A new species of damselfish (Pomacentrus: Pomacentridae) from Brunei and the Philippines

Transcription

1 aqua, International Journal of Ichthyology A new species of damselfish (Pomacentrus: Pomacentridae) from Brunei and the Philippines Gerald R. Allen 1*, Mark V. Erdmann 2 and Vincent V. Hiloman 3 1) Western Australian Museum, Locked Bag 49, Welshpool DC, Perth, Western Australia tropical_reef@bigpond.com 2) Conservation International, Jl. Dr. Muwardi No. 17, Renon, Denpasar Indonesia 3) Animal Biology Division, Institute of Biological Sciences, University of the Philippines Los Baños, College, Laguna 4031, Philippines Received: 02 July 2010 Accepted: 01 December 2010 Abstract Pomacentrus cheraphilus n. sp. is described from 19 specimens, mm SL, collected at Brunei and northern Palawan, Philippines. It is distinguished from most similar species in the western Pacific by a combination of characters that include XIII dorsal spines, soft dorsal rays, soft anal rays, pectoral rays, tubed lateral-line scales, total gill rakers on the first branchial arch, a yellow juvenile phase with blue stripes on the upper head and adjacent anterodorsal portion of the body, and light grey to dark greyish brown adult phase with a dark-edged greenish spot just below lateral line origin. The new species inhabits silty reefs around coral and rock outcrops at depths of m. Zusammenfassung Pomacentrus cheraphilus n. sp. wird anhand von 19 Exemplaren mit 48,7 bis 61,0 mm SL beschrieben, die bei Brunei und Nord-Palawan, Philippinen, gesammelt wurden. Von den sehr ähnlichen Arten des westlichen Pazifiks unterscheidet sich die neue Art durch eine Kombination von be - stimmten Merkmalen dazu gehören: XIII Rückenflossenstacheln, weiche Rückenflossenstrahlen, weiche Afterflossenstrahlen, Brustflossenstrahlen, röhrenförmige Seitenlinien-Schuppen, vollständige Kiemenreusen auf dem ersten Kiemenbogen, eine gelbe Jugendphase mit blauen Streifen auf dem Kopf oben und dem sich anschließenden vorderen Rückenteil des Rumpfes sowie ein Erwachsenenstadium mit einer hellgrauen bis dunkel gräulich braunen Grundfarbe und einem dunkel umrandeten grünlichen Fleck genau unterhalb des Beginns der Seitenlinie. Die neue Art bewohnt schluffige Riffe um Korallen- und Felserhebungen herum in einer Tiefe von 10 bis 18 Metern. Résumé Pomacentrus cheraphilus n. sp. est décrit sur base de 19 spécimens, de 48,7 à 61,0 mm de LS, collectés à Brunei et au nord de Palawan, Philippines. Elle se distingue de la plupart des espèces similaires par une combinaison de cara - ctéristiques qui comprennent XIII épines dorsales, rayons mous à la dorsale, rayons mous à l anale, rayons pectoraux, écailles canaliculées de la ligne latérale, un total de branchiospines sur le premier arc branchial, une phase juvéniles jaune avec des lignes bleues sur le haut de la tête et la portion adjacente antérodorsale du corps et une phase adulte grise à gris foncé avec une tache verdâtre à bord sombre juste sous la naissance de la ligne latérale. La nouvelle espèce peuple des récifs limoneux autour d affleurements de coraux ou de roches à des profondeurs de m. Sommario Pomacentrus cheraphilus n. sp. è descritta sulla base di 19 esemplari di mm SL raccolti a Brunei e Palawan settentrionale, Filippine. Si distingue dalle specie più simili del Pacifico occidentale per una combinazione di caratteri che includono: XIII spine dorsali, raggi dorsali molli, raggi anali molli, raggi pettorali, scaglie della linea laterale con tubicino, rastrelli sul primo arco branchiale, una fase giovanile a livrea gialla con strie blu sulla parte superiore del capo e sull adiacente porzione anterodorsale del corpo e, infine, una fase adulta caratterizzata da una colorazione che va dal grigio chiaro al marronegrigiastro scuro con una macchia verdastra orlata di scuro proprio sotto l origine della linea laterale. La nuova specie abita zone limose di barriera intorno affioramenti corallini e rocciosi a profondità di metri. INTRODUCTION Damselfishes of the genus Pomacentrus are common inhabitants of coral reefs throughout the Indo-west and central Pacific Ocean. Allen (1991) 35 aqua vol. 17 no January 2011

2 A new species of damselfish (Pomacentrus: Pomacentridae) from Brunei and the Philippines recognized 54 species, but since then an additional 18 species have been described (Allen 1992, 1993, 1995, 1999, 2002, 2004; Allen & Erdmann 2009; Allen & Randall 2004, 2005; Allen & Wright 2003; Randall 2002). It is the second largest genus in this major reef-fish family that globally contains approximately 360 species, surpassed only by Chromis with 86 species. The majority (about 68%) of Pomacentrus are primarily distributed in the western and central Pacific region, with lesser representation in the Indian Ocean. The genus is particularly well represented in the diverse Indo-Malayan region where approximately 50 species are known to occur. The present paper describes a new species of Pomacentrus that was first noticed in 2007 during a conservation survey in Bacuit Bay, near El Nido near the northern tip of Palawan Island, Philippines. It was immediately recognized as a new taxon by the first author, who has extensive experience with the taxonomy of pomacentrid fishes. Ten specimens were eventually collected the following year as well as nine additional specimens from the northwestern coast of Borneo at Brunei. 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; 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; and 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 and meristic data are provided in Tables I and II respectively. Type specimens are deposited at the Museum of Natural History, University of the Philippines Los Baños (UPLB), National Museum of Natural History, Washington, D.C. (USNM) and Western Australian Museum, Perth (WAM). Pomacentrus cheraphilus n. sp. (Figs 1-3; Tables I-II) Holotype: WAM P , male, 55.5 mm SL, East Brunei Patches, N, E, Brunei, m, spear, G. R. Allen, 20 October Paratypes: UPLB Z-NS , 9 specimens, mm SL, Dibuluan Island, N, E, Bacuit Bay, El Nido, Palawan Province, Philippines, m, spear, G. R. Allen, 12 June 2008; USNM , 5 specimens, mm SL, collected with holotype; WAM P , 4 specimens, mm SL, collected with holotype. Diagnosis: Dorsal rays XIII,13-14; anal rays II,13-15; pectoral rays 17-18; tubed lateral-line scales 17-19; gill rakers (total 19-21); body depth in SL; colour in life generally light grey to dark greyish brown, including median fins, with dark-edged greenish spot just below lateral-line origin; small juveniles bright yellow with diagonal blue bands on upper head and anterodorsal portion of body, and prominent ocellus on middle of dorsal fin. aqua vol. 17 no January

3 Gerald R. Allen, Mark V. Erdmann and Vincent V. Hiloman Description: Dorsal rays XIII,14 (XIII,13-14); anal rays II,14 (II, 13-15); all dorsal and anal soft rays branched, the last to base; pectoral rays 17 (17-18), lower ray and uppermost pair unbranched; pelvic rays I,5; principal caudal rays 15, median 13 branched; upper and lower procurrent caudal rays 5, posterior pair segmented; scales in longitudinal series 28 (27-28); tubed lateral-line scales 18 (17-19); posterior midlateral scales with pore or deep pit (in continuous series) 7 (7-8); 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 9; gill rakers ( ), total rakers 19-21; pseudobranch filaments 14 (12-16). Body ovate, depth 1.9 ( ) in SL, and compressed, width 2.5 ( ) in body depth; HL 3.1 ( ) in SL; dorsal profile of head evenly rounded from dorsal-fin origin to snout; snout shorter than orbit, its length 3.6 ( ) in HL; orbit diameter 3.1 ( ) in HL; interorbital space convex, its width 4.1 ( ) in HL; caudal-peduncle depth 2.0 ( ) in HL; caudalpeduncle length 2.6 ( ) in HL. Mouth terminal, small and oblique, forming angle of about to horizontal axis of head and body; maxilla reaching vertical about even with anterior edge of pupil, upper jaw length 3.5 Fig. 1. Underwater photograph of Pomacentrus cheraphilus, adult, approximately 60 mm SL, Bacuit Bay, northern Palawan, Philippines. Photo by G. R. Allen. 37 ( ) 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 (32-38) in each jaw (excluding buttress teeth). Tongue triangular with rounded tip, set far back in mouth. Gill rakers long and slender, longest on lower limb near angle, about two-thirds to 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 flat spine, tip obtuse, barely projecting from beneath large scale; rear margin of preopercle with 19 (18-23) serrae; preorbital with single (occasionally double in paratypes) serra separated by notch from suborbital series; lower edge of suborbital with 7 (2-6) serrae; rear edge of posterior circumorbitals with (1-6) minute serrae. Scales finely ctenoid; head scaled except for lips, tip of snout, preorbital and suborbital; scaly sheath at base of dorsal and anal fins, averaging about two-thirds pupil width at base of dorsal fin and about the same width at base of anterior part of anal fin, gradually tapering in width posteriorly; column of scales on each membrane of dorsal and anal fins, narrowing distally, those on spinous poraqua vol. 17 no January 2011

4 A new species of damselfish (Pomacentrus: Pomacentridae) from Brunei and the Philippines Fig. 2. Underwater photographs showing juvenile and subadult stages of Pomacentrus cheraphilus (all taken at Brunei, except A at Bacuit Bay, Palawan, Philippines): A, approximately 18 mm SL; B, approximately 25 mm SL; C, approximately 35 mm SL; and D, approximately 45 mm SL. Photos by G. R. Allen. tion 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; 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, its length also about half that of pelvic spine or slightly longer. Origin of dorsal fin over second or third tubed lateral-line scale, predorsal distance 2.9 ( ) 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 3.7 ( ) in HL; second dorsal spine 2.8 ( ) in HL; seventh dorsal spine 2.0 ( ) in HL; last dorsal spine 1.6 ( ) in HL; membranes of spinous portion of dorsal fin incised near spine tips; seventh dorsal soft ray longest, 1.2 ( ) in HL; first anal spine 4.0 ( ) in HL; second anal spine 1.9 ( ) in HL; longest (ninth) anal soft ray 1.3 ( ) in HL; caudal fin slightly forked with angular lobes, its length 3.4 ( ) in SL; fourth pectoral ray longest, 3.3 ( ) in SL; pelvic spine 1.8 ( ) in length of pelvic fin; first soft ray of pelvic fin forming filamentous tip (damaged in some specimens), pelvic fin length 2.8 ( ) in SL. Colour in life of adult (from underwater photograph, Fig. 1): variable ranging from overall pale grey to dark greyish brown, with darker scale margins and frequently with 2-3 small blue spots or blue streak on each scale; prominent blackedged green spot (about half pupil size) on upper rear edge of operculum; median fins generally same colour as body; dorsal fin with dull bluish submarginal stripe and narrow blue to whitish outer margin; anal fin with pair of dull bluish stripes across middle portion of fin and narrow bright blue outer margin; outer third of caudal fin frequently translucent whitish to bluish; pectoral and pelvic fins translucent pale greyish, anterior edge of pelvic fin narrowly blue. Colour in life of juveniles and s u b a d u l t (from underwater photographs, Fig. 2): smallest specimens (< about 20 mm SL, Fig. 2A) bright yellow with pair of blue bands on upper part of head, converging below spinous part of dorsal fin and connecting with large blue-edged black aqua vol. 17 no January

5 Gerald R. Allen, Mark V. Erdmann and Vincent V. Hiloman Table I. Proportional measurements of selected type specimens of Pomacentrus cheraphilus as percentage of the standard length. Holotype Paratype Paratype Paratype Paratype Paratype Paratype Paratype WAM UPLB UPLB WAM UPLB UPLB UPLB UPLB P P Standard length (mm) Body depth Body width Head length Snout length Orbit diameter Interorbital width Depth of caudal peduncle Length of caudal peduncle Upper jaw length Predorsal distance Preanal distance Prepelvic distance Length of dorsal fin base Length of anal fin base Pectoral fin length Pelvic fin length Pelvic fin spine length st dorsal spine th dorsal spine Last dorsal spine Longest soft dorsal ray st anal spine nd anal spine Longest soft anal ray Caudal fin length Caudal concavity Table II. Meristic data for Pomacentrus cheraphilus. Dorsal rays Anal rays Pectoral rays LL scales Upper limb GR Lower limb GR Total gill rakers spot on middle of dorsal fin, similar blue band from lower rear edge of eye to just below dorsal-fin spot and small blue spot on upper edge of caudal peduncle. Larger juvenile (about mm SL, Fig. 2B) bluish grey with bright blue scale margins on upper part of head and body above imaginary line connecting lower margin of eye and upper edge of caudal peduncle and yellow below this line; pair of bright blue bands on top of head as in small juveniles, but upper extending to dorsal fin origin and lower reaching about half this distance; also shorter blue bands and narrow lines on side of snout, behind eye and on suborbital; dorsal fin bluish grey with blue flecks, narrow blue margin and large blue-edged black spot on middle portion of fin. Large juvenile (about mm SL, Fig. 2C) mainly bluish grey with bright blue scale margins and yellowish abdominal region; bright blue bands and other markings similar to those of mm SL individual. Subadult (about mm SL, 39 aqua vol. 17 no January 2011

6 A new species of damselfish (Pomacentrus: Pomacentridae) from Brunei and the Philippines Fig. 3. Pomacentrus cheraphilus, holotype, male, 55.5 mm SL, Brunei. Photo by G. R. Allen. Fig. 4. Map of South China Sea region showing distributional range of Pomacentrus cheraphilus. aqua vol. 17 no January

7 Gerald R. Allen, Mark V. Erdmann and Vincent V. Hiloman Fig. 2D) greyish with blues streak or 2-3 blue dots on each scale; remnants of bright blue bands on snout and forehead and numerous blue spots and narrow blue lines on side of head; dark-edged green spot on upper rear edge of operculum; remnant of ocellus on rear portion of dorsal fin; narrow blue to white stripe on dorsal and anal fin margins, as well as submarginal blue stripes. Colour in alcohol (Fig. 3): holotype generally brown with darker scale margins; small blackish spot on upper rear edge of operculum; median fins brown to dark grey; dorsal fin with broad pale grey submarginal stripe; anal fin with pair of pale grey stripes across middle portion; pelvic and pectoral fins tannish to pale grey. The smallest paratype (48.7 mm SL) has a faint ocellus, a remnant of the typical juvenile marking, in the middle of the posterior dorsal fin between the eighth and eleventh soft rays. The Brunei paratypes are similar to the holotype, whereas those from Palawan are generally paler (tan to pale grey). Comparisons: The new species generally resembles several other nondescript, mainly dark brown or greyish brown Pomacentrus from the western Pacific including P. adelus Allen, 1991 (widespread Indo-Malayan region), P. armillatus Allen, 1993 (Borneo and Philippines), P. bintanensis Allen, 1999 (Bintan Island, Indonesia), P. burroughi Fowler, 1918 (widespread Indo-Malayan region), P. cuneatus Allen, 1991 (widespread Indo-Malayan region), P. fakfakensis Allen & Erdmann, 2009 (Fakfak Peninsula, West Papua, Indonesia), P. komodensis Allen, 1999 (Komodo Island, Indonesia), P. littoralis Cuvier, 1830 (widespread western Pacific), P. melanochir Bleeker, 1877 (eastern Indonesia), P. milleri Taylor, 1964 (western and northern Australia), P. opisthostigma Fowler, 1918 (widespread Indo-Malayan region), P. tripunctatus Cuvier, 1830 (widespread western Pacific and eastern Indian Ocean), and P. wardi Whitley, It differs from P. armillatus, P. fakfakensis, P. milleri and P. opisthostigma in having 13 instead of 14 dorsal spines (see Allen 1991, 1993, 1999 and Allen & Erdman 2009 for diagnoses of these and other Pomacentrus), although P. milleri occasionally has 13 spines. It differs from the remaining 13-spined species by a combination of features that include soft dorsal rays, soft anal rays, pectoral rays, tubed lateral-line scales, total gill rakers on the first branchial arch, a yellow juvenile phase with blue stripes on the upper head and adjacent anterodorsal portion of the body and light grey to dark greyish brown adult phase with a dark-edged greenish spot just below lateral-line origin. Pomacentrus littoralis possesses a similar greenish spot above the lateral-line origin, but differs in having scales on the preorbital (lacrimal) and lacks the bright yellow juvenile phase. Although both Pomacentrus adelus and P. wardi have similar yellow juvenile stages, P. adelus differs from P. cheraphilus in having a higher number (22-24) of total gill rakers on the first arch, and P. wardi generally has a higher number (15-16) of soft dorsal rays. Pomacentrus burroughi has more (15-16) soft dorsal rays, fewer lateral-line scales (14-17), and more (24-25) total gill rakers on the first arch. Pomacentrus komodoensis differs in having scales on the rear portion of the suborbital series and usually has 19 pectoral rays. Pomacentrus melanochir has a more slender body (depth in SL versus , rarely 2.2), smooth suborbital margin and very weak serrations on the preopercular margin. The new species differs from P. cuneatus in having a higher modal count of lateral-lines scales (usually 18 versus 16-17) and predominately yellow colouration in small juveniles (versus mainly blue grey). Finally, P. tripunctatus and P. bintanensis have similar morphological and meristic attributes, but differ noticeably in colour pattern and ecology. Both species lack a yellow juvenile stage and are restricted to shoreline reefs in extremely shallow depths, usually less than 3 metres and frequently less than 2 metres. The adult and juvenile stages of P. tripunctatus are characterised by a large black saddle dorsally on the caudal peduncle, whereas P. bitanensis is a uniformly dark fish without distinctive markings in both adults and juveniles. Distribution and ecology: The new species is currently known from Brunei and northern Palawan, Philippines (Fig. 4). It was relatively common at both locations on silty reefs around coral and rock outcrops at depths of m. Etymology: The new species is named cheraphilus (Greek: silt-lover) with reference to its predilection for silty habitats. ACKNOWLEDGEMENTS We thank the Brunei Ministry of Industry and Primary Resources, especially the Department of Fisheries, for hosting research expeditions in 2008 and Special thanks in this regard are due to Hajah Hasnah binti Ibrahim, Director of Fisheries and Dayang Ranimah Hu Abdul Wahab, Head of Marine Fisheries Development and Management 41 aqua vol. 17 no January 2011

8 A new species of damselfish (Pomacentrus: Pomacentridae) from Brunei and the Philippines Division. We also express gratitude to their many staff members for providing excellent logistic support for boating and diving activities during our visits. Likewise, we are very grateful to Leigh Talmage- Perez of the Asian Conservation Company and El Nido Resorts for their wonderful support during our (GRA and MVE) visits to the El Nido region during 2007, 2008, and The fish surveys during these visits were made possible by the cooperation of several key organisations including the Protected Area Management Board of the El Nido- Taytay Managed Resource Area, the Palawan Council for Sustainable Development, the Department of Environment and Natural Resources, the Municipal and Barangay Goverments of El Nido, Ten Knots Development Corporation, and the El Nido Foundation. 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. Records of the Western Australian Museum 15 (4): ALLEN, G. R Two new species of damselfishes (Pomacentrus), with comments on the validity of two additional pomacentrid fishes. Revue Française d Aquariologie et Herpetologie 20 (1): ALLEN, G. R Two new species of damselfishes (Pomacentridae) from Indonesian seas. Revue Française d Aquariologie et Herpetologie 21 (3-4): ALLEN, G. R Three new species of damselfishes (Pomacentridae) from Indonesia and eastern Papua New Guinea. Revue Française d Aquariologie et Herpetologie 25 (3-4): ALLEN, G. R Descriptions of two new species of damselfishes (Pomacentridae: Pomacentrus) from Madagascar. aqua, Journal of 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. & ERDMANN, M.V A new species of damselfish (Pomacentridae) from western New Guinea. Records of the Western Australian Museum 25: ALLEN, G. R. & RANDALL, J. E Two new species of damselfishes (Pomacentridae) from Micronesia. aqua, Journal of Ichthyology and Aquatic Biology 9 (2): ALLEN, G. R. & RANDALL, J. E A new species of damselfish (Pomacentrus: Pomacentridae) from Fiji. aqua, Journal of Ichthyology and Aquatic Biology 10 (3): ALLEN, G. R. & WRIGHT J. E Description of a new species of damselfish (Pomacentridae: Pomacentrus) from Rodrigues Island, Indian Ocean. aqua, Journal of Ichthyology and Aquatic Biology 7 (4): BLEEKER, P Description de quelques espèces inédites de Pomacentroïdes de l Inde archipélagique. Verslagen en Mededeelingen der Koninklijke Akademie van Wetenschappen. Afdeeling Natuurkunde (Series 2) 10: CUVIER, G. & VALENCIENNES. A Histoire naturelle des poissons. Tome cinquième. Livre cinquième. Des Scié - noïdes. Volume 5: i-xxviii pp., Pls FOWLER, H. W New and little-known fishes from the Philippine Islands. Proceedings of the Academy of Natural Sciences of Philadelphia 70: RANDALL, J. E Two new damselfishes of the genus Pomacentrus from the south-west Pacific. aqua, Journal of Ichthyology and Aquatic Biology 5 (4): TAYLOR, W. R Fishes of Arnhem Land. Records of the American-Australian scientific expedition to Arnhem Land. Vol. 4, Zoology edited by R. L. Specht. Fishes of Arnhem Land. Records of the American-Australian scientific expedition to Arnhem Land 4: WHITLEY, G. P Studies in ichthyology. No. 1. Records of the Australian Museum 15 (5): aqua vol. 17 no January