A new species of wrasse (Labridae: Choerodon) from the tropical western Pacific

aqua, Journal of Ichthyology and Aquatic Biology A new species of wrasse (Labridae: Choerodon) from the tropical western Pacific 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 96817-2704, U.S.A. Accepted: 08.04.2002 Keywords Taxonomy, marine fishes, Choerodon, new species, Labridae, Western Pacific Abstract Choerodon gomoni is described from six specimens, 86.1-103.9 mm SL, from the Chesterfield Bank, Coral Sea and the Banggai Islands, Indonesia. It belongs to the Peaolopesia complex of species that includes C. sugillatum (northern Australia), C. margaritiferus (Philippines), C. japonicus (Taiwan and Japan), C. gymnogenys (East Africa), and another undescribed East African species. The members of this complex are morphologically similar and best separated on the basis of colour pattern. Choerodon gomoni is distinguished by its male and female colour patterns. The male pattern, which includes a large reddish spot on the middle of the back and a pale yellow lateral stripe, is particularly distinctive. Zusammenfassung Chorodon gomoni wird an hand von sechs Exemplaren (86,1 bis 103,9 mm SL) von der Chesterfield Bank im Korallen Meer und den Banggai Inseln (Indonesien) beschrieben. Sie gehört zum Peaolopesia - Artenkreis, der C. sugillatom (nördliches Australien), C. margaritiferus (Philippinen), C. japonicus (Taiwan und Japan), C. gymnogenys (Ostafrika) sowie eine noch unbeschriebene, ostafrikanische Art umfasst. Die Spezies in diesem Artenkreis sind morphologisch einander ähnlich, und am leichtesten an hand ihrer Farbmuster zu unterscheiden. Choerodon gomoni ist durch unterschiedlichen Farbmuster der Männchen und Weibchen charakterisiert. Das Muster des Männchens - mit einem großen schwarzen Flecken in der Rückenmitte und einen blassgelben Seitenstreifen - ist ganz besonders auffällig. Résumé Choerodon gomoni est décrit à partir de six spécimens, 86,1-103,9 mm LS, du Chesterfield Bank, de la Mer de Corail et des îles Banggai, Indonésie. Il appartient au "complexe" Peaolopesia qui comprend C. sugillatum (nord de l'australie), C. margaritiferus (Philippines), C. japonicus (Taiwan et Japon), C. gymnogenys (est de l'afrique) et une autre espèce non décrite de l'afrique orientale. Les espèces de ce complexe sont morphologiquement semblables et se distinguent le mieux sur base de leur patron de coloration. Choerodon gomoni se distingue par ses patrons de coloration mâle et femelle. Le patron mâle, qui comprend une grande tache rougeâtre au milieu du dos et une ligne latérale jaune pâle, est particulièrement distinctif. Sommario La nuova specie Choerodon gomoni viene descritta sulla base di sei esemplari, 86.1-103.9 mm SL, raccolti nel Chesterfield Bank, Mar dei Coralli e nelle Isole Banggai, Indonesia. Essa appartiene al complesso di specie Peaolopesia, che comprende C. sugillatum (Australia settentrionale), C. margaritiferus (Filippine), C. japonicus (Taiwan e Giappone), C. gymnogenys (Africa orientale) e un altra specie dell Africa orientale ma non ancora descritta. I membri di questo complesso di specie sono molto simili morfologicamente e possono essere distinti tra loro quasi esclusivamente sulla base della livrea. Choerodon gomoni si differenzia per la livrea sia del maschio sia della femmina. Quella del maschio, che si caratterizza per la presenza di una larga macchia rossastra sulla parte centrale del dorso e per una stria laterale giallo pallida, è inconfondibile. Introduction The labrid genus Choerodon Bleeker occurs on reefs and adjacent sand-rubble bottoms of the tropical Indo-Pacific. The genus contains approximately 22 valid species (Parenti and Randall, 2000). Australia, with a rich mixture of endemics and wide-ranging forms, is home to 16 species, more than any other region. Members of the genus range in maximum size from about 12 to 90 cm. The head is relatively deep for the family, and is characterized by a broad cheek and blunt, rounded snout. Although the various species are primarily solitary in habit, pairs or larger groups are sometimes encountered. 109

A new species of wrasse (Labridae: Choerodon) from the tropical western Pacific The present paper describes a new species encountered by G. R. Allen while participating in a Conservation International coral reef survey at the Banggai Islands, off central eastern Sulawesi in 1998. Subsequent examination of the collection at the Bishop Museum in Honolulu revealed several additional specimens obtained by trawl at the Chesterfield Bank, Coral Sea in 1988. The methods used for counts and measurements are as follows: pectoral fin-ray counts include the rudimentary upper ray; gill-raker counts pertain to the first gill arch and include rudiments. Standard length (SL) is the horizontal straight-line distance from the front of the upper lip to the base of the caudal fin; head length is taken from the front of the upper lip to the posterior end of the opercular membrane; body depth is the maximum depth measured from the base of the dorsal spines; eye diameter is the greatest fleshy diameter of the orbit, and interorbital width is the least bony width; snout length is measured from the front of the upper lip to the fleshy anterior edge of the orbit; caudal-peduncle depth is the least depth, and caudal-peduncle length is the horizontal distance from the rear base of the anal fin to the caudal-fin base; lengths of spines and soft rays of fins are measured in a straight line from their extreme bases to their distal ends. Counts and measurements appearing in parentheses pertain to paratypes different from the holotype. Type specimens are deposited in the Australian Museum, Sydney (AMS), Bishop Museum, Honolulu (BPBM), Muséum National d Histoire Naturelle, Paris (MNHN), National Museum of Natural History, Smithsonian Institution, Washington, D. C. (USNM), and Western Australian Museum, Perth (WAM). Choerodon gomoni n. sp. Figs. 1-2; Table I Holotype: BPBM 33850, male, 101.0 mm SL, Chesterfield Bank, Coral Sea (approximately 20 45 00 S, 158 35 04 E), beam trawl in 82 m, R.V. Alis station 16, 22 August 1988. Paratypes: (all from Chesterfield Bank, Coral Sea) AMS I.41000-00l, male, 106.0 mm SL, approximately 21 05 00 S, 158 57 06 E, beam trawl in 72 m, R.V. Alis station 32, 24 August 1988; BPBM 33840, female, 88.5 mm SL, approximately 20( 45 00 S, 158 50 06 E, beam trawl in 75 m, R.V. Alis station 10, 22 August 1988; MNHN 2001-2358, female, 92.5 mm SL, approximately 21 05 00 S, 158 57 06 E, beam trawl in 72 m, R.V. Alis station 32, 24 August 1988; USNM 366799, male, 97.0 mm SL, approximately 20 45 00 S, 158 50 06 E, beam trawl in 75 m, R.V. Alis station 10, 22 August 1988; WAM P.31498-003, female, 87.5 mm SL, northwest side of Bangang Island, Banggai Islands, Indonesia (1 41.12 S, 123 27.50 E), spear in 30 m, G. R. Allen, 4 November 1998. Diagnosis Dorsal rays XII,7 or 8; anal rays III,9 or 10; pectoral rays 14 (rarely 15); lateral-line scales 27 (plus pair of tubed scales on caudal-fin base); median predorsal scales 6-7; transverse scale rows on rear part of cheek 2-3; gill rakers 5-7 + 9 or 10 (total rakers on first arch 15-17); body depth 3.4-4.0 in SL; coloration generally pale, male with eye-sized (or larger) red-brown spot on back below middle of dorsal fin. Fig. 1. Choerodon gomoni, male holotype (BPBM 33850), 101.0 mm SL, Chesterfield Islands, Coral Sea. Photo by J. E. Randall. 110

Gerald R. Allen and John E. Randall Description Dorsal fin rays XII,8 (7 or 8); anal fin rays III,9 (9 or 10); all dorsal and anal soft rays branched; last dorsal and anal rays branched to base; pectoral rays 14 (15 in one paratype), the upper and lowermost unbranched; pelvic fin rays I,5; principal caudal rays 14, upper and lowermost unbranched; upper and lower procurrent caudal rays 4-5; lateral line continuous, consisting of 27 tubed scales plus a pair of tubed scales on caudal-fin base, each scale with central tube and smaller branched tube dorsally; scales above lateral line to origin of dorsal fin 2 1/2; scales below lateral line to origin of anal fin 7 1/2; median predorsal scales 7 (6-7); median prepelvic scales 7 (7-8); rows of scales on rear portion of cheek 2-3; circumpeduncular scales 14; gill rakers on first branchial arch 7 + 9 (5-7 + 9-10), total rakers on first arch 16 (15-17); branchiostegal rays 5; vertebrae 9 + 16. Body depth 3.4 (3.6-4.0) in SL; head length 2.5 (2.5-2.9) in SL; snout length 3.3 (3.4-4.2) in head length; eye diameter 5.2 (4.5-4.9) in head length; width of bony interorbital 4.9 (4.7-5.4) in head length; depth of caudal peduncle 4.1 (3.6-4.1) in head length; length of caudal peduncle 2.6 (2.2-2.7) in head length. Mouth small, terminal, and slightly oblique, the maxilla nearly reaching the vertical at front edge of orbit; front of upper jaw with two pairs of greatly enlarged canines of about equal size, the anterior pair (one tooth missing in holotype) projecting forward and curved ventrally; posterior pair curved ventrally; 1-2 smaller, recurved canines at posterior part of jaw, and several small conical teeth sometimes present between anterior canines; remainder of upper jaw with thin, sharp bony plate or ridge. Lower jaw with two pairs of prominent anterior canines, the inner pair slightly smaller than strongly curved (laterally) outer pair and directed anterolaterally; a thin, bony plate or ridge behind canines with about 10-12 small, conical teeth on each side of the jaw. Nostrils small, on a line between top of eye and tip of snout, anterior nostril at mid- point on this line and posterior nostril about mid way between anterior edge of eye and anterior nostril; posterior nostril ovate without a rim, about twice as large as anterior nostril; anterior nostril in a short membranous tube. circumorbital pores 30 pores along margin of preopercle 18, plus 8 in mandibular series; upper margin of preopercle with inconspicuous, blunt serrae (sometimes embedded); rounded corner of preopercle membranous. Scales cycloid; snout and interorbital scaleless; Table I. Proportional measurements of type specimens of Choerodon gomoni expressed as percentages of the standard length. Holotype Paratype Paratype Paratype Paratype Paratype BPBM AMS MNHN USNM BPBM WAM 33850 I.41000 2001 366799 33840 P.31498-00l -2358-00l male male female male female female Standard length (mm) 101.0 106.0 92.5 97.0 88.5 87.5 Body depth 29.2 26.1 24.9 27.5 25.4 26.5 Head length 40.3 39.0 35.3 40.0 36.1 34.9 Snout length 12.1 11.2 8.5 11.6 9.5 9.1 Eye diameter 7.7 8.4 7.9 8.1 7.5 7.1 Interorbital width 8.2 7.9 7.5 7.9 7.7 6.5 Depth of caudal peduncle 9.8 9.4 9.2 10.0 10.1 9.5 Length of caudal peduncle 15.7 14.7 13.2 15.0 13.5 15.8 Dorsal-fin base 50.5 48.1 48.1 47.5 51.6 50.4 Anal-fin base 24.4 22.1 21.6 21.9 25.1 22.1 1st dorsal spine 5.0 5.5 4.9 6.0 4.9 4.7 2nd dorsal spine 7.2 7.4 7.1 7.5 6.2 7.0 Last dorsal spine 8.1 8.0 8.3 8.8 8.6 7.7 Last soft dorsal ray 8.5 7.4 8.3 8.4 7.7 7.2 1st anal spine 4.2 4.3 3.8 3.7 4.4 5.3 3rd anal spine 6.8 6.6 6.0 7.6 7.2 7.2 Last soft anal ray 8.2 8.1 7.3 7.7 7.8 5.9 Pectoral fin length 22.6 22.9 22.4 23.6 22.3 20.5 Pelvic fin length 21.4 20.6 19.0 22.2 18.9 17.7 Caudal fin length 19.7 18.3 19.3 19.2 19.7 18.1 111

A new species of wrasse (Labridae: Choerodon) from the tropical western Pacific pre-dorsal scales extending anteriorly to level between rear edge of eye and posterior margin of preopercle; head scales generally smaller than those on body; membranous edge of opercle and preopercle broadly scaleless; subopercle mainly naked, except single row of 6-7 small scales just below angle of preopercle; lower jaw naked; 2-3 transverse scale rows on rear part of cheek, otherwise cheek and suborbital region devoid of scales; basal sheath of dorsal and anal fins consisting of row of small (compared to adjacent body scales), pointed, elongate scales; tubes of lateral-line scales with a short dorsallydirected branch anteriorly; last two pored scales of lateral line (posterior to hypural plate) greatly enlarged, the terminal one extending to about middle of caudal fin; pectoral fins scaleless; 3-4 elongate scales adjacent to the outer edge of each pelvic fin, extending about two-thirds length of pelvic-fin spine; a pair of mid-ventral scales between bases of pelvic fins, the posterior scale elongate and pointed. Origin of dorsal fin above third lateral-line scale; first dorsal spine 8.1 (6.7-7.4) in head length; second dorsal spine 5.6 (5.0-5.9) in head; third to twelfth dorsal spines about equal in length, 5.0 (4.2-4.9) in head length; membranes of spinous portion of dorsal fin extending slightly above spine tips, posterior dorsal soft rays the longest, 4.8 (4.3-5.3) in head length; origin of anal fin about level with base of ninth dorsal spine; third anal spine longest, 5.9 (4.8-5.9) in head length; posterior anal soft rays longest, 4.9 (4.6-5.9) in head length; dorsal and anal fin rays falling well short of caudal-fin base; caudal fin truncate or with slightly longer rays in middle section, but also with slightly pointed upper and lower fin tips, longest rays 2.0 (1.8-2.1) in head length; second and third pectoral rays longest, 1.8 (1.6-1.7) in head length; origin of pelvic fins below lower edge of base of pectoral fins; pelvic fins short, usually just reaching level of anus in terminal males and falling short of this point in females, their length 1.9 (1.8-2.0) in head length. Colour of holotype when fresh: generally cream or slightly yellowish-white with pale mauve above lateral line and head slightly pinkish; iris yellow; a broad, white stripe from snout, passing below eye, and gradually fading toward middle of side on anterior body; large, diffuse, reddish-brown spot on back below base of ninth to eleventh dorsal-fin spines, its anterior edge bordered with white; a second, much smaller, fainter red spot above pectoral fin; also a faint yellow lateral stripe from upper pectoral base to upper portion of caudal fin base; fins mainly pale bluish-white to translucent, except dorsal fin pale yellow on basal half and anal fin with pale yellow stripe across middle of fin. Colour of male holotype in alcohol: generally pale yellowish tan, grading to brownish on upper parts and side of head; jaws noticeably paler (tan) than rest of head; iris yellowish; dark marking (see fresh coloration) on middle of back faintly evident; all fins translucent yellowish. Colour of female when fresh: pink above lateral line and on upper head, otherwise white; iris yellow; faint yellow, lateral stripe from upper pectoral base to middle of upper half of caudal-fin base; fins translucent to whitish. Colour of female paratypes in alcohol: generally pale tan, sometimes with slight hint of dark mid-lateral stripe; rear edge of caudal fin sometimes blackish. Remarks The new species belongs to an assemblage that we refer to as the Peaolopesia complex. Smith (1949) described the genus Peaolopesia for a single East African species, P. gymnogenys (Günther, in Playfair Fig. 2. Choerodon gomoni, female paratype (BPBM 33840), 88.5 mm SL, Chesterfield Islands, Coral Sea. Photo by J. E. Randall. 112

Gerald R. Allen and John E. Randall & Günther, 1867), based on its sparse cheek scalation. Although Gomon (1997) placed the genus in the synonymy of Choerodon, several additional species are closely related to C. gymnogenys and form a discrete group that is possibly worthy of sub-generic distinction. Additional members include: C. sugillatum Gomon, 1987 from northern Australia, C. margaritiferus Fowler and Bean, 1928 from the Philippines, C. japonicus (Kamohara, 1958) from Taiwan and Japan, and another undescribed East African species. The members of this group are morphologically similar and best separated on the basis of colour pattern, although cheek scalation and caudal peduncle depth are useful for some species (M. Gomon pers. comm.). Choerodon gomoni differs from all these species by virtue of its male and female colour patterns. Male colours are more distinct and best serve to contrast the various species in the Peaolopesia complex (Table II). Unlike most members of the genus, C. gomoni appears to form aggregations. A group of at least 50 individuals was seen swimming close to the rubble bottom at Bangang Island in the Banggai Group off central eastern Sulawesi. Most of them were females. Judging from our collections, the species is mainly found in relatively deep water. Collecting depths ranged from 30 to 82 m. Etymology The species is named gomoni in honour of Martin F. Gomon, Curator of Fishes at the Museum of Victoria in Melbourne, Australia in recognition of his contribution to the our knowledge of wrasses belonging to the tribe Hypsigenyini. He eventually plans to revise the genus Choerodon and has generously shared his knowledge of this group with us. Acknowledgements We thank Michel Kulbicki who assisted with the New Caledonia collections and sent data relating to the Alis trawling operations. Loreen R. O Hara and Arnold Suzimoto offered valuable assistance during the first author s visit to the Bishop Museum in March 2000. References Parenti, P. & J. E. Randall. 2000. An annotated checklist of the species of the labroid fish families Labridae and Scaridae. J. L. B. Smith Institute of Ichthyology Ichthyological Bulletin 68: 1-97. Fowler, H. W. & B. A. Bean. 1928. Contributions to the biology of the Philippine Archipelago and adjacent regions. The fishes of the families Pomacentridae, Labridae, and Callyodontidae, collected by the United States Bureau of Fisheries Steamer Albatross, chiefly in Philippine seas and adjacent waters. United States National Museum Bulletin 100 (7): 1-502. Gomon, M. 1987. New Australian fishes. Part 6. New species of Lepidotrigla (Triglidae), Choerodon (Labridae) and Zebrias (Soleidae). Memoirs of the Museum of Victoria 48 (1): 17-23. Gomon, M. 1997. Relationships of fishes of the labrid tribe Hypsigenyini. Bulletin of Marine Sciences 60 (3): 789-871. Kamohara,T. 1958. A review of the labrid fishes found in the waters of Kochi Prefecture, Japan. Reports of Usa Marine Biological Station 5 (2): 1-20. Playfair, R. L. & A. Günther. 1867. The fishes of Zanzibar. J. van Voorst, London, 153 pp. Smith, J. L. B. 1949. Interesting fishes of three new genera new to South Africa. Annual Magazine of Natural History (series 12) 2: 367-374. Table II. General distribution and male colour patttern features for described species in the Peaolopesia complex. Species Distribution Distinguishing colour marks C. gomoni Indonesia & New Caledonia Reddish blotch on middle of back; faint yellow lateral stripe. C. sugillatum N. Australia Blue bar on pectoral fin base; diagonal blue mark between dorsal and pectoral fins; blue spots on scales. C. japonicus Taiwan & Japan Yellow diagonal band on cheek; blue stripe on upper back; blue scale margins. C. margaritiferus Philippines Blue or white stripe below eye, continued as line of white or blue spots to upper pectoral base; white or blue bar on pectoral base; blue or white spots on scales. C. gymnogenys East Africa Purplish or mauve above diagonal between rear tip of opercle and last dorsal ray; blue stripe through eye and narrow blue lines on rear half of body. 113