Wrasses of the Galápagos Islands, with the description of a new deepwater species of Halichoeres (Perciformes: Labridae) - PDF

Rev. Biol. Trop. 49 Supl. 1: , 2001 Wrasses of the Galápagos Islands, with the description of a new deepwater species of Halichoeres (Perciformes: Labridae) Carole C. Baldwin 1 and John E. McCosker

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Rev. Biol. Trop. 49 Supl. 1: , 2001 Wrasses of the Galápagos Islands, with the description of a new deepwater species of Halichoeres (Perciformes: Labridae) Carole C. Baldwin 1 and John E. McCosker 2 1 Department of Vertebrate Zoology, MRC 159, National Museum of Natural History, Smithsonian Institution, Washington, D.C , U.S.A. Fax: ; 2 California Academy of Sciences, San Francisco, California 94118, U.S.A. Fax: ; Received: 18-X-2000 Corrected: 23-XI-2000 Accepted: 8-XII-2000 Abstract: Halichoeres raisneri, new species, is described from three specimens captured by the Johnson Sea Link submersible at m off Wolf Island, Galápagos. Distinctive features of the new species include a dorsally projecting fleshy flap along the posterior three-quarters of the upper lip and the absence of a canine tooth at the corner of the upper jaw. The body color of freshly caught females is pale pink with two yellow stripes and five prominent pink spots above the uppermost stripe. Similarities between the new species and other labrids are discussed, and a key to the 16 nominal species of Labridae known from the Galápagos Islands is provided. Decodon melasma is recorded from the Archipelago for the first time. Key words: Labridae, Galápagos Islands, Submersible, New Species, New Records The nearshore fish fauna of the Galápagos Islands has intrigued ichthyologists and zoogeographers since Darwin returned to England with the first specimens for study. His collection of 15 specimens included a large wrasse that was later named Cossyphus d a rw i n i (now Semicossyphus darw i n i [Jenyns]) in his honor. The 16 labrids known from the Archipelago represent the fourth largest family of shorefishes, after 25 serranids, 23 carangids, and 19 muraenids. Most of the Galápagos labrid species are variously distributed from Baja, California, to central Chile, and occur at one or more of the other tropical eastern Pacific Islands (Clipperton, Cocos, Malpelo, Revillagigedos); several also are known from Indo-Pacific localities. Only the new species described herein and an undescribed species of Xyrichtys (Victor and Wellington 2000) are currently known only from the Galápagos, and one species, Xyrichtys victori, is an insular endemic (Cocos and Galápagos). Based on three months of scuba and submersible diving using the Harbor Branch Oceanographic Institute s Johnson Sea-Link (JSL) at Galápagos (during November, 1995, a normal period in the eastern Pacific, and June and July, 1998, a severe El Niño Southern Oscillation period), we are able to add additional records and observations about Galápagos labrids. Grove and Lavenberg (1997) published the first comprehensive listing and analysis of Galápagos labrids, along with black and white drawings and color photographs of many species. McCosker (1998) corrected several errors in their work and analysis, 90 R E V I S TA DE BIOLOGIA T R O P I C A L based primarily on Randall s (1995) analysis of eastern Pacific Thalassoma. Useful keys to the species of eastern Pacific labrids and supplementary information may be found in Bussing (1985, for Costa Rican species) and Gomon (1995, for eastern Pacific species, excluding Galápagos). Excellent color photographs of growth stages of most Galápagos species are available in Humann (1993) and Allen and Robertson (1994). During 1995, the junior author and R. Grant Gilmore observed and captured from the JSL the first known Galápagos specimens of the blackspot wrasse, Decodon melasma Gomon. They were first observed (7 Nov. 1995, JSL Dive 3941) over sand, rock, and rock ridge bottoms at 104 m at Española (=Hood Island) and subsequently collected (15 Nov. 1995, JSL Dive 3954) from similar habitats off Cabo Hammond, Isla Fernandina (=Narborough Island), at m. The two specimens (CAS , mm SL) are typical of the species, which is also known from the Gulf of California to Peru and Cocos Island (Allen and Robertson 1994, Gomon, 1995). Another wrasse, resembling Halicho - eres chierchiae Di Caporiacco, was observed on 25 July 1998 at North Seymour Island in Galápagos, but it was not collected or photographed. The individual, with a prominent red and blue spot above the posterior tip of the pectoral fin typical of an adult male (and from which the common name wounded wrasse is derived), was spotted over a sand and rock field. We include H. chierchiae, which is otherwise known from Baja California to Panama (Gomon 1995, pers. obs.), in the key to Galápagos labrids herein, but further investigation is needed to confirm its presence in Galápagos. Finally, as noted above, Victor and Wellington (2000) report on an undescribed species of Xyrichtys from Galápagos. MATERIALS AND METHODS Institutional abbreviations follow Leviton et al. (1985). SL refers to standard length, HL, to head length. Measurements and most counts follow those of Randall and Smith (1982). Counts of scale rows between lateral line and fin origins do not include small scales at base of fins or the lateral-line scale. Pored lateral-line scale counts include the terminal scale on the caudal-fin base posterior to the hypural plate. Counts of vertebrae, caudal-, dorsal- and anal-fin rays, and lengths of first anal- and first dorsal-fin spines were taken from or verified with radiographs. Other measurements were made with dial calipers to the nearest 0.1 mm. The branchial skeleton of one paratype was removed and cleared and stained to facilitate examination of pharyngeal dentition. Comparative labrid material examined: Halichoeres bicolor, USNM , 5 specimens; H. bimaculatus, USNM , 1; H. biocellatus, USNM , 1; H. bivittatus, USNM , 2; H. caudalis, U S N M , 1; H. dispilus, USNM , 2; USNM , 5; H. garnoti, U S N M , 18; H. hortulanus, USNM , 2; H. kallochroma, USNM , 2; H. margaritaceus, USNM , 9; H. mar - ginatus, USNM , 1; USNM , 10; H. nicholsi, USNM , 4; H. noto - spilus, USNM , , 5; H. ornatis - simus, USNM , 1; H. papilionaceus, USNM , 2; H. pelicieri, U S N M , 1 paratype; H. podostigma, USNM , 3; H. prosopeion, USNM , 1; H. scapularis, USNM , 3; Pseudoju - loides cerasinus, USNM , 1. Geographical distributions of species provided in the key to Galápagos labrids include information from Allen and Robertson (1994), Bearez (1996), Robertson and Allen (1996), Grove and Lavenberg (1997), and D. Ross Robertson (pers. comm.). References for original descriptions of all labrid species mentioned herein can be found in Eschmeyer (1998) or online at the following address: I N T E R N AT I O N A L J O U R N A L OF T R O P I C A L B I O L O G Y AND CONSERVAT I O N 91 Key to the Labridae of the Galápagos Islands (Modified from Gomon 1995) 1a. Lateral line interrupted (Fig. 1a) b. Lateral line continuous (Fig. 1b, c), abruptly curved downward in some species Fig. 1. Variation in the shape of the lateral line among eastern Pacific Labridae (from Gomon, 1995). 2a. Dorsal profile of snout not very steep, forming an angle of about 45 with the longitudinal axis of the body (Fig. 2a); top of head and snout somewhat compressed, but not forming a knife-like edge; adults greenish brown with white spots on each body scale; juveniles green, red, or brown, with white spots on body and head, and 3-4 thin brown body bands novaculichthys taeniourus (Lacepède) (Indo-Pacific; eastern Pacific, from Gulf of California to Panama and the Galápagos and Clipperton Islands) 2b. Dorsal profile of snout steep, forming an angle with longitudinal axis of the body that is noticeably more than 45 and sometimes almost vertical (Fig. 2b); top of head and snout compressed into a knife-like edge (Xyrichtys 1 ).3 Fig. 2. Shape of the dorsal profile of the head in (a) Novaculichthys and (b) Xyrichtys (from Gomon, 1995). 3a. First 2 dorsal-fin spines elongate and well separated from remainder of dorsal fin; body with 4 indistinct broad brown bands Xyrichtys pavo (Valenciennes) (Indo-Pacific, including Hawaii and Red Sea; Gulf of California to Panama and Galápagos) 3b. First dorsal spines not elongate, not separated from remainder of dorsal fin; terminal phase iridescent blue-green with scattered black blotches on flanks; initial phase mainly pinkish orange, without blotches or spots; juveniles white to ye-llowish brown with dark stripe on upper flank xyrichtys victori Wellington (Cocos and Galápagos Islands) 4a. Lateral line smoothly curved (Fig. 1b); dorsal-fin spines XI or XII b. Lateral line curved abruptly downward beneath posterior end of dorsal fin (Fig. 1c); dorsal-fin spines VIII or IX a. Dorsal-fin spines XI; anal fin with 10 segmented rays; predorsal scales reaching a vertical anterior to orbit; coloration reddish above, pale below, 3 bright yellow stripes on head and a black blotch above the pectoral fin Decodon melasma Gomon (Gulf of California to Peru, Cocos and Galápagos Islands) 92 R E V I S TA DE BIOLOGIA T R O P I C A L 5b. Dorsal-fin spines XII; anal fin with 12 segmented rays; predorsal scales reaching or nearly reaching a vertical through posterior margin of orbit; coloration not as above a. Scaly basal sheath absent on dorsal and anal fins; pored lateral-line scales; initial phase red with a pale chin and a yellow blotch above the pectoral-fin base, terminal phase dark gray with a pale chin and an obvious large yellow spot above the pectoral-fin base Semicossyphus darwini (Jenyns) (mainland Ecuador to central Peru, and Galápagos) 6b. Scaly basal sheath present on dorsal and anal fins; pored lateral-line scales; coloration not as above (Bodianus ) a. Terminal phase with a pronounced bump on forehead and elongate rays in median fins; body coloration of juveniles and initial phase yellow, the anterior 2/3 becoming pinkish in adult females, with two black stripes on upper half of flank, beginning behind eye and extending to caudal base; body coloration of terminal male gray to green with a faint yellow bar at mid-body, head pinkish, chin white bodianus diplotaenia (Gill) (Baja California to northern Chile, Clipperton, Cocos, Revillagigedos, and Gálapagos Islands) 7b. Terminal phase without an exaggerated forehead bump, median fins not greatly elongated; body coloration of juveniles pale yellow to white, with three black stripes on head and body, the middle stripe beginning on the snout and extending to the caudal fin; body coloration of adults extremely variable, from brown to dark gray to bright orange and white, overlain with black blotches Bodianus eclancheri (Valenciennes) (mainland Ecuador to central Chile, and Galápagos) 8a. Dorsal-fin spines VIII (Thalassoma) b. Dorsal-fin spines IX a. Branched pectoral-fin rays 13; caudal fin truncate; juveniles, females, and primary males with lengthwise bands of yellowish brown and red on head and body; secondary males with a greenish purple head, a broad yellow vertical band in the thoracic region, and the remainder of the body greenish blue; maximum size 15 cm SL Thalassoma lucasanum (Gill) (Gulf of California to mainland Ecuador, Cocos, Galápagos, and Malpelo) 9b. Branched pectoral-fin rays 14; caudal fin of terminal phase with elongate lobes; coloration green or blue-green with 2-3 radiating lines from eye; adults larger, may attain 43 cm SL a. Coloration green or blue-green with a slender red streak on each scale; head pink with green lines behind and beneath eye; may attain 24 cm SL Thalassoma grammaticum Gilbert (Gulf of California to Panama, Clipperton, Cocos, Galápagos, and Revillagigedos Islands) 10b. Coloration green, with red stripes and vertical lines along body, and red lines behind eye and on snout and forehead; may attain 43 cm SL Thalassoma purpureum (Forsskål) (Indo-Pacific eastward to Clipperton, Cocos, Galápagos, and Panama) 11a. Anterior jaw teeth not enlarged, most teeth incisor-like (Fig. 3a); initial phase gray, with fine white speckling on upper half and 2 black spots over caudal-fin base; terminal phase greenish dorsally, pale ventrally, with thin blue stripes before and behind eye, and a red-orange patch above pectoral base.... Stethojulis bandanensis (Bleeker) (western Pacific to Costa Rica, Panama, Clipperton, Cocos, and Galápagos Islands) Fig. 3. Dentition in (a) Stethojulis and (b) Halichoeres (from Gomon, 1995). I N T E R N AT I O N A L J O U R N A L OF T R O P I C A L B I O L O G Y AND CONSERVAT I O N 93 11b. Anterior jaw teeth enlarged and canine-like (Fig. 3b); color not as above (Halichoeres) a. Upper jaw with one or more prominent canines at corner of mouth; dorsal fin with 11 segmented rays b. Upper jaw without prominent canines at corner of mouth; dorsal fin with 11 or 12 segmented rays a. Each lateral-line scale usually with only a single pore; body coloration pink to orange (live individuals capable of turning blue) with distinct black spot above middle of pectoral fin halichoeres dispilus (Günther) (Gulf of California to Peru, Galápagos, and Cocos) 13b. Each anterior lateral-line scale usually with 2-3 pores; coloration not as above a. Terminal phase greenish blue with green bars above midbody, yellow to greenish yellow below, purple midlaterally with a prominent red and blue spot above pectoral fin tip; initial phase greenish with purple bars above, yellow below, an orange reticulated pattern midlaterally and a black spot on segmented portion of dorsal fin Halichoeres chierchiae Caporiacco (Baja California to Panama and Galápagos) 14b. Terminal phase greenish blue with a diffuse black bar on upper body near distal tip of pectoral fin, a prominent yellow blotch preceding it; initial phase pale yellow with irregular dark blotches on sides and a large dark green ocellus on dorsal fin halichoeres nicholsi (Jordan & Gilbert) (Gulf of California to mainland Ecuador, Revillagigedos, and Galápagos) 15a. Segmented dorsal rays 12; a prominent fleshy skin flap at posterior end of upper lip; coloration of living females pale pink with 2 prominent yellow body stripes and 5 prominent pink spots above uppermost yellow stripe halichoeres raisneri n. sp. (Wolf Island, Galápagos) 15b. Segmented dorsal rays 11; upper lip may be creased, but prominent posterior skin flap absent; coloration of initial phase dark green above, light green below, with 5-6 alternating yellow and black patches at base of dorsal fin; terminal phase with 7-8 blackish bars on upper half of body separated by narrow yellow bars, a blackish patch behind pectoral fin halichoeres notospilus (Günther) (Gulf of California to Peru, Galápagos and Revillagigedos Islands) 1 not included is an undescribed species of Xyrichtys from Galápagos (Victor and Wellington 2000) Halichoeres raisneri, new species Figs. 4-5, Table 1 Holotype: USNM , 90.0 mm SL, female, SE Wolf Island, Galápagos, N, W, 115 m, JSL II Sta. 3087, C. Baldwin and J. Gomezjurado, 22 June Paratypes: CAS , 78.8 mm SL, female, and 39.8 mm SL, sex undetermined, SE Wolf Island, Galápagos, N, W, m, JSL II Sta. 3086, C. Baldwin and J. McCosker, 22 June Diagnosis: Halichoeres raisneri is distinguishable from other species of the genus on the basis of the following combination of characters: posterior three-quarters of upper lip with dorsally projecting fleshy flap similar to ventrally projecting flap on lower lip; no canine tooth at corner of upper jaw; body color (of freshly caught female) pale pink with two prominent yellow stripes, one from tip of snout to upper caudal-fin base, the other from pectoral-fin base to lower caudal-fin base; five prominent pink spots above upper yellow stripe, dispersed along lateral line; no dark blotch on caudal-fin base; lateral-line complete, abruptly deflected downward below posterior end of dorsal fin; 27 tubed scales in series, tubes simple and with single opening; ultimate pored scale located on caudal-fin base; dorsal-fin rays IX,12; anal-fin rays III,12, first spine visible without dissection; head naked; scales on chest region smaller than other body scales; upper and lower jaws each with a pair of canine teeth near symphysis and with a series of conical 94 R E V I S TA DE BIOLOGIA T R O P I C A L Fig. 4. Top: Holotype of Halichoeres raisneri, new species, USNM , 90.0 mm SL, Wolf Island, Galápagos Islands. Middle: Paratype of H. raisneri (prior to conservation), CAS , 78.8 mm SL. Bottom: In situ photograph of H raisneri, JSLII Sta I N T E R N AT I O N A L J O U R N A L OF T R O P I C A L B I O L O G Y AND CONSERVAT I O N 95 Fig. 5. Right lateral view of head. (a) Halichoeres raisneri, holotype, USNM , 90.0 mm SL; (b) Halichoeres dispilus, USNM , 106 mm SL. teeth posterior to canines; free margin of vertical preopercular limb smooth, reaching dorsally to horizontal through ventral edge of eye, free margin of horizontal preopercular limb smooth, reaching anteriorly to vertical through front of eye; snout long, length 26-29% HL; body slender, depth 20-22% SL; and caudal peduncle narrow, depth less than or approximately equal to length. Description: Data for morphometric features are given in Table 1. Dorsal-fin rays IX,12; anal-fin rays III,12; pectoral-fin rays 12; principal caudal-fin rays 8+7 (8+8 segmented rays), procurrent caudal-fin rays 5+4 (5+5 unsegmented rays); vertebrae 10+15; lateral-line scales 27; scale rows between lateral line and dorsal-fin origin 2; scale rows between lateral line and anal-fin origin 7; suborbital pores (from posterior point of orbit to and including lacrimal) 9; gill rakers (18 in holotype, 16 in 78.8-mm SL paratype, too small to accurately count in 39.8-mm paratype). Mouth terminal and of moderate size, upper jaw reaching vertical through anterior nostril. Lips fleshy, lower lip with a broad flap projecting ventrally, posterior three-quarters of upper lip with more slender flap projecting dorsally (Fig. 5A). Inner surface of lips near base of teeth strongly papillose. Upper and lower jaws each with a pair of large, forward-projecting canine teeth near symphysis, lower pair sliding between upper pair when mouth closed. A single row of conical teeth in both jaws posterior to canine teeth, about 9 in upper jaw, 10 in lower jaw teeth of 78.8-mm SL paratype damaged and counts not included; single row of very small nodular teeth in single row posterior to conical teeth, about 6 in upper jaw in holotype, 8 in lower jaw nodular teeth in paratypes, if present, small and difficult to discern. A few tiny teeth present in both jaws behind canine teeth and medial to anteriormost conical teeth. Pharyngeal dentition of 78.8-mm SL paratype comprising paired upper third-pharyngeal tooth plates and median lower toothplate formed by fused fifth ceratobranchials. Upper tooth plates roughly triangular, with 17 teeth in five transverse rows; first (anteriormost) row with a single tooth, second with three, third with four, fourth with five, fifth (posteriormost) with four; size of teeth decreasing posteriorly; all teeth roughly conical but with broad bases and slender, curved tips. Lower pharyngeal plate a shallow Y shape in dorsal view with teeth covering all but the distal upper arms of the Y. Posterior end of stem with a single row of three teeth, broadening to two rows of ca. four teeth anteriorly on stem; curved part of plate with 96 R E V I S TA DE BIOLOGIA T R O P I C A L TABLE 1 Data on morphometric features of type specimens of Halichoeres raisneri. Standard length is in mm; other measure - ments, in percentage of standard length. Holotype Paratypes USNM CAS Standard length (mm) Depth of body Width of body Head length Snout length Orbit diameter Body interorbital width Length of upper jaw Least depth of caudal peduncle Length of caudal peduncle Predorsal length Length of dorsal-fin base Length of depressed dorsal fin Length of first dorsal-fin spine Length of ninth dorsal-fin spine Length of anal-fin base Length of depressed anal fin Length of first anal-fin spine Length of third anal-fin spine Length of upper segmented caudal-fin rays Length of central segmented caudal-fin rays Length of pectoral fin Length of pelvic fin about four rows of teeth, those i
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