Synodus pacificus, Ho, Hsuan-Ching, Chen, Jen-Ping & Shao, Kwang-Tsao, 2016

Ho, Hsuan-Ching, Chen, Jen-Ping & Shao, Kwang-Tsao, 2016, A new species of the lizardfish genus Synodus (Aulopiformes: Synodontidae) from the western Pacific Ocean, Zootaxa 4162 (1), pp. 134-142 : 135-139

Synodus pacificus sp. nov.

New English name: Omega Lizardfish

Figs. 1 A–C, 2A, 3A, C, E, G, I; Tables 1–2

LSID:zoobank.org:act:BD6AFDFF-6E72-4296-BB92-C4166C59647A

Holotype. NMMB-P 22438 (121.7 mm SL), off Ke-tsu-liao, Kaohsiung, southwestern Taiwan , Taiwan Strait, cs. 100 m, 20 Jan. 2015, coll. H.- C. Ho.

Paratypes. 24 specimens, 82.9-204 mm SL. ASIZP 56567 (1, 204), 18 Jan. 1990; ASIZP 56568 (3, 154.4– 172) and ASIZP 62227 (1, 143); 25°25’23”N, 121°56’30”E, Huaping Island [ Pinnacle Island ], Keelung, N . Taiwan, 17 Feb. 1990 . BSKU 50396 (1, 185.2 mm SL), Taiwan. NMMB-P 22439 (11, 97.7–152.2 mm SL), collected from near the type locality, 20 Jan. 2015 . NMMB-P 22893 (2, 106.8– 121.7 mm SL), collected from near the type locality, 11 Feb. 2015. MNHN 2005-1492 (1, 108.7), 12°03’00”N, 121°28’58.8”E, Philippine , 120–123 m, 4 Jun. 1985 . MNHN 2014-0341 (1, 133,8), 22°15’48”S, 167°07’54”E, New Caledonia, 260–270 m, 25 Oct. 2008 . MNHN 2014-2244 (3, 82.9–107.6), 19°42’41.7”S, 158°26’28.5”E, Coral Sea , 225–239 m, 17 Oct. 2005 .

Diagnosis. A new species of Synodus with needle-like posterior processes of the pelvic girdle, differing from its congeners by having following combination of characters: 4 upside-down omega-shaped marks on the lateral body; 4 brown saddles on the dorsal surface; black patches on the nape and operculum; bars on the dorsal and caudal fins; orbital large (6.7–8.1% SL); interorbital space narrow (2.1–2.8% SL); snout short (6.3–7.2% SL); anterior palatine teeth not longer than posterior teeth; pectoral fin extending slightly beyond a line from base of pelvic fin to origin of dorsal fin; 7 peritoneal spots; peritoneal membrane pale; nasal flap flames-like, long and pointed; dorsal-fin rays 11–13 (mainly11); anal-fin rays 9–11 (10 or 11); pectoral-fin rays 11–14 (mainly 12); total vertebrae 52–54; pored lateral-ling scales 52–54; transverse scale rows above lateral line 3.5, below 4.5 or 5; gill rakers 31–37; and 17–29 teeth on free end of tongue.

Description. Morphometric and meristic data of the type series are provided in Table 1 . Data are provided for the holotype first, followed by that for paratypes in parentheses.

Dorsal fin rays 11 (11–14, mainly 11), all branched except for the first two, the last ray branched to base, the first ray slightly more than two-thirds of second ray in length; anal-fin rays 10 (9–11, mainly10 or 11), all unbranched except the last, branched to base; pectoral-fin rays 12 (11–13, mainly12), the upper two and lowermost unbranched; pelvic-fin rays 8, each ray with a slender posterior branch, except first and last, the first ray about twothirds of the longest ray in length; principal caudal-fin rays 19, the upper and lower unbranched; pored lateral-line scales 54 (52–54), not including 1 or 2 smaller scales caudal fin base; scale rows between lateral line and dorsal fin 3.5; scale rows below lateral line to origin of anal fin 5; median predorsal scales 16 (16–18); circumpeduncular scales 17; rakers on first gill arch 34 (31–37), 12 (10–13) on upper limb and 22 (21–25) on lower limb; vertebrae 54 (52–54); peritoneal spots 7 in all types (dissection required), the first one well in front pelvic-fin base, followed by 5 evenly distributed on inner wall of abdomen, and the last beside or slightly behind the anus.

Body slender, body width 7.4 (6.5–8.0) in SL; head length 3.8 (3.5–3.9) in SL; snout length 4.2 (3.8–4.2) in HL; orbital diameter 3.6 (3.5–4.1) in HL; interorbital space narrow, slightly concave when viewed anteriorly, the least bony width 10.2(9.5–12.2) in HL; caudal peduncle depth 5.5 (5.5–6.2) in HL; caudal peduncle length 2.3 (2.3–3.2) in HL.

Mouth terminal and slightly oblique, forming an angle of about 15° to horizontal axis of body; mouth very large, extending to a ventral position of the posterior half of the eye, the upper jaw length 1.7 (1.6–1.8) in HL; teeth in jaws needle-like, the largest arrow-tipped, about equal in length to pupil diameter, and angling medially and anteriorly, except for a few teeth at front of jaws; teeth of upper jaw in 3 close-set rows, those of outer row fixed, rather widely spaced, and largely covered by lip, medium and inner rows inwardly depressible, outer row about twice length of inner and medium teeth; teeth in lower jaw in 4 close-set rows, progressively smaller laterally, except for 2 or 3 enlarged anterior teeth, outermost row fixed, rather widely spaced and hidden by lip, the other rows inwardly depressible; palatine teeth in 2 rows, those on anterior half of inner row slightly longer than those on posterior half and outer row, but not forming a patch; no teeth on vomer; about 17 (17–29) posteriorly depressible teeth in 2 or 3 irregular rows on anterior part of tongue, followed by a relatively narrow tooth band bearing 2 (2 or 3) irregular rows of smaller teeth.

Anterior nostril on a line from upper edge of orbit to tip of snout, half way to base of upper lip; membranous posterior flap of anterior nostril a slender, flames-shaped flap ( Fig. 2 A), the pointed tip reaching well beyond posterior margin of posterior nostril when laid back; posterior nostril nearly round, with only a slight rim at front, directly behind anterior nostril, the internarial distance about equal to posterior nostril diameter.

Predorsal scales extending forward to about half of orbital diameter behind eye dorsally; posterior cheek fully scaled, with 5 slightly oblique latitudinal rows, progressively smaller posteriorly; a row of 5 scales onanterior part of opercle, each crossed by a sensory canal with 2 or 3 pores, the first in preopercular canal; remaining scales on opercle large and embedded except for a few large scales dorsally; no scales on dorsal, anal and paired fins; a broad central zone of scales basally on caudal fin, ending in a pair of very large pointed scales, 1 in each lobe, nearly reaching margin of fork of fin; a triangular scaly process at base of pelvic fin.

Predorsal length equal to distance from dorsal-fin origin to rear base of adipose fin, 2.4 (2.4–2.5) in SL; dorsal-fin base 2.2 (1.7–2.3) in HL; 3rd (2nd or 3rd) dorsal-fin ray longest, 1.7 (1.7–2.0) in HL; anal-fin base 2.7 (2.5–3.0) in HL; third anal-fin ray longest, 3.5 (3.3–4.6) in HL; caudal-fin forked, the lobes pointed, upper lobe 1.6 (1.4–1.9) in HL; middle caudal-fin rays 3.4 (3.3–4.1) in HL; pectoral fins extending slightly beyond a line connecting origins of dorsal and pelvic fins, the fin rounded when spread, 2.0 (1.8–2.2) in HL; sixth pelvic-fin ray longest, the fin length 1.3 (1.2–1.3) in HL.

S. pacificus sp. nov. S. macrops Coloration. When fresh, body overall bluish gray with pale ventral surface; two broad bands cross lower jaw; upper lip blackish; 4 small black patches on nape near pterotic region; large deep-brown patches on opercle, subopercle and preopercle; 4 upside-down omega-shaped marks along the axis of lateral body, each extending ventrally to level of lower pectoral-fin base, the 1st below origin of dorsal fin, the 2nd at middle on body, the 3rd above anterior half of anal fin, and the last at a short distance before caudal-fin base; 4 slightly-defined saddles on dorsal surface, each connects the omega-shaped marks on lateral sides of body; smaller, indistinct mark alternating between omega-shaped marks, the first one just behind pectoral-fin base; narrow irregular bar on caudal-fin base; 4 black oblique bands on dorsal fin; caudal fin yellowish with white posterior margins, 4 poorly-defined oblique bands on both lobes of the fin, the last band very broad and forming margin in some paratypes; pectoral, pelvic, anal, and adipose fins white. When preserved, dorsal half of body grayish to brownish and ventral surface (from 2 scale rows below the lateral line) white, forming strongly contrasting ventral surface. All black marks as described above but paler.

Distribution. Known from the type series collected from western Pacific Ocean off northern and southwestern Taiwan, the Philippines, and New Caledonia at depths of about 100 m to 270 m.

Etymology. The specific name pacificus is from Pacific Ocean, in reference to the collection localities of the type series.

Figures

FIGURE 1. Synodus pacificus sp. nov. A. Holotype, NMMB-P 22438, 121.7 mm SL, fresh. B. Holotype, preserved. C. Paratype, ASIZP 56567, 204 mm SL, fresh. D. Fresh specimen, ca. 130 mm SL, not retained. E. Synodus macrops Tanaka, NMMB-P 22441, 142.4 mm. SL, preserved.

FIGURE 2. Nasal flap on posterio rim of right posterior nostril, dorsal view when the flap fully depressed anteriorly. A. Synodus pacificus sp. nov. a, holotype, 121.7 mm SL; b, paratype, 147.1 mm SL; c, paratype, 152.2 mm SL; d, 127.6 mm SL. B. Synodus macrops Tanaka, e, 163.6 mm SL; f, 168.5 mm SL; g, 145.8 mm SL, h, 135.0 mm SL. Not to scale.

Tables

TABLE 1. Morphometric data of type series of Synodus pacificus sp. nov. and Synodus macrops Tanaka.

	S. pacificus sp. nov.		S. macrops
	Holotype Selected types		Non-types
SL(mm)	121.7 103.5–152.2 (n=12)		135.0–168.5 (n=9)
In %SL	Mean (Range)	SD	Mean (Range)	SD
Head length	26.3 27.1 (25.8–28.4)	0.8	26.2 (25.4–27.0)	0.5
Body width	13.6 13.7 (12.5–15.3)	0.8	12.6 (10.6–13.7)	0.9
Snout length	6.3 6.8 (6.3–7.2)	0.3	5.7 (5.3–6.5)	0.4
Orbital diameter	7.3 7.3 (6.7–8.1)	0.4	6.6 (6.1–7.3)	0.4
Interorbital width	2.5 2.5 (2.1–2.8)	0.2	2.5 (2.3–2.9)	0.2
Upper-jaw length	15.1 16.4 (15.1–17.3)	0.7	15.0 (14.1–15.6)	0.5
Predorsal length	40.9 41.0 (40.1–42.3)	0.6	39.8 (38.0–41.3)	1.0
Preanal length	77.7 76.8 (74.4–78.0)	1.1	77.5 (75.7–79.7)	1.3
Pre-adipose length	84.0 83.4 (80.9–84.6)	1.0	83.2 (81.9–84.3)	0.8
Prepelvic length	34.6 35.5 (33.9–37.0)	1.1	34.0(32.7–35.8)	1.1
Dorsal-fin base	12.1 13.0 (12.1–15.0)	1.0	11.9 (11.0–13.0)	0.8
Longest dorsal-fin ray	14.5 15.0 (13.9–16.3)	0.8	13.4 (12.8–13–9)	0.4
Anal-fin base	9.6 10.2 (9.1–11.5)	0.7	9.2 (7.7–10.0)	0.7
Longest anal-fin ray	7.5 7.2 (6.2–8.4)	0.5	6.2 (5.8–6.9)	0.4
Pectoral-fin length	13.1 13.1 (12.5–14.3)	0.6	10.8 (10.1–11.9)	0.6
Pelvic-fin length	20.7 21.3 (19.9–23.0)	1.0	17.5 (16.3–18.7)	0.8
Caudal-peduncle depth	4.8 4.7 (4.3–5.2)	0.3	4.1 (3.5–4.8)	0.5
Caudal-peduncle length	11.3 10.1 (8.8–11.3)	0.7	10.3 (8.8–11.3)	0.8
Caudal-fin length	16.3 16.0 (14.9–17.8)	0.8	14.4 (13.7–15.9)	0.7
Middle Caudal-fin ray	7.7 7.5 (6.7–8.5)	0.5	5.7 (4.7–6.7)	0.7