUFMAN, L. 2008. Amphiprion barberi, a new species of anemonefish (Pomacentridae) from Fiji, Tonga, and Samoa. aqua, International Journal of Ichthyology 14 (3): 105-114.

BOWEN, B. W., MUSS, A., ROCHA, L. A. & GRANT, W. S. 2006. Shallow mtDNA coalescence in Atlantic pygmy angelfishes (genus Centropyge) indicates a recent invasion from the Indian Ocean. Journal of Heredity 97: 11-12.

COOPER, J. W., SMITH, L. L. & WESTNEAT, M.W. 2009. Exploring the radiation of a diverse reef fish family: Phylogenetics of the damselfishes (Pomacentridae), with new classifications based on molecular analyses of all genera. Molecular Phylogenetics and Evolution 52: 1-16.

DREW, J., ALLEN, G. R., KAUFMAN, L. & BARBER, P. H. 2008. Endemism and regional color and genetic differences in five putatively cosmopolitan reef fishes. Conservation Biology 22 (4): 965-975.

DREW, J. A., ALLEN, G. R. & ERDMANN, M. V. 2010. Congruence between mitochondrial genes and color morphs in a coral reef fish: population variability in the Indo-Pacific damselfish Chrysiptera rex (Snyder, 1909). Coral Reefs. Published online: DOI: 10.1007/s00338-010-0586-5.

FAUTIN, D. G. & ALLEN, G. R. 1992. Field guide to anemonefishes and their host sea anemones, Western Australian Museum, Perth, 160 pp.

LEE, W. J., HOWELL, W. H. & KOCHER, T. D. 1995. Structure and evolution of teleost mitochondrial control regions. Journal of Molecular Evolution 41: 54-66.

RONQUIST, F. & HUELSENBECK, J. P. 2003. MrBayes 3: Bayesian phylogenetic inference under mixed models. Bioinformatics 19 (12): 1572-1574.

WALSH, P. S., METZGER, D. A. & HIGUCHI, R. 1991. Chelex-100 as a medium for simple extraction of DNA for PCR based typing from forensic material. Biotechniques 10: 506-513.

Gerald R. Allen (1), Joshua Drew (2) and Douglas Fenner (3)

(1) Department of Aquatic Zoology, Western Australian Museum, Locked Bag 49, Welshpool DC, Perth, Western Australia 6986

(2) Biodiversity Synthesis Center, Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, Illinois 60605, USA

(3) Department of Marine and Wildlife Resources, Pago Pago, American Samoa 96799
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Author:Allen, Gerald R.; Drew, Joshua; Fenner, Douglas
Publication:aqua: International Journal of Ichthyology
Article Type:Report
Geographic Code:8FIJI
Date:Jul 15, 2010
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