Bull. Natl. Mus. Nat. Sci., Ser. A, Suppl. 2, pp. 115–127, March 21, 2008

Cynoglossus ochiaii, a New Tongue Sole from Japan(Pleuronectiformes: Cynoglossidae)
Kōji Yokogawa1, Hiromitsu Endo2 and Hideo Sakaji31

13–5 Higashihama, Tadotsu-cho, Nakatado-gun, Kagawa 764–0016, Japan
E-mail: gargariscus@ybb.ne.jp
2
Laboratory of Marine Biology, Faculty of Science, Kochi University, 2–5–1
Akebono-cho, Kochi 780–8520, Japan
E-mail: endoh@kochi-u.ac.jp
3
National Research Institute of Fisheries Science, Fisheries Research Agency,
2–12–4 Fukuura, Kanazawa, Yokohama, Kanagawa 236–8648, Japan
E-mail: hidekun@fra.affrc.go.jp

Abstract Cynoglossus ochiaii sp. nov. is described on the basis of 28 specimens from Tosa Bay,
off Kochi, and Kagoshima Bay, southern Japan. Formerly regarded as a variation of C. interruptus,
the latter being originally diagnosed as having 2 lateral lines, the new species differs from its congeners by the following combination of characters: 3 continuous ocular side lateral lines; 2 nostrils
on each side; eyes large, without interorbital space; dorsal-fin rays 104–112; anal-fin rays 83–88;
pored scales on dorsolateral line 66–79, midlateral line 67–73, ventrolateral line 38–62, mandibulo-opercular line 15–20 and cephalodorsal line 6–9; scales above dorsolateral line 3–4; scales between dorsolateral and midlateral lines 11–12; supraorbital and midlateral lines present; posterior
marginal flap of each pored lateral-line scale blackish; body uniformly brown; dorsal and anal finsdark brown to blackish, with dappled marks on ocular side, uniformly dense pigmentation on blindside; maximum size about 180 mm in standard length. A bottom-dweller, the new species is foundin depths of ca. 50–220 m around the southern half of Honshu, Shikoku and Kyushu Islands(Japan), and in the East China Sea.
Key words : Cynoglossidae, Cynoglossus, new species, southern Japan, 3 lateral lines

The cynoglossid genus Cynoglossus Hamilton,
1822, including about 50 species, is distributed
from off the Atlantic coast of Africa to Indo-West
Pacific waters (Menon, 1977). Among the 11
species recorded from Japan (Yamada, 2002), thegenko sole, Cynoglossus interruptus Günther,
1880, was recognized on the basis of 2 specimens collected from a Yokohama market (locatedalong Tokyo Bay) (Menon, 1977: 46), and diagnosed by having 2 lateral lines dorsally and medially on the ocular side, the dorsal line being
short, undulating and partly interrupted (Menon,
1977). However, Jordan and Starks (1906)
recorded Japanese “C. interruptus” on the basisof specimens with 3 lateral lines (dorsolateral,
midlateral and ventrolateral; being a supposed
variation), and transferred the species to thegenus Areliscus Jordan and Snyder, 1900 (typespecies: Cynoglossus joyneri Günther, 1878), diagnosed by having 3 lateral lines. Although Wu(1932) recognized 2 lateral lines as distinguishing C. interruptus from other Chinese cynoglossids, Ochiai (1959, 1963) and Menon (1977) followed Jordan and Starks’s view that the 3 lateralline condition was an intra-specific variation.
Subsequently, most ichthyologists have accepted
3 lateral lines as characteristic of C. interruptus(Ochiai, 1965; Yamada, 1986; Amaoka et al.,1995), such being an important character distinguishing the species from other Japanesecynoglossids (e.g., Matsubara, 1955; Yamada,
1993, 2002). On the other hand, Sakamoto(1997) and Sanada (1997) recognized only 2 lateral lines as being diagnostic of C. interruptus.

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K. Yokogawa, H. Endo and H. Sakaji

Furthermore, Shimizu and Watanabe (1997)
questioned the taxonomic treatment of C. interruptus sensu Jordan and Starks (1906), and suggested that the difference in lateral-line numbers
had specific significance.
A recent isozymic analysis by Yokogawa et al.
(2008) revealed that the 2 forms of “C. interruptus” were genetically distinct at the specificlevel. Because 1 of the 2 syntypes (BMNH
1879.5.14.92 and 1890.2.26.146) clearly has 2
lateral lines (Menon, 1977: the former is shown
as “holotype” in fig. 21), we herein describe theform with 3 lateral lines as a new species.
Materials and Methods
Specimens examined in this study are deposited in the following institutions: Laboratory ofMarine Biology, Faculty of Science, Kochi University (BSKU); Faculty of Agriculture, Kyoto
University (FAKU); Laboratory of Marine Zoology, Hokkaido University (HUMZ); Kagoshima
University Museum (KAUM); National Museumof Nature and Science (NSMT, formerly National
Science Museum, Tokyo).
Specimens were collected by the R/V Kotakamaru using an otter trawl in Tosa Bay, Kochi,
during a sampling planned and operated by H.
Honda (FSF: National Research Institute of Far
Sea Fisheries, Fisheries Research Agency), and
H. Sakaji and K. Nashida (NRIFS: National Research Institute of Fisheries Science, Fisheries
Research Agency), under a joint research ventureof NRIFS, NSMT and BSKU from 1997 to 2000
(Shinohara et al., 2001).
Counts and measurements follow Ochiai(1963) and Hubbs and Lagler (1970), in addition
to the following: distance from tip of fleshy snout
to angle of mouth (DSM); distance from tip oflower jaw to angle of mouth (DLM); last 2 raysof dorsal and anal fins counted separately. Lateralline terminology follows Ochiai (1966). Cephaliclateral lines and measurements are shown in Fig.
1. Counts of pored scales and scale rows are as
follows: cephalodorsal line (CDL), dorsolateralline (DLL) and midlateral line (MLL) excluding

scales on the supraorbital commissure (SOC); allpored scales on the ventrolateral (VLL) andmandibulo-opercular lines (MOL) were counted;
SOC scales were counted from the uppermost(between CDL and DLL) to the lowermost [between SOL and preopercular line (POL)], andPOL scales from the uppermost (next to connecting scale between SOL and POL); scales above
DLL (SADLL), between DLL and MLL (DLLMLL), between MLL and VLL (MLL-VLL), andbelow VLL (SBVLL) were counted at the maximum body depth, excluding each lateral line
scale. Standard length and head length are abbreviated as SL and HL, respectively. Fin rays andvertebrae were counted from radiographs.

Fig. 1. Head measurements and lateral-line descriptions for Cynoglossus ochiaii. DLL: Dorsolateral line; MLL: Midlateral line; VLL:
Ventrolateral line; CDL: Cephalodorsal line;
SOL: Supraorbital line; MOL: Mandibulo-opercular line (modified term from Ochiai,1966); SOC: Supraorbital commissure; POL:
Preopercular line; HL: Head length; SNL:
Snout length; UED: Upper eye diameter; LED:
Lower eye diameter; DSM: distance from tipof fleshy snout to angle of mouth; DLM, distance from tip of lower jaw to angle of mouth.

New Tongue Sole from Japan

Cynoglossus ochiaii sp. nov.
(New Japanese name: Oki-genko)(Figs. 2–4, 6A, 6C, 7, Tables 1–3)
Areliscus interruptus (not of Günther): Jordan and Starks,
1906: 240 (in part; description); Hubbs, 1915: 494(list); Jordan and Hubbs, 1925: 302 (list); Okada andMatsubara, 1938: 438 (in part; key); Kuroda, 1951:
390 (in part; list); Matsubara, 1955: 1286 (key);
Tomiyama et al., 1958: 32, pl. 89 (brief description andillustration); Kuroda, 1962: 5 (Izu Peninsula, off Ida
and Toi, depths around 150 and 180 m; brief description).
Cynoglossus interruptus (not of Günther): Ochiai, 1959:
202 [in part; South China Sea to Japan (south of Muroran, Hokkaido), depths around 100 m; description];
Ochiai, 1963: 82, pl. XVIII [in part; Japan (south of
Muroran) to Korea, Phillippines, around 100 m; description and illustration]; Ochiai, 1965: 498, pl. 1402
(in part; brief description); Menon, 1977: 45 (in part;description and synonymy); Ochiai, 1984: 341, pl. 320G (in part; brief description); Kamohara and Okamura,
1985: 63, pl. 134–667 (in part; brief description); Ya-

117

mada, 1986: 412 (in part; brief description and color
photograph); Ochiai, 1987: 929, pl. 3714 (in part; brief
description); Ochiai, 1988: 341, pl. 320-G (in part;
brief description); Abe and Ochiai, 1989: 220 (brief
description and illustration); Yamada, 1993: 1194 (pictorial key; illustration with 3 lateral lines); Yamada etal., 1995: 213, pl. 301 (brief description and illustration with 3 lateral lines); Yamada, 2000: 1391 (pictorial key; illustration with 3 lateral lines); Shinohara etal., 2001: 336 (list; noted that all specimens have 3 lateral lines; central Tosa Bay, ca. 100–150 m); Kim etal., 2001: 290 (in part; brief description); Choi et al.,
2002: 551 (brief description); Yamada, 2002: 1391
(pictorial key; illustration with 3 lateral lines); Youn,
2002: 442, 688 (in part; pictorial key); Kim et al.,2005: 488 (in part; brief description): Ochiai, 2005:
929 (in part; brief description): Yamada et al., 2007:
1158 (in part; brief description and illustration).
Cynoglossus sp.: Yokogawa et al., 2008: 81 (trilinear form
with 3 lateral lines).
Holotype. NSMT-P 76853 (formerly BSKU 74196),
132 mm SL, Tosa Bay, 33°17.2N, 133°36.6E–33°15.5N,

Fig. 2. Cynoglossus ochiaii, holotype in preserved condition, NSMT-P 76853, 132 mm SL, ocular side (above)and blind side (below). Photographed by H. Endo.

118

K. Yokogawa, H. Endo and H. Sakaji

133°36.9E, 129–152 m, R/V Kotaka-maru, 17 Jan. 2005.
Paratypes. 27 specimens from Tosa Bay and
Kagoshima Bay: BSKU 51502, 159 mm SL, Mimase fish
market (bottom trawl), Kochi City, Kochi Prefecture, 8Mar. 2000; BSKU 51840, 136 mm SL, 33°25.4N,
133°34.9E–33°24.8N, 133°34.5E, 56–59 m, R/V Kotaka-maru, 25 Aug. 2000; BSKU 54387, 179 mm SL, Sagafishing port, Kuroshio Town, Kochi Prefecture, 25 Apr.
2002; BSKU 75148, 112 mm SL, BSKU 75149, 111 mm
SL, Kami-kawaguchi fishing port, Kuroshio Town, Kochi
Prefecture, 3 July 2000; BSKU 75580, 116 mm SL,
BSKU 75582, 122 mm SL, 33°20.1N, 133°35.7E–
33°19.7N, 133°34.8E, 100 m, R/V Kotaka-maru, 23
Aug. 2004; BSKU 75979, 132 mm SL, 33°20.6 N,
133°35.6E–33°19.4N, 133°35.0E, 96–105 m, R/V Kotaka-maru, 17 Jan. 2005; BSKU 78261, 84 mm SL,
33°18.4N, 133°31.9E–33°17.6N, 133°30.4E, 99–100
m, R/V Kotaka-maru, 17 June 2004; BSKU 82848, 146
mm SL, Mimase fish market (bottom trawl), Kochi City,
Kochi Prefecture, 14 Dec. 1996; BSKU 82958, 157 mm
SL, Mimase fish market (bottom trawl), Kochi City, Kochi
Prefecture, 5 Oct. 1996; BSKU 85665, 148 mm SL,
33°19.3N, 133°33.3E–33°18.8N, 133°33.0E, 97–99 m,
R/V Kotaka-maru, 7 Sep. 1998; BSKU 85981, 124 mm
SL, Mimase fish market (bottom trawl), Kochi City, Kochi
Prefecture, 17 Dec. 1998; BSKU 89766, 155 mm SL,
BSKU 89767, 163 mm SL, BSKU 89771, 125 mm SL,
BSKU 89772, 151 mm SL, BSKU 89773, 133 mm SL,
Kami-kawaguchi fishing port, Kuroshio Town, Kochi Prefecture, 27 Apr. 2006; KAUM-I. 5870, 143 mm SL,
KAUM-I. 6028, 164 mm SL, KAUM-I. 6031, 133 mm
SL, KAUM-I. 6035, 139 mm SL, KAUM-I. 6036, 153
mm SL, KAUM-I. 6037, 145 mm SL, 31°37.46N,
130°37.11E, 140 m, off west coast of Sakurajima,
Kagoshima Bay, Kagoshima Prefecture, bottom trawl,coll. by Isao Hidaka, 28 July 2007; NSMT-P 57366,
126 mm SL, 33°18.08N, 133°36.76E–33°17.83N,
133°37.19E, 123–127 m, R/V Kotaka-maru, 17 Jan.
1998; NSMT-P 76854 (144 mm SL, formerly BSKU
89769), Kami-kawaguchi fishing port, Kuroshio Town,
Kochi Prefecture, 27 Apr. 2006; NSMT-P 76855 (103 mm
SL, formerly BSKU 89784), Mimase fish market (bottom
trawl), Kochi City, Kochi Prefecture, 5 Apr. 2007.
Non-types. 38 specimens from Tosa Bay, Kagoshima
Bay, and off Shimabara: BSKU 51503, 127 mm SL, Mimase fish market (bottom trawl), Kochi City, Kochi Prefecture, 8 Mar. 2000; BSKU 58738 and 58739, 90–122mm SL, 33°22.8N, 133°33.9E–33°22.7N, 133°34.4E,
74–77 m, R/V Kotaka-maru, 12 Jan. 2001; BSKU 81360(6 specimens), 76–147 mm SL, 33°21.81N, 133°35.85E–
33°20. 89N, 133°34.81E, 86–90 m, R/V Toyohata-maru,
15 Dec. 1992; BSKU 86269–86277, 103–177 mm SL,
collected with the paratype of BSKU 85665; BSKU
91030, 78 mm SL, 33°26.01N, 133°33.62E–33°25.

57N, 133°32.29E, 46–47 m, R/V Toyohata-maru, 15
Dec. 1992; BSKU 91031-91032, 77–80 mm SL,
33°24.51N, 133°34.47E–33°23. 95N, 133°33.21E,
63–64 m, R/V Toyohata-maru, 15 Dec. 1992; NSMT-P
57493, 147 mm SL, 33°16.80N, 133°38.76E–33°16.55N,
133°39.11E, 144–154 m, R/V Kotaka-maru, 8 Dec.
1998; FAKU 4119, 131 mm SL, Kumano Sea, off Kii
Peninsula, Jan. 1937; FAKU M8888, 121 mm SL, Kanaiwa, Ishikawa Prefecture, 26 Oct. 1942; FAKU 11444 and11445, 142–151 mm SL, Okinoshima Islands, Shimane
Prefecture, Nov. 1948; FAKU 13735, 126 mm SL, Kasumi, Hyogo Prefecture, 17 Aug. 1950; FAKU 13938,
127 mm SL, Owase, Mie Prefecture, 20 Sep. 1950;
FAKU 19438, 111 mm SL, FAKU 19446, 111 mm SL,
Nobeoka, Miyazaki Prefecture, 10 Dec. 1952; KAUM-I.
464, 131 mm SL, 31°28.13N, 130°37.82E–31°28.32N,
130°38.31E, 220 m, off Tarumizu, Kagoshima Bay,
Kagoshima Prefecture, bottom trawl, coll. by Katsumi
Nakahata, 15 Mar. 2006; KAUM-I. 5874, 6027, 6029,
6030, 6032, 6034, 121–156 mm SL, collected with theparatypes of KAUM; uncatalogued specimen of Nagasaki
University, 122 mm SL, off Shimabara, Nagasaki Prefecture, ca. 50 m, 20 Dec. 2007.

Diagnosis. A relatively small species of
Cynoglossus with the following combination ofcharacters: 3 lateral lines (dorsolateral, midlateraland ventrolateral) on ocular side; no lateral line
on blind side; cephalodorsal line scales 6–9; dorsolateral line scales 66–79; midlateral line scales
67–73; ventrolateral line scales 38–62; scales
above dorsolateral line 3–4; scales between dorsolateral and midlateral lines 11–12; pored scaleswith well developed blackish posterior flap present on dorsolateral, midlateral, cephalodorsal andmandibulo-opercular lines; eyes contiguous;
mouth without fringe, reaching posteriorly tovertical line at middle of lower eye; 2 nostrils on
ocular side; anterior nostrils developed, tubular;
dorsal and anal fins with dark brown to blackish
dapples; dorsal-fin rays 104–112; anal-fin rays
83–88; caudal-fin rays 10; vertebrae 8–943–455254.
Description. Proportional characters andcounts are shown in Table 1. Body elongate, extremely depressed, highest point at anterior onethird of body length, 27.9–32.2% SL. Entire
body covered with small ctenoid scales. Eyes onleft side of head, moderately large, diameter
about 12.3–17.6% HL. Upper eye slightly anteri-New Tongue Sole from Japan

Fig. 3.

119

Cynoglossus ochiaii, paratype, BSKU 85665, 148 mm SL. Drawn by K. Yokogawa.

or to lower eye. No interorbital space. Snout
rounded, covered with fine scales. Two widelyspaced nostrils on each side: anterior nostril
tubular, in front of lower eye, posterior nostril
lacking tube or flap, immediately between eyes.
Nasal tube on ocular side larger than that on
blind side. Mouth moderately large, upper jaw
mostly covered by large rostral hook. Narrow
bands of small conical teeth on jaws on blindside, teeth absent on ocular side. Posterior margin of operculum almost vertical, with slight indentation on middle portion. Both gill membranes united ventrally, forming shallow fold,free from isthmus. Gill arches lacking rakers.
Anus located near anal-fin origin, opening somewhat posterior to pelvic fin on blind side.
All fins continuous, comprising unbranchedsoft rays. Both pectoral fins absent. Unpaired
pelvic fin with 4 rays, located just below preopercular angle. Dorsal- and anal-fin bases very long.
Dorsal-fin origin at middle of snout, anal-fin origin just posterior to vent.
Lateral-line system on ocular side includes
cephalodorsal, supraorbital, preopercular andmandibulo-opercular lines, and supraorbital commissure on head, and dorsolateral, midlateral andventrolateral lines on trunk (Figs. 1–3).
Cephalodorsal line short, comprising 6–9 pored
scales. Supraorbital and mandibulo-opercularlines somewhat longer than cephalodorsal line.
Dorsolateral line undulating, running posteriorly

along dorsal margin of body to near caudal base.
Midlateral line running almost straight acrosscenter of trunk to caudal base. Ventrolateral line
undulating, running posteriorly along ventral
margin of body and terminating at about 3-quarters length of anal-fin base (Fig. 3). Each pored
scale on dorsolateral, midlateral, cephalodorsal
and mandibulo-opercular lines with a well developed, dark colored (almost black) flap on posterior margin (Fig. 6A, C). No scale row between
rows connected with SOL and MLL (Fig. 7A).
Scales above dorsolateral line 3–4, below ventrolateral line 2–3. No lateral-line systems on blindside.
Color when fresh (Fig. 4). On ocular side,
head and body almost uniformly brown to darkbrown with blackish to dark blueish opercularand abdominal regions, vertical fins dark brown
to blackish with dappled marks. On blind side,
head and body uniformly pale white, vertical finsuniformly dark brown to blackish. Dorsal fin rays
on anterior of head whitish, pelvic fin pale.
Color in alcohol (Fig. 2). On ocular side,
head, body and vertical fins more yellowish thanfresh condition. On blind side, head and bodyuniformly tan with blackish opercular and abdominal region, vertical fins brown to darkishbrown, uniformly and densely pigmented. Peritoneum dark.
Distribution and habitat. Cynoglossus
ochiaii has been recorded from the Pacific coasts

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Table 1. Proportional measurements and counts of Cynoglossus ochiaii, C. interruptus and C. nigropinnatus. Abbreviations of characters given in text and Fig. 1.
C. ochiaii

SL (mm)
As % of SL
Body depth
Dorsal-fin ray length
Anal-fin ray length
Pelvic-fin ray length
Head length (HL)
As % of HL
Snout length
Upper eye diameter
Lower eye diameter
DSM
DLM
Counts
Dorsal-fin rays
Anal-fin rays
Caudal-fin rays
Abdominal vertebrae
Caudal vertebrae
Total vertebrae
Pored scales on
CDL
MOL
SOC
POL
DLL
MLL
VLL
SADLL
DLL-MLL
MLL-VLL
SBVLL

C. interruptus

C. nigropinnatus

Holotype
NSMT-P76853

Paratypes
27 specimens

BSKU
56 specimens

BSKU
15 specimens

132
30.9
7.1
7
6.5
20.2

84–179Range (Mean)
27.9–32.2 (30.4)
6.6–10.0 (8.3)
6.5–9.8 (8.4)
5.2–7.5 (6.2)
18.8–22.5 (20.8)

63–153Range (Mean)
23.7–30.4 (27.2)
5.9–10.7 (7.7)
6.1–10.6 (7.9)
4.0–7.6 (6.0)
17.3–22.1 (20.2)

90–206
Range (Mean)
31.5–36.2 (33.7)
9.6–11.2 (10.3)
9.7–11.1 (10.6)
5.6–6.9 (6.2)
18.0–21.6 (19.7)

31.6
15.8
16.5
48.5
20.7

28.6–36.7 (32.1)
12.3–17.6 (14.7)
13.4–16.5 (14.8)
39.6–50.5 (46.6)
19.0–23.6 (20.8)

25.7–40.0 (31.3)
11.6–20.5 (15.3)
12.0–20.4 (15.3)
35.0–53.2 (42.6)
18.6–26.8 (22.0)

24.6–28.4 (26.4)
15.2–17.8 (16.0)
15.1–18.2 (17.2)
38.2–46.7 (43.6)
21.4–29.4 (25.1)

108
85
10
9
44
53

104–112 (108.4)
83–88 (85.3)
10 (10.0)
8–9 (9.0)
43–45 (43.8)
52–54 (52.8)

105–114 (108.9)
81–91 (84.4)
9–10 (9.9)
8–10 (8.9)
42–45 (43.9)
51–55 (52.8)

107–112 (109.7)
86–90 (87.7)
9–10 (9.9)
9 (9.0)44–46 (45.0)
53–55 (54.0)

7
6
11
4
70
69
41
3
12
12
3

6–9
15–20
10–11
4–7
66–79
67–73
38–62
3–4
11–12
10–13
2–3

0–7
12–18
9–16
4–7
18–38
60–75
none
2–3
10–12

14–15
18–21
10–11
6–10
99–113
69–75
98–104
7–8
11
11–12
6–7

of Honshu, Shikoku and Kyushu Islands, including Owase (Mie), Kumano Sea (off the East ofKii Peninsula), Tosa Bay (off Kochi), Nobeoka(Miyazaki), Kagoshima Bay (Kagoshima),
Shimabara (Nagasaki), and from the Sea ofJapan, including Kanaiwa (Ishikawa), Kasumi(Hyogo) and Okinoshima Islands (Shimane). It isapparently distributed from southern Japan,
southward to the East China Sea, in depths of ca.
50–220 m (Ochiai, 1959, 1963; Kuroda, 1962;
Shinohara et al., 2001; Yamada et al., 2007; thisstudy). In Tosa Bay, specimens were trawledfrom sandy or mud-sandy bottoms in depths of
46–154 m. In Kagoshima Bay, 1 specimen wascollected from 220 m deep.

Etymology. The new species is named after
Dr. Akira Ochiai, Emeritus Professor of Kochi
University, for his great contributions to the taxonomy of Japanese cynoglossids. On the other
hand, the new Japanese name “Oki-genko” indicates its deeper range (“oki” meaning “offshore”)
in comparison with that of “Genko” (Japanesename of C. interruptus, occurring near shore).
Remarks. In his systematic monograph ofCynoglossus, Menon (1977) included “C. interruptus”, including Cynoglossus nigropinnatus
Ochiai, 1963 as a junior synonym [although now
considered a valid species (Yamada, 2002)] andspecimens with 3 lateral lines (now C. ochiaii) as
an intra-specific variation, in the kopsii complex

New Tongue Sole from Japan

121

Fig. 4. Cynoglossus ochiaii, paratype in fresh condition, BSKU 85665, 148 mm SL, ocular side (above) andblind side (below). Photographed by H. Endo.

of the kopsii group, together with Cynoglossus
kopsii (Bleeker, 1851) and Cynoglossus joyneri
Günther, 1878 (the original spelling of “kopsii”,
rather than “kopsi”, is used here as the groupname).
The kopsii group, including 5 species’ complexes [kopsii (3 species), itinus (1), ogilbyi (3),ecaudatus (4) and sealarki (4)], shares “smaller
adult size, large eyes, either contiguous or with avery narrow interorbital space, 2 nostrils, theposterior one occasionally hidden under scales orabsent, short obtusely pointed snout with theangle of the mouth situated nearer to tip of snout
than to branchial opening, 1 to 3 lateral lines onocular side, the dorsolateral and ventrolateral either absent or incomplete, no lateral line on blindside, 10 or 8 rays in the caudal fin, and large
scales” (Menon, 1977: 42). The kopsii complex,
however, differs from other species of the kopsii

group by having the following combination ofcharacters: 10 caudal-fin rays, 7–12 interlinear
scale rows, 2 nostrils on each side and “the dorsolateral line extending to varying distancesalong the dorsal contour (when the ventrolateralline is absent) or with an uninterrupted dorsolateral line (when the ventrolateral line is present)”.
We follow Menon’s classification for these subgroups in Cynoglossus, because the kopsii groupand complex are easily separable from the othergroups and species’ complexes, respectively.
Among the kopsii complex, C. ochiaii closely
resembles C. interruptus in general appearance,
but clearly differs in having a long and continuous DLL with 66–76 pored scales (short and interrupted with 18–38 pored scales in C. interruptus: see “holotype” illustration in Menon,
1977: Fig. 21), VLL present (absent), usually 3
SADLL (usually 2) (Table 2), no scale row be-122

K. Yokogawa, H. Endo and H. Sakaji

tween rows connected with SOL and MLL (onerow) (Fig. 7), 6–9 (mean 7.2, n14) CDL scales(0–7, mean 2.7, n22), 15–20 MOL scales(12–18), posterior margin of pored scales on
DLL, MLL, CDL and MOL with blackish, welldeveloped flap (without flap) (Fig. 6), body uniformly dark brown on ocular side (usually lightbrown with brown dapples), uniformly whitishon blind side (usually white with somewhat orange regions near dorsal and anal-fin bases whenfresh), dorsal and anal fins dark brown to blackish with dappled marks on ocular side and finmembranes uniformly densely pigmented onblind side (blackish marks on fin rays, fin membranes mostly translucent on ocular side, blindside pigmentation sparse or absent) (Figs. 4, 5).
In addition, the body depth of C. ochiaii is somewhat greater than that of C. interruptus(27.9–32.2 vs. 23.7–30.4% SL) and scales of theformer seemed to be the more deciduous.
On the other hand, C. ochiaii is easily separable from C. nigropinnatus, as follows: lower

body depth 27.9–32.2% SL (31.5–36.2 in C. nigropinnatus), anterior nostril on blind side tubular and well developed (rudimentary), snout
moderately long, its length 28.6–36.7% HL(short, 24.6–28.4), 3–4 SADLL (7–8), bodybrown (blackish-brown), dorsal and anal finsdark brown with dappled marks (uniformly
blackish).
Cynoglossus ochiaii is also clearly distinguished from C. kopsii by having a long and continuous VLL (if present, extending to a varying
degree in C. kopsii; lacking in NSMT-P 68318)
and the body uniformly colored on the ocularside (with irregular darker spots), and from C.
joyneri by having large eyes (diameter
Table 2. Scale counts above dorsolateral line of 2
Cynoglossus species.
Scales2

3

4

C. ochiaii
C. interruptus

45
6

3

41

Fig. 5. Cynoglossus interruptus in fresh condition, BSKU 93226, 114 mm SL, ocular side (above) and blind side
(below). Photographed by H. Endo.

New Tongue Sole from Japan

12.3–16.7% HL) without an interorbital space(small with narrow interorbital space in C.
joyneri; upper and lower eyes 6.4 and 7.3% HL,
respectively, in BSKU 62474), and the mouth
angle on the ocular side reaching posteriorly to avertical through the middle of the lower eye (to avertical through the posterior eye margin).
In some Cynoglossus species, differences inlateral-line numbers and conditions on the ocularside have been regarded as intra-specific variations (Ochiai, 1959, 1963, 1966; Menon, 1977).
However, in the kopsii complex, the present example of “C. interruptus” suggests that C. kopsii,
which has similar lateral-line variations, may also
involve more than 1 species (Menon, 1977: fig.
20).
Most previous records and descriptions of “C.
interruptus” have included those of material now
referable to C. ochiaii (e.g., Ochiai, 1963, 1984;
Yamada, 2002). Among them, some have included diagnostic characters of both species, in addition to a color photograph or illustration of C. interruptus (Ochiai, 1984, 2005; Amaoka et al.,
1995; Yamada et al., 2007). Thus, the distribution of each species based on such reports is uncertain. Our reexamination of some FAKU specimens of “C. interruptus” used by Ochiai (1959,
1963), excluding those from Tosa Bay, revealed
that C. ochiaii has also been collected from off
the Pacific coasts of Honshu and Kyushu Islands[Owase (Mie), Kumano Sea (off the east of Kii
Peninsula) and Nobeoka (Miyazaki)], and fromthe Sea of Japan [Kanaiwa (Ishikawa), Kasumi(Hyogo), and Okinoshima Islands (Shimane)].
However, Ochiai’s specimens from Muroran(Southern-east of Hokkaido) are now missing (Y.
Kai, pers. com.). On the other hand, the localities
of Ochiai’s specimens re-identified here as C. interruptus were as follows: Pacific coasts of Honshu [Choshi (Chiba), Miya (Aichi), and Daiozaki and Owase (Mie)], and the Sea of Japan[Maizuru, (Kyoto) and Hofu (Yamaguchi)]. Although Yamada et al. (2007) gathered various biological and fisheries research data for “C. interruptus”, including C. ochiaii, in the East China
Sea, Tosa Bay and Seto Inland Sea off Yam-

123

Fig. 6. Pored scales on dorsolateral line (DLL, A,
B) and midlateral line (MLL, C, D) of two
Cynoglossus species. A, C: C. ochiaii, holotype, NSMT-P 76853; B, D: C. interruptus,
BSKU 39265. Photographed by H. Endo.

aguchi, and noted that “C. interruptus” was distributed widely on the continental shelf of theEast China Sea, precise localities and ranges of
C. ochiaii could not be determined from theirdata. One specimen (HUMZ 108928) of C. interruptus collected from 105 m in the East China
Sea was the deepest record for the species.
Kim and Choi (1994) reported “C. interruptus” from Korean waters, on the basis of collected specimens, noting that the dorsolateral line
was interrupted at mid-body and that the ventro-

124

K. Yokogawa, H. Endo and H. Sakaji
Table 3. Cynoglossus specimens collected from
central Tosa Bay during 4 tows of the RV Toyohata-maru on 15 December 1992 and 1 tow (*)
of the RV Kotaka-maru on 12 January 2001.
Depths (m)C. ochiaii
C. interruptus

Fig. 7. Squamation of scale rows connected withsupraorbital line (SOL, light gray) and midlateral line (MLL, dark gray). A: C. ochiaii; B:
C. interruptus. Drawn by K. Yokogawa.

lateral line was unclear. Kim et al. (2001) also
described “C. interruptus” from Korean waters,
having 3–4 SADLL, a color photograph of 1
specimen confirming its identity as true C. interruptus. However, it remains unclear as to whether
or not these specimens also included C. ochiaii.
Although the latter probably abounds in the East
China Sea (Yamada et al., 2007), its occurrencein Korean waters needs confirmation.
Concerning the occurrence of C. ochiaii
around Taiwan, we were unable to find any published records of “C. interruptus” with 3 laterallines (e.g., Chen and Weng, 1965; Shen, 1967,1993). Among 3 HUMZ specimens collectedfrom Ta-Shih, northern-east part of Taiwan,
HUMZ 10771 may be an example of C. ochiaii,
having 3 lateral lines and a darkish body and fins,but its very poor condition prevented conclusive
identification.
According to research data held by NRIFS,“C. interruptus” has been collected from depths

29–30 46–47 63–64 74–77* 86–90
5

1
7

2
7

2
1

6

of 10–145 m in Tosa Bay, off Kochi (Yamada etal., 2007). On the basis of the specimens examined herein, C. ochiaii occurs between depths of
46–154 m, being plentiful around 100 m. On theother hand, C. interruptus was generally obtained
from shallower than 50 m depth (ca. 10–50 m),
although a single specimen was caught between
74–77 m (BSKU 58740: together with 2 of C.
ochiaii: BSKU 58738 and 58739) and 7 between
63–64 m (BSKU 81378) (Table 3). These indicate that the ranges of the 2 species overlap in
depths of about 45–80 m in Tosa Bay. Other reliable data of the present materials indicates that
C. interruptus also inhabits shallower ranges in
the Seto Inland Sea and Tokyo Bay (ca. 20–30m). In the East China Sea, Yamada et al. (2007)
noted that “C. interruptus” was trawled in depths
between 50–147 m. Although 1 specimen of C.
interruptus (HUMZ 108923) was collected at
105 m (north of the Okinawa Trough), any overlap of the ranges of these 2 species in the East
China Sea is still uncertain. However, C. ochiaii
in that area probably occurs over a deeper range
than C. interruptus, as it does in Tosa Bay, thedifference in preferred habitats likely being related to the ecological divergence of the two
species.
Comparative materials. Cynoglossus interruptus(95 specimens): BSKU 39265, 115 mm SL, Tosa Bay:
BSKU 58740, 101 mm SL, same data as BSKU
58738–58739 (C. ochiaii); BSKU 81378 (7), 89–102 mm
SL, same data as BSKU 91031–91032 (C. ochiaii);
BSKU 81379 (7), 84–100 mm SL, same data as BSKU
91030 (C. ochiaii); BSKU 89574–89578 (5), 106–139mm SL, Tokyo Bay, off Yokohama; BSKU 89579–
89590 (12), 99–142 mm SL, Tokyo Bay, off Yokohama;
BSKU 89739–89744 (6), 62–149 mm SL, Seto InlandSea, off Marugame, Kagawa; BSKU 89877–89910 (34),
65–116 mm SL, Tosa Bay; BSKU 91029 (5), 84–103 mm

New Tongue Sole from JapanSL, 33°27.03N, 133°32.21E–33°27. 66N, 133°33.53E,
30–29 m, R/V Toyohata-maru, 15 Dec. 1992; BSKU
93226, 114 mm SL, Seto Inland Sea, off Marugame, Kagawa; FAKU M7895, 25570, 25572, 116–134 mm SL,
Choshi, Chiba; FAKU 12589, 12623, 100 mm SL, Hofu,
Yamaguchi; FAKU 12722, 108 mm SL, Maizuru, Kyoto;
FAKU 13943, 97 mm SL, Owase, Mie; FAKU 16826,
16827, 16837, 65–110 mm SL, Osaka Bay; FAKU 17265,
20540, 83–92 mm SL, Miya, Aichi; FAKU 19764, 103
mm SL, Daio-zaki, Mie; HUMZ 107802, 107803, 89–114mm SL, Ta-Shih, Taiwan; HUMZ 108928, 91 mm SL,
East China Sea, 30°30.30N, 127°09.32E, 105 m, 21 Nov.
1985. Cynoglossus joyneri (1): BSKU 62474, 209 mm SL,
Tosa Bay. Cynoglossus nigropinnatus (18, all from Tosa
Bay): BSKU 11796, 36895, 39423, 39583, 39969, 51810,
53877, 53878, 53879, 63645, 67392–67394 (3), 74840–
74841 (2), 75628, 78263, 90–206 mm SL. Cynoglossus
kopsii (2): NSMT-P 68318, 104 mm SL, Vietnam.
Cynoglossus sp.: HUMZ 10771, 117 mm SL, Ta-Shih,
Taiwan.

Acknowledgments
We are most grateful to Dr. Akira Ochiai (Professor Emeritus, Kochi University) for supporting our study and Drs. Keiichi Matsuura (NSMT)and Seishi Kimura (Fisheries Research Laboratory, Mie University) for their efforts in preparing
this supplement. We also give special thanks to
the following: Dr. Hitoshi Honda (FSF), Mr.
Kazuya Nashida, and the captain and crews of
R/V Kotaka-maru (NRIFS), Drs. Atsuko Yamaguchi and Gen Kume (Faculty of Fisheries, Nagasaki University), Drs. Yoshihiko Machida andKunio Sasaki (BSKU), and Osamu Okamura(Professor Emeritus, Kochi University) for assistance in collecting specimens; Drs. Gento Shinohara and Masanori Nakae (NSMT), Hisashi Imamura (HUMZ), Yoshiaki Kai (FAKU) and Hiroyuki Motomura (KAUM) for specimen loans;
Drs. Koichi Hoshino (Seikai National Fisheries
Research Institute), Yohko Takata (NSMT) and
Chung-Bae Kang (Pukyong National University,
Korea) for providing literature; and Mr. Naohide
Nakayama and Ms. Eri Katayama (BSKU) for
preparing many radiographs. We also thank Dr.
Graham S. Hardy (Ngunguru, New Zealand) forchecking the English text.

125

Literature Cited
Abe, T. and A. Ochiai. 1989. Keys to the Japanese Fishes
Fully Illustrated in Colors. Vol. 3. Hokuryukan, Tokyo.
315 pp. (In Japanese.)
Amaoka, K., K. Nakaya and M. Yabe. 1995. The Fishes ofNorthern Japan. North Japan Ocean Center, Sapporo.
391 pp. (In Japanese.)
Bleeker, P. 1851. Bijdrage tot de kennis der ichthyologische fauna van Riouw. Natuurkundig Tijdschrift voor
Nederlandsch-Indië, 2: 469–497.
Chen, J. T. F and H. T. C. Wang. 1965. A review of theflatfishes of Taiwan. Tunghai University, Biological
Bulletin, 25, 27: 1–103.
Choi, Y., J.-H. Kim and J.-Y. Park. 2002. Marine Fishes of
Korea. Kyo-Hak Publishing, Seoul. 647 pp. (In Korean.)Günther, A. 1878. Notes on a collection of Japanese seafishes. Annals and Magazin of Natural History, Ser. 5,
1(6): 485–487.
Günther, A. 1880. Report on the Shore Fishes Procured
during the Voyage of H.M.S. “Challenger.” Report on
the Scientific Results of the Voyage of H.M.S. “Challenger” in the Years, Zoology, 1(6): 1–82, pls. 1–32.
Hamilton, F. 1822. An Account of the Fishes Found in theRiver Ganges and its Branches. Fishes Ganges, Edinburgh. i–vii405 pp., pls. 1–39.
Hubbs, C. L. 1915. Flounders and soles from Japan collected by the United States Bureau of Fisheries steamer“Albatross” in 1906. Proceedings of the United States
National Museum, 48 (2082): 449–496, pls. 25–27.
Hubbs, C. L. and K. F. Lagler. 1970. Fishes of the Great
Lakes Region, 3rd edition. University of Michigan
Press, Ann Arbor. 213 pp.
Jordan, D. S. and C. L. Hubbs. 1925. Record of fishes obtained by David Starr Jordan in Japan, 1922. Memoirsof Carnegie Museum, 10(2): 93–346, pls. 5–12.
Jordan, D. S. and O. Snyder. 1900. A list of fishes collected in Japan by Keinosuke Otaki and by the UnitedStates streamer Albatross. Proceedings of the UnitedStates National Museum, 23(1213): 335–380, pls.
9–20.
Jordan, D. S. and E. C. Starks. 1906. A review of theflounders and soles of Japan. Proceedings of the UnitedStates National Museum, 31(1484): 161–246.
Kamohara, T. and O. Okamura. 1985. Colored Illustrations of the Marine Fishes of Japan. Vol. II. Hoikusha
Publishing, Osaka. 161 pp.
Kim, I.-S. and Y. Choi. 1994. A taxonomic revision of thefamily Cynoglossidae (Pisces, Pleuronectiformes) from
Korea. Bulletin of the Korean Fishieries Society, 27:
803–813.
Kim, Y.-U., J.-G. Myoung, Y.-S. Kim, K.-H. Han, C.-B.
Kang and J.-G. Kim. 2001. The Marine Fishes of126

K. Yokogawa, H. Endo and H. Sakaji

Korea. Hanguel, Pusan. 382 pp. (In Korean)Kim, I.-S., Y. Choi, C.-Y. Lee, Y.-J. Lee, B.-J. Kim and J.H. Kim. 2005. Illustrated Book of Korean Fishes. KyoHak Publishig, Seoul. 616 pp. (In Korean.)
Kuroda, N. 1951. A nominal list with distribution of the
fish of Suruga Bay, inclusive of the fresh waters species
found near the coast. Japanese Journal of Ichthyology,
1: 314–338; 376–394.
Kuroda, N. 1962. On the life colors of some fishes -XIV.
Japanese Journal of Ichthyology, 10: 1–5.
Matsubara, K. 1955. Fish Morphology and Hierarchy.
Ishizaki Shoten, Tokyo. Part II, i–v790–1605. (InJapanese.)Menon, A. G. K. 1977. A systematic monograph of the
tongue soles of the genus Cynoglossus HamiltonBuchanan (Pisces: Cynoglossidae). Smithsonian Contributions to Zoology, (238): i–iv1–129.
Ochiai, A. 1959. Morphology, Taxonomy and Ecology ofSoles of Japan. Laboratory of Fisheries, Faculty of Science, Kyoto University, Kyoto. 236 pp., 2 pls. (InJapanese.)
Ochiai, A. 1963. Fauna Japonica Soleina (Pisces). Biogeographical Society of Japan, Tokyo. 115 pp., 24 pls.
Ochiai, A. 1965. Genko, Cynoglossus interruptus. Page
498 in K. Okada, K. Uchida and T. Uchida, eds. New
Illustrated Encyclopedia of the Fauna of Japan. Part 3.
Hokuryukan, Tokyo. (In Japanese.)
Ochiai, A. 1966. Studies on the comparative morphology
and ecology of the Japanese soles. Misaki Marine Biological Institute, Kyoto University, Special Report, (3):
1–97, 2 pls. (In Japanese.)
Ochiai, A. 1984. Cynoglossidae. Pages 341–342 in H.
Masuda, K. Amaoka, C. Araga, T. Uyeno and T. Yoshino, eds. The Fishes of the Japanese Archipelago. English text. Tokai University Press, Tokyo.
Ochiai, A. 1987. Family Cynoglossidae. Pages 927–931 in
T. Abe, ed. Illustrated Fishes of the World in Colour.
Hokuryukan, Tokyo. (In Japanese.)
Ochiai, A. 1988. Cynoglossidae. Pages 341–342 in H.
Masuda, K. Amaoka, C. Araga, T. Uyeno and T. Yoshino, eds. The Fishes of the Japanese Archipelago. 2ndedition. English text. Tokai University Press, Tokyo.
Ochiai, A. 2005. Family Cynoglossidae. Pages 927–931 in
Y. Taki, H. Kohno, K. Sakamoto and K. Hosoya, eds.
Illustrated Fishes of the World in Colour. Revised edition. Hokuryukan, Tokyo. (In Japanese.)
Okada, Y. and K. Matsubara. 1938. Key to the Fishes andFish-like Animals of Japan. Sanseido, Tokyo. ixl585
pp. (In Japanese.)
Sakamoto, K. 1997. Genko, Cynoglossus interruptus.
Page 684 in O. Okamura and K. Amaoka, eds. Sea
Fishes of Japan. Yama-Kei Publishers, Tokyo. (InJapanese.)
Sanada, Y. 1997. Genko, Cynoglossus interruptus. Page

75 in K. Ikehara, ed. Fishes of the Seto Inland Sea.
Fisheries Developing Committee of the Seto InlandSea, Kobe. (In Japanese.)
Shen, S.-C. 1967. Studies on flat-fishes (Pleuronectiformes or Heterosomata) in the adjacent waters ofHong Kong. Quaternary Journal of the Taiwan Museum, 20(1, 2): 150–281.
Shen, S.-C. 1993. Pleuronectiformes. Pages 565–585 in
S.-C. Shen, ed. Fishes of Taiwan. The National Taiwan
University, Taipei.
Shimizu, T. and A. Watanabe. 1997. Seasonal fluctuationof the benthic fish communities in Iyonada, Japan. Bulletin of Ehime Prefectural Fisheries Experimental Station, (6): 11–39. (In Japanese with English abstract.)
Shinohara, G., H. Endo, K. Matsuura, Y. Machida and H.
Honda. 2001. Annotated checklist of the deepwater
fishes from Tosa Bay, Japan. Pages 283–343 in T. Fujita, H. Saito and M. Takeda, eds. Deep-sea Fauna and
Pollutants in Tosa Bay. National Science Museum
Monographs, No. 20.
Tomiyama, I., T. Abe and T. Tokioka. 1958. Encyclopedia
Zoologica Illustrated in Colours. Vol. 2. Hokuryukan,
Tokyo. ixviii39487 pp.
Wu, H.-W. 1932. Contribution à l’etude morphologique,biologique et systématique des poissons hétérosomes(Pisces, Heterosomata) de le Chine. Theses, Universitéde Paris, Paris. 244 pp.
Yamada, U. 1986. Genko, Cynoglossus interruptus
Günther. Page 412 in O. Okamura, ed. Fishes of theEast China Sea and the Yellow Sea. Seikai Regional
Fisheries Research Laboratory, Nagasaki. (In Japanese.)
Yamada, U. 1993. Cynoglossidae. Pages 1191–1195, 1374
in T. Nakabo, ed. Fishes of Japan with Pictorial Keys to
the Species. Tokai University Press, Tokyo. (In Japanese.)
Yamada, U. 2000. Cynoglossidae. Pages 1388–1392, 1639
in T. Nakabo, ed. Fishes of Japan with Pictorial Keys tothe species. 2nd edition. Tokai University Press, Tokyo.
(In Japanese.)
Yamada, U. 2002. Cynoglossidae. Pages 1388–1392, 1630
in T. Nakabo, ed. Fishes of Japan with Pictorial Keys to
the Species. English edition. Tokai University Press,
Tokyo.
Yamada, U., S. Shirai, T. Irie, M. Tokimura, S. Deng, Y.
Zheng, C. Li, Y.-U. Kim and Y.-S. Kim. 1995. Names
and Illustrations of Fishes from the East China Sea andthe Yellow Sea. Oversea Fishery Cooperation Foundation, Tokyo. 288 pp.
Yamada, U., M. Tokimura, H. Horikawa and T. Nakabo.
2007. Fishes and Fisheries of the East China and Yellow Seas. Tokai University Press, Tokyo. i–Ixxiv1263
pp. (In Japanese.)
Yokogawa, K, H. Sakaji, H. Endo and A. Yamaguchi.

New Tongue Sole from Japan
2008. Genetic divergence between two forms of atongue sole, Cynoglossus interruptus. IchthyologicalResearch, 55(1): 78–81.
Youn, C.-H. 2002. Fishes of Korea with Pictorial Key and
Systematic List. Academic Seojeok, Seoul. 747 pp. (In127

Korean.)Manuscript received 27 September 2007; revised 31 January 2008; accepted 15 February 2008.
Associate editor: S. Kimura.