Syngnathus chihiroe, Matsunuma, Mizuki, 2017

Matsunuma, Mizuki, 2017, Syngnathus chihiroe, a new species of pipefish (Syngnathidae) from southern Japan, Zootaxa 4232 (3), pp. 385-396 : 386-395

Syngnathus chihiroe sp. nov.

English name: Deepwater Pipefish Standard Japanese name: Chihiro-yōji

Holotype. NSMT-P 106296, female, 92.0 mm SL, Hirase Shoal , southwest of Yakushima Island, Kagoshima Prefecture , Japan ( East China Sea ), 30°02′N, 130°03′E, 160–162 m depth, R/ V Tansei -maru, Cruise KT-93-09, Station YT-16 (2) , 1 m ORI. biol. dredge, 18 June 1993.

Diagnosis. Dorsal-fin rays 38; pectoral-fin rays 17; trunk rings 18; tail rings 40; total rings 58; subdorsal rings 3.25 + 10.0 = 13.25; HL 8.7 in SL (11.5% SL); snout length 2.3 in HL (43.1% HL); snout depth 8.5 in HL (11.7% HL); snout depth 3.7 in snout length (27.2% snout length); anal ring depth 3.2 in HL (31.4% HL); body ridges entirely smooth without serrae or spines.

Description. Meristics and morphometrics shown in Tables 1 –3. Body elongate, tail clearly longer than trunk ( Fig. 1 ); rings bearing dorsal fin not elevated dorsally; 1st trunk ring bearing pectoral fin, clearly longer than 2nd ring. Brood pouch absent. Head small; snout short, moderately deep, not depressed laterally or ventrally ( Figs. 2 A– B). Dermal flaps absent on head and body. Margins of all ring ridges smooth, without serrae or spines. Superior trunk and tail ridges discontinuous, trunk ridge ending near level of last dorsal-fin ray base, tail ridge (= lateral tail ridge) running downward, straight below greater portion of dorsal-fin base, ending below 10th dorsal-fin ray base ( Fig. 2 C–D); inferior trunk ridge confluent with inferior tail ridge; lateral trunk ridge running straight, posteriormost portion canted slightly downward, ending below 12th dorsal-fin ray base; lateral trunk and tail ridges discontinuous.

Holotype

NSMT-P 106296

Dorsal-fin rays 38

Anal-fin rays 3

Pectoral-fin rays 17 on both sides

Caudal-fin rays 10

Trunk rings 18

Tail rings 40

Subdorsal rings 3.25 + 10.0 = 13.25

Standard length (mm) 92.0

% SL % HL in SL in HL Trunk length 29.5 255.8 3.4 0.4 Tail length 59.5 516.2 1.7 0.2 Head length 11.5 — 8.7 — Head width 3.4 29.6 29.4 3.4 Snout length 5.0 43.1 20.2 2.3 Snout depth 1.3 11.7 74.2 8.5 Orbit diameter 2.2 19.2 45.3 5.2 Interorbital width 0.8 7.3 119.4 13.8 Trunk depth 3.7 32.3 26.9 3.1 Trunk width 3.7 31.7 27.4 3.2 Anal ring depth 3.6 31.4 27.7 3.2 Dorsal-fin base length 20.3 175.8 4.9 0.6 Dorsal-fin height 3.1 27.0 32.2 3.7 Anal-fin length 0.7 5.8 150.7 17.4 Pectoral-fin length 2.7 23.3 37.2 4.3 Pectora-fin base length 1.9 16.1 53.8 6.2 Caudal-fin length 3.0 26.1 33.3 3.8 Median dorsal snout ridge very low, continuous, extending posteriorly just in front of anterior margin of orbit, with 2 slight depressions on anterior half and low expansion just in front of orbit but without distinct serrations; lateral aspects of snout smooth, without distinct ridges or spines. Interorbital portion narrow, depressed; dorsal rim of orbit slightly flared laterally, slightly elevated dorsally; supraorbital, frontal and median head ridges low, vestigial. Opercular ridges undeveloped, median ridge incomplete, short, angled dorsally, its length about half orbit diameter; distinct supraopercular ridge absent. Pectoral-fin base slightly protruding laterally, with single short longitudinal ridge on dorsal portion of base.

Dorsal fin height about 80% of trunk depth, its base very long, origin situated on trunk; anal fin present, very small, situated just behind anus; pectoral fin moderately long, its posterior tip reaching posterior margin of 2nd trunk ring when laid along body; caudal fin small, with rounded contour, middle rays not elongate.

Color of preserved specimen. Head and body uniformly creamy-white without markings; pectoral-fin base narrowly margined with brown; all fins semi-translucent.

Distribution. The species is currently known only from the type locality, southwest of Yakushima Island, Kagoshima Prefecture, Japan (East China Sea), in a depth of 160–162 m ( Fig. 3 ).

Etymology. The specific name, chihiroe , is derived from Japanese “chihiro”, meaning great depth, alluding to the depth of capture of the holotype and only known specimen (160–162 m), one of the deepest recorded for any member of the genus ( Table 4 ).

Remarks. The new species, with trunk rings 18, total rings 58; dorsal-fin rays 38, total subdorsal rings 13.25; pectoral-fin rays 17; anal-fin rays 3; caudal-fin rays 10; superior and tail ridges discontinuous, lateral trunk ridge ending near anal ring, inferior trunk and tail ridges continuous ( Fig. 2 C–D); median dorsal snout ridge low, entire ( Fig. 2 A–B); snout without dorsolateral spines or denticulations, a median lateral ridge or spines; median dorsal head ridges not strongly elevated; supraopercular ridge absent; longitudinal opercular ridge incomplete; pectoralfin base not strongly protruding laterally, with single longitudinal ridge; dorsal-fin origin situated at trunk, fin base not elevated; principal body ridges weakly elevated, entirely smooth without spines or prominent denticulations; dermal flaps absent, is assigned to the genus Syngnathus , as these characters conform closely to the diagnostic features of the genus given by Fritzsche (1980) and Dawson (1985). Although brood pouch morphology in males is a diagnostic feature in syngnathids, the holotype of S. chihiroe is female and lacks the brood pouch.

Following Fritzsche (1980), Dawson (1982, 1985, 1986), Paulus (1992), Kuiter (2009), Naseka & Bogutskaya (2009), Eschmeyer et al. (2016), and Kullander (2016), 34 nominal species of Syngnathus are regarded here as valid. Comparisons of selected meristic characters of S. chihiroe and congeners are shown in Table 2 . The former can be primarily distinguished from the other species by its generally greater number of pectoral-fin rays, in addition to variable differences in numbers of dorsal-fin rays, tail rings, total rings, subdorsal trunk rings, subdorsal tail rings and total subdorsal rings.

Selected morphometrics of S. chihiroe and other species of Syngnathus (Table 3) show that the former is characterized by a relatively short deep snout compared with some congeners, including S. dawsoni , S. floridae , S. folletti , S. louisianae , S. schlegeli , S. macrophthalmus and S. safina .

Syngnathus schmidti (Black Sea and Sea of Azov), shares similar counts of fin rays and body rings with S. chihiroe , but possesses a longer snout, its length more than half of head length ( Dawson 1982), whereas the latter possesses a shorter snout (length 0.43 times head length). Moreover, S. schmidti clearly differs from S. chihiroe in having the distal margins of the body rings typically with spine-like points in sub-adults and adults ( Dawson 1982), unlike the entirely smooth body rings of S. chihiroe . Syngnathus argentatus (Black Sea) and S. typhle (northeastern Atlantic Ocean) possesses similar meristic counts with S. chihiroe , but have the snout strongly compressed laterally with a highly elevated median dorsal ridge ( Dawson 1982; Amor et al. 2007; Kuiter 2009), features not found in S. chihiroe .

ABLE 2. Comparisons of selecteđ meristics in Syngnathus .

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Dorsal-fin origin situateđ between anterior margin of last trunk ring anđ posterior margin of 2nđ tail ring. Dorsal+fin origin situateđ between anterior margin of last trunk ring anđ miđđle of 1st tail ring.

, A et al., D, E, F, K, anđ P inđicate Artüz, Amor et al., Dawson, Eichwalđ, Fritzsche, Kuiter anđ Paulus, respectively.

TABLE ³. Comparisons of selecteđ morphometrics in Syngnathus .

et al., D, anđ P inđicate Amor et al., Dawson anđ Paulus, respectively.

Syngnathus chihiroe can be readily distinguished from S. schlegeli ( Fig. 4 ), the only other recognized northwestern Pacific Ocean congener ( Dawson 1985). [Although Ni & Kwok (1999) noted many literature records of the two Atlantic species, S. acus and S. pelagicus , from Hong Kong, they are most likely misidentifications of S. schlegeli .]. Syngnathus chihiroe differs from the latter in having 17 pectoral-fin rays (vs. 11–15 in the latter), 3.25 subdorsal trunk rings (vs. 1.75–0.0), and a short deep snout, snout length 2.3 in HL and snout depth 3.7 in snout length (vs. 1.6–2.0 and 5.6–11.3, respectively) (data for S. schlegeli taken from Dawson 1985). Comparisons of S. chihiroe with S. schlegeli specimens examined in the present study are shown in Fig. 5 , indicating consistent differences between the two species, viz., snout length 43.1% HL in the former (vs. 48.8–55.7% HL in the latter); snout depth 11.7% HL (vs. 6.3–9.6% HL); anal ring depth 31.4% HL (vs. 11.5–15.6% HL); and snout depth 27.2% snout length (vs. 6.3–9.6% snout length). Contrary to the deep water habitat of the holotype of S. chihiroe , adults of S. schlegeli inhabit seagrasses or algal reefs in coastal inlet and estuarine waters to about 15 m depth ( Kuiter 2009; Senou 2013).

Figures

FIGURE 1. Holotype of Syngnathus chihiroe sp. nov., NSMT-P 106296, female, 92.0 mm SL, southwest of Yakushima Island, Kagoshima Prefecture, Japan. (A) Lateral view of body; (B) lateral and (C) dorsal views of head.

FIGURE 2. Semi-schematic drawings of (A) lateral and (B) dorsal views of head; (C) lateral and (D) dorsolateral views of trunk-tail portion in holotype of Syngnathus chihiroe sp. nov., NSMT-P 106296, 92.0 mm SL. AR: anal ring; DE: dorsal-fin base end; DO: dorsal-fin base origin; ITAR: inferior tail ridge; ITR: inferior trunk ridge; LTAR: lateral tail ridge; LTR: lateral trunk ridge; STAR: superior tail ridge; STR: superior trunk ridge. Dorsal-fin not illustrated in (C) and (D), except for 1 st and last rays in (D). Bars indicate 3 mm.

FIGURE 3. Type locality of Syngnathus chihiroe sp. nov. (red star).

FIGURE 4. Preserved specimen of Syngnathus schlegeli, BSKU 47138 (1 of 9 specimens), 79.4 mm SL, East China Sea.

FIGURE 5. Relationships between snout length (% HL) (A); snout depth (% HL) (B); anal ring depth (% HL); and snout depth (% snout length) (D) to head length (mm) in Syngnathus chihiroe sp. nov. (blue triangle) and S. schlegeli (red circles).

Tables

TABLE 4. Habitats anđ đepth recorđs in Syngnathus.

Species	Habitat	Depth recorđ	References
S. chihiroe sp. nov. S. abaster	offshore waters shallow estuarine waters on sanđ or muđ bottoms	160+162 m đepths to ca. 5 m đepth	This stuđy D (1986); K (2009)
S. acus S. affinis	coastal anđ estuarine waters on sanđ, muđ anđ rough bottoms; common among algae anđ eelgrass ―	to 15 m đepth; an example from ca. 110 m đepth ―	S (1963); D (1986); K (2009)
S. auliscus S. californiensis	eelgrass beđs in bay anđ sloughs; occasionally in floating Sargassum founđ among attacheđ or đrifting kelp ( Macrocystis )	― ―	F (1980) D (1985)
S. caribbaeus	shore water on sanđ bottoms or seagrass beđs	0+5.5 m đepths	D (1985)
S. carinatus S. dawsoni	― coastal waters	― 0.6+6.7 m đepths	D (1982)
S. euchrous S. exilis S. floridae	among eelgrass beđs or loose algae bottom off sanđy beaches, often associateđ with đetacheđ algae ―	― ― 18+55 m đepth, mostly 5 m or less	K (2009) F (1980) D (1982)
S. folletti S. fuscus	algae anđ rock bottoms anđ in estuaries ―	to 30 m đepth to 49.4 m đepth (an example from 182.9 m đepth unconfirmeđ)	K (2009) D (1982)
S. insulae	algae reef; sometimes in floating Sargassum	20+35 m đepths	F (1980)
S. leptorhynchus S. louisianae	among eelgrass in bays anđ estuaries, sometimes founđ in shallow offshore waters ―	― 10+128 m đepths	F (1980) D (1982)
S. macrobrachium	―	―
S. macrophthalmus	―	―
S. makaxi S. pelagicus	bottoms with đense algae or seagrass among floating Sargassum in open oceanic waters	0+1.6 m đepths ―	D (1982) D (1982); K (2009)
S. phlegon	pelagic; typically offshore	at 49 m đepth	D (1986); A (2015)
S. rostellatus S. safina	coastal anđ estuarine waters on sanđy shores among seaweeđ ―	to ca. 18 m đepth, commonly in 0.6+1.8 m 23+33 m đepths	D (1982) P (1992)
S. schlegeli	coastal waters in Zostera seagrasses or algal reefs	to ca. 15 m đepth	D (1985)
S. schmidti S. scovelli	pelagic; near surface of water or in miđwater in open sea coastal waters anđ mainly river đrainages	― ―	D (1982); K (2009) K (2009)
S. springeri S. taenionotus	― coastal waters on shallow muđđy bottom	11+128 m đepths ―	D (1982) D (1982)
S. tenuirostris	inshore algae-weeđ rubble or reefs	to ca. 25 m đepth	K (2009)
S. typhle S. variegatus	coastal anđ estuarine waters; among seaweeđ anđ Zostera rocky bottom with algae	4+20 m đepths 2+40 m đepths	D (1986) K (2009)
S. watermeyeri	tiđal zones of rivers	―	K (2009)
A, D, F, K, P, anđ S	inđicate Artüz, Dawson, Fritzsche, Kuiter, Paulus anđ Smith, respectively.

TABLE 2. (Continueđ)

Species S. makaxi Heralđ & Dawson 1972	Dorsal-fin rays 22+27	Pectoral-fin rays 10+13	Trunk rings 14 or 15	Tail rings 30+32	Total rings 44+47	Subđorsal rings 3.0+1.5 + 3.5+5.5	Subđorsal rings (total) 5.5+6.75	References D (1982)
S. pelagicus Linnaeus 1758	25+34	12+16	15+18	30+34	46+52	3.0+1.0 + 3.75+6.25	5.75+8.5	D (1982)
S. phlegon Risso 1827	38+49	14+16	17+19	47+50	67			D (1986); A (2015)
S. rostellatus Nilsson 1855	33+45	10+13	13+17	37+42			9+12	D (1986)
S. safina Paulus 1992	22 or 23	15 or 16	15	33 or 34		0.33+0.75 + 5.0+5.33		P (1992)
S. schlegeli Kaup 1853	30+47	11+15	18+20	38+46		1.75+0.0 + 6.5+11.0	7.75+12.75	D (1985)
S. schmidti Popov 1928	39+47	15 or 16	16 or 17	36+42			13+15	D (1986)
S. scovelli (Evermann & Kenđall 1896)	25+37	11+17	15+18	28+34	43+51	5.0+1.0 + 3.25+5.5	5.5+9.5	D (1982)
S. springeri Heralđ 1942	32+38	12+14	22+24	34+37	57+61	4.75+3.0 + 3.5+5.0	7.5+9.25	D (1982)
S. taenionotus Canestrini 1871	33+41	11+13	16+18	33+39			8+10	D (1986)
S. tenuirostris Rathke 1836	33+39	12+14	17+19	41+44			8 or 9	D (1986)
S. typhle Linnaeus 1758	28+42	13+17	16+20	31+39	56+58		7+11	D (1986); A et al. (2007)
S. variegatus Pallas 1814 S. watermeyeri Smith 1963	32+42 28+32	12+14 6+8	19+21 16+18	38+41 37+40			7+10 6.75+7.75b	D (1986) D (1985)