Parapercis diplospilus Gomon, 1981

Matsunuma, Mizuki, Mazlan, Abd Ghaffar, Arshad, Aziz, Seah, Ying Giat, K., Siti Tafzilmeriam S. A., Ramasamy, Azwarina Azmi, Babaran, Ricard P., Fukui, Yoshino & Motomura, Hiroyuki, 2016, Distribution Range Extensions of Parapercis bicoloripes and P. diplospilus (Perciformes: Pinguipedidae) in the South China Sea and the Adjacent Waters, with Notes on Ontogenetic Changes in P. bicoloripes, Species Diversity 21, pp. 187-196 : 192-194

Parapercis diplospilus Gomon, 1981

( Figs 2 , 4A–B , 5; Tables 1–2)

Material examined. Eleven specimens, 44.2–74.1 mm SL. Thailand: KAUM –I . 22880, 67.5 mm SL, northern Gulf of Thailand, bottom trawl (obtained at Angsila fishing port, Chonburi Province); NSMT-P 55320 , 3 specimens, 44.2–54.9 mm SL, off Songkla; NSMT-P 70071 , 3 specimens, 66.5–70.4 mm SL, possibly Thailand (no further locality data); NSMT-P 70944 , 61.3 mm SL, Thailand (no further locality data); NSMT-P 115466 , 55.8 mm SL, Thailand (no further locality data) . Malaysia: KAUM –I. 16930, 54.1 mm SL, off Kuala Terengganu, Terengganu, bottom trawl (obtained at Cendering fishing port, Kuala Terengganu) . Philippines: KAUM –I. 80706, 74.1 mm SL, off Iloilo, Panay Island (obtained at Tigbauan Market , Iloilo), 11 November 2015 .

Description. Morphometrics, expressed as percentages of SL, and frequency distribution of selected meristics are shown in Tables 1–2. Dorsal-fin rays V, 22; anal-fin rays I, 18; pectoral-fin rays all branched except for uppermost ray; pelvic-fin rays I, 5; branched caudal-fin rays 15 (8 and 7 in dorsal and ventral series, respectively); pseudobranchial filaments 10 (1) or 11 (1); branchiostegal rays 6.

Body subcylindrical, moderately elongate, deep, depth at anal-fin origin 3.1–4.2 in SL; greatest width at pectoralfin base 3.4–5.0 in SL. Caudal peduncle short, deep, depth 0.8–1.0 in length. Head small, its length 1.6–2.7 in SL; snout short, pointed, its length subequal to orbit diameter; eye relatively large, fleshy orbit diameter 3.3–4.0 in HL; interorbital space narrow, least bony width 17.2–26.7 in HL.

Mouth small, slightly oblique, forming angle of about 20° to horizontal axis of head; lower jaw slightly protruding beyond upper jaw tip; posterior margin of upper jaw reaching vertical drawn through anterior margin of pupil. Upper jaw with outer row of 18–30 incurved caniniform teeth on each side (number increasing with growth), anterior 2–4 caniniform teeth slightly larger, other teeth increasingly smaller posteriorly; inner band of villiform conical teeth behind outer canine row of upper jaw, broadest anteriorly with 3–5 rows maximum, gradually narrowing posteriorly to 1 row at rear of jaw. Front of lower jaw with usually 4 pairs of incurved enlarged, caniniform teeth (3 and 4 on left and right sides, respectively, in KAUM–I. 16930; 7 or 8 in total) in distinctly separate outer row, innermost tooth usually smallest, its size about half that of other teeth; inner band of villiform conical teeth medial to caniniform teeth at front of lower jaw, broadest portion with about 5 tooth rows, followed by row of small, incurved conical teeth, 3–10 teeth in middle of tooth row slightly enlarged; vomer with crescentic patch of 2 or 3 rows of small conical teeth, subequal in size; palatine teeth absent.

Gill membranes free from isthmus, with broad free fold; developed gill rakers short and spinous, longest raker about one-fourth as long as longest gill filament. Nostrils small, anterior nostril with short membranous tube, its tip not reaching posterior nostril when laid back; posterior nostril pore ovate or elliptical with slightly raised rim.

Pores of cephalic sensory system connected by canals under skin. Row of 3–4 pores above maxilla; 3 pores near nostrils, including 1 pore above and 1 below posterior nostril, 1 between nostrils; 2 pores on anterior margin of snout; row of 11–14 pores in infraorbital series, with several branches in posterior portion; 10 or 11 pores in row on posterior margin of preopercle; interorbital space with 2–5 pairs of pores on anterior half, small pores scattered medially on posterior half; occiput with numerous small pores; ventral surface of lower jaw with 5 pores on each side, anteriormost pore behind chin.

Opercle bearing strong, posteriorly-directed, flattened spine, approximately at level of ventral edge of orbit in lateral view; posterior margin of subopercle well expanded posteriorly, with 13–19 serrae, upper serrae relatively large, number of serrae increasing with growth; posterior edge of interopercle with 2 or 3 weak serrae; preopercle rounded, posteroventral edge with about 6 serrae; posttemporal area with small exposed bony cleft with several indistinct bony protuberances on its posterior margin.

Lateral line continuous, about 3 pored lateral-line scales extending onto caudal fin; body entirely covered with developed ctenoid scales, scales on dorsolateral portion with ca. 40 cteni; head, including cheek, preopercle, interopercle, subopercle, and opercle, with ctenoid scales; no scales on snout, interorbital space, occipital area, or both jaws; bases of pectoral and caudal fins covered with small, elongate ctenoid scales; dorsal, anal, and pelvic fins without basal scales.

Origin of dorsal fin posterior to vertical drawn through upper origin of pectoral fin; dorsal-fin spines relatively short; 4th dorsal-fin spine longest; membrane between 5th spine and 1st soft ray attached near tip of 5th spine, deeply incised; anterior soft rays subequal in length, 3rd or 4th ray longest. Origin of anal fin below base of 5th dorsal-fin soft ray; anal-fin spine weak, slender; 4th soft ray longest. Caudal fin truncate to slightly rounded, upper edge (and lower edge in KAUM–I. 80766) slightly pointed. Pectoral fin slightly elongate, with rounded posterior contour, 7th or 8th ray longest, its tip reaching vertical drawn through anal-fin origin. Pelvic fin origin anterior to vertical drawn through pectoral-fin base, spine covered with skin closely attached to first soft ray; 4th soft ray longest, depressed tip almost reaching anus.

Fresh coloration. Body creamy-white, whiter ventrally, darkening dorsally and laterally. ( Fig. 4A–B ); lower half of lateral body surface above anal fin with transverse row of about 6 large, brown blotches. Head creamy-white, postorbital region and nape brownish. Snout with indistinct narrow brown band (width about half pupil diameter) extending from anterior margin of orbit to tip of snout. Cheek creamy-white, with 2 brown blotches below eye; anterior blotch small, situated between ventral margin of orbit and posterior tip of upper jaw; posterior blotch below posteroventral margin of orbit, with slight yellowish tinge. Eye yellow to dull orange, tinged with red posterodorsally; pupil black. Opercle generally brownish. Membrane of spinous portion of dorsal fin pale yellow; membrane between 1st and 3rd spines brownish. Soft-rayed portion of dorsal fin with pale yellow membrane and about 3 poorly defined brownish stripes. Anal-fin semi-translucent, membranes between each ray with brownish tinge. Pectoral-fin membrane semi-translucent, rays with brownish tinge, base with oblique narrow brown band. Pelvic fin pale yellow, with numerous minute melanophores throughout; spine and tips of soft rays white. Two small dark brown ocellated spots on caudal-fin base, subequal to pupil in size. Caudal-fin semitranslucent, with ca. 3 narrow, dull orange bands; posterior margin with narrow zone of dark orange tinge.

Distribution. Parapercis diplospilus is distributed in the southeastern Indian and western Pacific oceans ( Fig. 2 ): Nha Trang Bay, Vietnam ( Prokofiev 2008); Gulf of Thailand (this study); off Terengganu, Malaysia (east coast of Malay Peninsula) (this study); Visayan Islands, the Philippines ( Gomon 1981; this study); Kaimana, West Papua, Indonesia ( Allen and Erdmann 2009); Milne Bay, Papua New Guinea ( Allen and Erdmann 2012); and Australia, including Queensland ( Johnson 1999; Robins and McGilvray 1999), Northern Territory ( Larson et al. 2013), and Western Australia ( Hutchins 2001, 2003; Allen et al. 2006). Although Ambak et al. (2010) recorded the species from Malaysia, their photograph is re-identified here as P. bicoloripes (see above).

Remarks. The present specimens, from Thailand, Malaysia, and the Philippines, agree closely with the original description and figures of P. diplospilus given by Gomon (1981), including the diagnostic characters of the species [dorsal-fin rays V, 22, with last spine connected by deeply incised membrane to first soft ray; anal-fin rays I, 18; pectoral-fin rays 15; scale rows below lateral line 10; circumpeduncular scale rows 23; 7 or 8 (usually 4 pairs) of caniniform teeth in front part of lower jaw; and 2 prominent dark spots on caudal-fin base]. They differ slightly from Gomon (1981) in having a slightly longer fourth dorsal-fin spine, 7.1–8.2% SL (vs. 6.4–7.8% SL in the latter), regarded here as intraspecific variation. Gomon (1981) included a detailed comparison of P. diplospilus with P. ommatura Jordan and Snyder, 1902 ( Fig. 4C ), which is similar to the former in overall body appearance. Parapercis diplospilus can be readily distinguished from P.ommatura by the two dark spots on the caudal-fin base [vs. a single (upper) spot in the latter] and blotches on the cheek (vs. longitudinal stripes) ( Gomon 1981; Fig. 4 ).

Parapercis diplospilus , originally described by Gomon (1981) on the basis of 21 specimens from the Philippine islands, has subsequently been recorded from many localities in the southeastern Indian and western Pacific oceans, although not from the Gulf of Thailand or east coast of the Malay Peninsula . The present specimens, therefore, represent the first records of the species from these two localities.

The record of P. diplospilus from Nha Trang Bay ( Prokofiev 2008) may need to be reviewed, as the five Vietnamese specimens described differed significantly from Gomon’s (1981) description in having 17 or 18 pectoral-fin rays (vs. 14–16 in the latter), six caniniform teeth on the front part of the lower jaw (vs. seven or eight), and a relatively great- er pelvic-fin length of 25.6–27.5% SL (vs. 19.9–23.6% SL). Of these characters, dentition has been treated as an important diagnostic feature of Parapercis species ( Cantwell 1964) . In addition, Prokofiev (2008) considered the difference in pelvic-fin length of the Vietnamese specimens as likely size-related intraspecific variation [the latter specimens being smaller, 37–45 mm SL vs. 48.7–78.0 mm SL in Gomon (1981)]. However, the smallest specimen examined here (44.2 mm SL, one of NSMT-P 55320; Fig. 5) clearly had relatively shorter pelvic fins than the Vietnamese specimens (23.0% SL in the former vs. 25.6–27.5% SL in the latter). Moreover, Prokofiev (2008) stated that the posterior tip of the depressed pelvic fin extended well beyond the anal-fin origin in the Vietnamese specimens, such not being so in the present smallest specimen. However, the relationship between pelvic-fin length and standard length can not be considered further here due to the limited material available.

Comments on records of Parapercis ommatura . Shimada (2013) considered Parapercis ommatura Jordan and Snyder, 1902 to be distributed in the northwestern Pacific Ocean, including China, Taiwan, and Japan. Although Prokofiev (2008) recorded P. ommatura from Nha Trang Bay, Vietnam, Liao et al. (2011) included P. ommatura sensu Prokofiev (2008) in the synonymy of their new species, Parapercis lutevittata Liao, Cheng, and Shao, 2011 . Recently, Ray et al. (2015) recorded P. ommatura , based on 21 specimens (71.9–100.0 mm SL), from the northern Bay of Bengal, off West Bengal, India. These specimens differed slightly from P. ommatura [as redescribed by Imamura and Yoshino (2007) on the basis of 16 specimens (64.5– 101.9 mm SL), including the holotype of the species, from Japan and China] in having 13–14 gill rakers (vs. 8–13 in the latter) and 61 or 62 lateral-line scales [vs. 56–58; 56–60 in Shimada (2013)]. Moreover, the Indian specimens also differed from P. ommatura from the northwestern Pacific ( Shinohara 1997; this study, Fig. 1C ) in coloration, including bright orange stripes on the cheek ( Ray et al. 2015: fig. 1) (vs. brownish in the latter) and a small, black spot on each membrane between the third and fifth dorsal-fin spines (vs. absent). Accordingly, the Indian specimens recorded by Ray et al. (2015) may represent a species distinct from P. ommatura .

Comparative material. Parapercis diplospilus: UPVMI 316, 57.5 mm SL, off Iloilo, Panay Island, Philippines (obtained at Central Market, Iloilo City) (photograph only). Parapercis ommatura: BSKU 81924, 84.6 mm SL, Tosa Bay , Kochi Prefecture, Japan, 30 m depth, RV Toyohata-maru .

Figures

Fig. 2. Distribution of Parapercis bicoloripes (triangles) and P. diplospilus (circles). Closed and open symbols indicate previously known and new records, respectively.

Fig. 4. Fresh specimens of Parapercis diplospilus from Thailand (A) and the Philippines (B), and P.ommatura from Japan (C). A, KAUM–I. 22880, 67.5mm SL, northern Gulf of Thailand; B, KAUM–I. 80706, 74.1mm SL, off Iloilo, Panay Island; C, BSKU 81924, 84.6mm SL, Tosa Bay, Kochi Prefecture.

Fig. 1. Fresh specimens of Parapercis bicoloripes from Malaysia (A–B) and the Philippines (C). A, KAUM–I. 79754, 136.0mm SL, off Kuala Terengganu; B, KAUM–I. 16935, 120.4mm SL, off Kuala Terengganu; C, KAUM–I. 69435, 66.1mm SL, off Miagao, Iloilo, Panay Island.