Deep-sea Fauna of the Sea of Japan, edited by T. Fujita, National Museum of Nature and Science Monographs, No. 44,
pp. 205–223, 2014

Ophiuroids (Echinodermata) Collected by the R/V Mizuho-maru fromthe Continental Shelf in the Sea of Japan
Toshihiko Fujita1, Yoshiaki Ishida2 and Yoichi Kogure3
1

Department of Zoology, National Museum of Nature and Science,
4–1–1 Amakubo, Tsukuba-shi, Ibaraki, 305–0005 Japan
E-mail: fujita@kahaku.go.jp
2
2–20–13 Kamiogi, Suginami-ku, Tokyo, 167–0043 Japan
E-mail: y-ishida@msi.biglobe.ne.jp
3
Japan Sea National Fisheries Research Institute, Fisheries Research Agency,
1–5939–22 Suido-cho, Chuo-ku, Niigata-shi, Niigata, 951–8121 Japan
E-mail: seastar@affrc.go.jp

Abstract: We provide a taxonomic list, with taxonomic notes and photographs, of ophiuroids collected by R/V Mizuho-maru from the continental shelf (53–301 m) along the Japanese archipelago in
the Sea of Japan. Our survey identiﬁed 41 species within 22 genera, including 12 species new to the
Sea of Japan.
Key words:

brittle stars, Ophiuroidea, taxonomy.

Introduction
The Sea of Japan has a unique geological history and distinct oceanographic characteristics(see Saito et al., 2014), which affect the composition, abundance and distribution pattern of thespecies which occur there. An extremely cold water mass at depths below the continental shelf
break provides the habitat for a benthic fauna composed primarily of the dominant ophiuroid,
Ophiura sarsii sarsii Lütken, 1855 (Kogure and Nagasawa, 2004). In contrast, the continental
shelf is inﬂuenced by the Tsushima Warm Current, where a wide variety of warm-water species
is expected to be found.
The earliest report of the ophiuroid fauna in the Sea of Japan was that of Duncan (1879),
who reported species obtained from the south and east of the Korean Peninsula. H. L. Clark(1911) described several North Paciﬁc species including several from the Sea of Japan. Some ofthese species, such as Amphiophiura oediplax and Ophiacantha omoplata, have type localities in
the Sea of Japan. Ishida et al. (2001: table 3) reported ophiuroid species from their survey of the
Sea of Japan and summarized past records, including those of H. L. Clark (1911), Djakonov(1954), Irimura (1979, 1991), Irimura et al. (1995), Kogure (1999), Kogure and Hayashi (1998),
Shin (1992, 1995), Shin and Koh (1993), Shin and Rho (1996), Ishida et al. (2001). Ishida et al.
(2001) showed that 91 species were recorded in the sea by the beginning of the 21st century.
Recent taxonomic works have further studied ophiuroids in the Sea of Japan (Kogure, 2001;
Fujita and Kohtsuka, 2003; Fujita et al., 2004; Ishida and Tamura, 2004); however, the areas
investigated were localized. Information on the ophiuroid fauna in this region remains poorly
understood.
As part of the “Research on Deep-Sea Fauna of the Sea of Japan” project, which was under-

206

Toshihiko Fujita, Yoshiaki Ishida and Yoichi Kogure

taken by the National Museum of Nature and Science, we assessed ophiuroid biodiversity along
the Japanese coast in the Sea of Japan. In the present paper, we present a list of collected species.
Materials and Methods
Sampling stations were located on the continental shelf (53–195 m in the depth) with the
exception of one station (St. 04) on the upper slope (301 m in the depth) (Fig. 1). Ophiuroid specimens used in this paper were collected at 29 stations, using either a biological dredge with a
0.5 m or 1 m span width or a beam trawl with a 2 m span width, during two cruises of the R/V
Mizuho-maru of the Japan Sea National Fisheries Research Institute, Fisheries Research Agency
in 2009 and 2010 (Table 1). A Smith-McIntyre grab was used to collect bottom sediment samples. Ophiuroid specimens were ﬁxed in 99% alcohol. Some specimens were dried after ﬁxationfor observation. We have determined ca. 6063 specimens which are treated in this preliminary
paper.
We present a list of collected species with taxonomic remarks, and photographs of fresh
specimens before ﬁxation for each species collected in the study. The identiﬁed specimens aredeposited in the National Museum of Nature and Science (NSMT) in Tsukuba-shi, Japan. In
Material examined, station number (St.), catalog number, number of specimens, and range ofdisk diameter (dd) are shown. The station number is followed by “(SM)” when the specimens
were collected by Smith-McIntyre grab. The detailed data of the stations are shown in Table 1.
Disk diameter was measured with digital calipers only for intact specimens. Depth range indicates the depth range covered by the examined specimens in this study. We follow Smith et al.
(1995) for the classiﬁcation of ophiuroids.

Fig. 1. Sampling stations. Open circles denote the position of sampling stations. Numerals near open circles
denote serial station number. See Table 1 for greater detail.

StationName

MZ10–17
MZ10–14
MZ10–15
MZ10–16
MZ10–11
MZ10–12
MZ10–13
MZ10–07
MZ10–08
MZ10–09
MZ10–10
MZ10–01
MZ10–02
MZ10–03
MZ10–04
MZ10–06
MZ10–05
MZ09–14
MZ09–13
MZ09–12
MZ09–11
MZ09–09
MZ09–10
MZ09–08
MZ09–07
MZ09–06
MZ09–05
MZ09–04
MZ09–03
MZ09–02
MZ09–01

01
02
03
04
05
06
07
08
09
10
11
12*
13*
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31

16 Sep. 201016 Sep. 201016 Sep. 2010
15 Sep. 2010
15 Sep. 2010
15 Sep. 2010
15 Sep. 201017 Sep. 201017 Sep. 201017 Sep. 201017 Sep. 201019 Sep. 201019 Sep. 201019 Sep. 2010
20 Sep. 2010
20 Sep. 2010
20 Sep. 201018 June 200918 June 200918 June 200917 June 200916 June 200916 June 200915 June 200915 June 200914 June 200914 June 200914 June 200914 June 200913 June 200913 June 2009Date

12:53–12:58
07:45–08:05
08:46–09:06
15:24–15:39
07:47–08:04
09:17–09:32
10:25–10:45
12:00–12:20
10:38–10:53
09:12–09:27
07:52–07:55
14:21–14:31
15:28–15:43
17:05–17:20
13:05–13:10
07:53–07:58
10:24–10:29
15:52–16:12
17:40–18:00
14:01–14:21
08:21–08:41
15:13–15:33
12:56–13:16
07:51–08:11
09:40–10:00
16:13–16:33
12:31–12:51
07:52–08:12
09:43–10:03
14:47–15:02
16:45–17:05

Time
41°22.25′N
40°49.32′N
40°50.37′N
40°52.80′N
40°13.06′N
40°13.69′N
40°17.48′N
39°41.67′N
39°42.53′N
39°41.59′N
39°38.40′N
38°57.10′N
38°57.42′N
38°58.09′N
38°55.01′N
39°10.61′N
38°59.04′N
37°38.27′N
37°45.53′N
37°33.67′N
36°32.51′N
35°50.29′N
35°46.00′N
35°24.05′N
35°29.83′N
35°07.09′N
34°37.26′N
34°16.21′N
34°23.94′N
34°17.04′N
34°27.31′N

139°55.64′E
140°10.52′E
140°07.73′E
139°57.61′E
139°51.91′E
139°41.96′E
139°38.49′E
139°54.74′E
139°47.57′E
139°39.69′E
139°31.20′E
139°41.10′E
139°35.84′E
139°32.51′E
139°03.50′E
138°53.47′E
138°39.93′E
137°16.34′E
137°11.52′E
137°03.89′E
136°18.12′E
132°59.00′E
133°14.88′E
132°33.99′E
132°30.77′E
131°07.10′E
131°02.47′E
130°46.88′E
130°42.22′E
129°44.12′E
129°36.28′E

Start position
41°22.22′N
40°49.58′N
40°50.60′N
40°52.69′N
40°12.84′N
40°14.17′N
40°17.98′N
39°41.37′N
39°42.96′N
39°41.40′N
39°38.43′N
38°56.98′N
38°57.19′N
38°58.35′N
38°54.96′N
39°10.53′N
38°59.03′N
37°38.54′N
37°45.41′N
37°33.81′N
36°32.58′N
35°50.31′N
35°45.96′N
35°24.30′N
35°30.17′N
35°07.38′N
34°37.61′N
34°16.00′N
34°24.27′N
34°17.48′N
34°26.98′N

139°55.77′E
140°10.97′E
140°08.18′E
139°57.41′E
139°51.48′E
139°42.00′E
139°38.11′E
139°54.76′E
139°47.27′E
139°39.94′E
139°31.26′E
139°40.96′E
139°35.66′E
139°32.70′E
139°03.44′E
138°53.51′E
138°39.88′E
137°16.27′E
137°11.88′E
137°04.20′E
136°18.60′E
132°59.21′E
133°15.18′E
132°33.79′E
132°30.65′E
131°07.35′E
131°02.68′E
130°46.60′E
130°42.71′E
129°44.45′E
129°35.85′E

End position
124–126
53–54
98–99
301
60–62
93–94
160–169
61
99
192–195
152
57–58
98–99
182–185
160–161
168–170148
97–99
117–121
90–91
96–10098
73
96–97
145–146123
100–101
83–84
97
105
99–100Depth (m)
8.06
25.97
16.96
2.33
23.83
17.34
9.69
25.77
15.69
8.71
11.37
22.28
17.96
4.34
10.04
5.42
5.28
11.74
12.75
12.97
14.78
16.42
17.55
17.84
6.90
17.01
18.23
18.60
17.89
16.38
15.58

Bottomtemperature
(°C)
34.10
33.19
34.24
33.99
33.63
34.30
34.14
33.55
34.32
34.09
34.19
33.86
33.89
33.99
34.11
34.05
34.02
34.20
34.28
34.30
34.36
34.40
34.41
34.41
34.19
34.30
34.39
34.41
34.43
34.23
34.15

Bottomsalinity
(PSU)
1m
2m
2m
2m
2m
2m
2m
2m
2m
2m
1m
2m
2m
2m
0.5 m
0.5 m
0.5 m
2m
2m
2m
2m
2m
2m
2m
2m
2m
2m
2m
2m
2m
2m

Gear

Station list. Abbreviations for collecting gears: 1 m, biological dredge of 1 m span; 2 m, beam trawl of 2 m span; 0.5 m, biological dredge of 0.5 m span. *These stations are notincluded in the material examined in this study.

Serial St.
No.

Table 1.

Ophiuroids of the Sea of Japan
207

208

Toshihiko Fujita, Yoshiaki Ishida and Yoichi Kogure

Species List
Forty-one species in 22 genera representing 9 families are presented herein. Among them, thefollowing 12 species were new to the Sea of Japan, which were not listed by Ishida et al. (2001:
table 3): Astrochele laevis, Astrothrombus chrysanthi ornatus, Ophiostyracium trachyacanthum,
Ophiosemnotes tylota, Ophioleuce seminudum, Amphioplus (Amphioplus) rhadinobrachius,
Amphipholis sobrina, Amphiura (Amphiura) euopla, Amphiura (Amphiura) iridoides, Amphiura(Fellaria) ecnomiotata, Amphiura (Ophiopeltis) aestuarii, Ophiopenia tetracantha.
Family Gorgonocephalidae Ljungman, 1867
Astrochele laevis H. L. Clark, 1911
(Fig. 2A–B)
Material examined. St. 01, NSMT E-7210, 4 specimens, dd 7.1–10.3 mm, NSMT E-7211, 4
specimens, dd 4.5–6.9 mm.
Depth range. 124–126 m.
Remarks. Astrochele paciﬁca has also been reported from Japanese waters recently. Astrochele
species are distinguished by dermal ossicle morphology (Okanishi et al., 2011).
Astrodendrum sagaminum (Döderlein, 1902)(Fig. 2C–D)
Material examined. St. 01, NSMT E-7212, 3 specimens, dd 3.3–8.9 mm.
Depth range. 124–126 m.
Remarks. Only small-sized specimens were collected. Disk diameter of the present species
reaches 70 mm (Irimura, 1991).
Astrothrombus chrysanthi ornatus Mortensen, 1933
(Fig. 2E)
Material examined. St. 01, NSMT E-7213, 1 specimen, dd 3.6 mm.
Depth range. 124–126 m.
Remarks. Astrothrombus chrysanthi ornatus was described by Mortensen (1933) as a new variety. Further studies using more material are required to clarify its status.
Family Ophiomyxidae Ljungman, 1867
Ophiomyxa australis Lütken, 1869
Material examined. St. 15, NSMT E-7214, 2 specimens, dd 3.8–18.0 mm.
Depth range. 160–161 m.
Ophiostyracium trachyacanthum H. L. Clark, 1911
(Fig. 2F–G)
Material examined. St. 20, NSMT E-7215, 1 specimen, dd 1.5 mm; St. 26, NSMT E-7216, 1
specimen, dd 2.3 mm.
Depth range. 90–123 m.
Remarks. Only small-sized specimens were collected. The holotype of the present species is
6 mm in dd collected from off Yakushima Island, in the East China Sea (H. L. Clark, 1911).

Ophiuroids of the Sea of Japan

209

Fig. 2. Gorgonocephalidae, Ophiomyxidae, Ophiacanthidae. A–B, Astroschele laevis (NSMT E-7210, dd
10.3 mm); C–D, Astrodendrum sagaminum (NSMT E-7212, dd 8.9 mm); E, Astrothrombus chrysanthi ornatus
attaching to a gorgonacean colony (NSMT E-7213, dd 3.6 mm); F–G, Ophiostyracium trachyacanthum(NSMT E-7216, dd 2.3 mm); H–I, Ophiosemnotes tylota (NSMT E-7222, dd 6.4 mm). Scale bars. 5 mm(A–D), 2 mm (E-I).

210

Toshihiko Fujita, Yoshiaki Ishida and Yoichi Kogure

Family Ophiacanthidae Ljungman, 1867
Ophiacantha adiaphora H. L. Clark, 1911
Material examined. St. 16, NSMT E-7217, 1 specimen, dd 5.8 mm, NSMT E-7218, 2 specimens, dd 2.7–4.3 mm.
Depth range. 168–170 m.
Ophiacantha omoplata H. L. Clark, 1911
Material examined. St. 01, NSMT E-7219, 1 specimen, dd 3.7 mm; St. 16, NSMT E-7220, 3
specimens, dd 7.3–9.5 mm, NSMT E-7221, 3 specimens, dd 5.1–10.1 mm.
Depth range. 124–170 m.
Ophiosemnotes tylota (H. L. Clark, 1911)(Fig. 2H–I)
Material examined. St. 01, NSMT E-7222, 1 specimen, dd 6.4 mm, NSMT E-7223, 20 specimens, dd 2.9–7.9 mm, NSMT E-7224, 2 specimens, dd 1.7–3.2 mm, NSMT E-7225, 3 specimens,
dd 1.6–7.7 mm.
Depth range. 124–126 m.
Remarks. The present specimens have granule-like short spines on the disk. The scales on thedisk are visible.
Family Ophiuridae Müller & Troschel, 1840
Amphiophiura megapoma (H. L. Clark, 1911)(Fig. 3A–B)
Material examined. St. 01, NSMT E-7226, 1 specimen, dd 7.9 mm, NSMT E-7227, 1 specimen, dd 14.9 mm, NSMT E-7228, 2 specimens, dd 14.0–14.0 mm, NSMT E-7229, 6 specimens,
dd 1.7–6.9 mm; St. 16, NSMT E-7230, 1 specimen, dd 15.1 mm; St. 17, NSMT E-7231, 2 specimens, dd 9.5–11.1 mm.
Depth range. 124–170 m.
Ophiochalcis aspera Koehler, 1931
Material examined. St. 21, NSMT E-7232, 1 specimen, dd 4.6 mm.
Depth range. 96–100 m.
Ophiura kinbergi (Ljungman, 1866)(Fig. 3C–D)
Material examined. St. 02, NSMT E-7233, 13 specimens, dd 2.2–3.9 mm; St. 05, NSMT
E-7234, 63 specimens, dd 1.3–3.3 mm; St. 08, NSMT E-7235, 124 specimens, dd 1.1–3.8 mm;
St. 18, NSMT E-7236, 4 specimens, dd 3.8–5.1 mm; St. 18 (SM), NSMT E-7237, 6 specimens,
dd 0.4–3.4 mm; St. 19, NSMT E-7238, 4 specimens, dd 2.4–4.6 mm; St. 20, NSMT E-7239, 14
specimens, dd 2.3–5.2 mm; St. 20 (SM), NSMT E-7240, 6 specimens, dd 0.4–0.6 mm; St. 21,
NSMT E-7241, 22 specimens, dd 2.2–5.6 mm, NSMT E-7242, 9 specimens, dd 2.5–4.2 mm; St.
21 (SM), NSMT E-7243, 6 specimens, dd 0.4–1.5 mm; St. 22, NSMT E-7244, 1 specimen, dd
2.8 mm, NSMT E-7245, 252 specimens, dd 1.6–7.4 mm, NSMT E-7246, 19 specimens, dd 0.7–
3.5 mm; St. 22 (SM), NSMT E-7247, 3 specimens, dd 0.7–3.8 mm; St. 23, NSMT E-7248, 158
specimens, dd 1.5–8.9 mm, NSMT E-7249, 141 specimens, dd 0.5–5.1 mm; St. 23 (SM), NSMTOphiuroids of the Sea of Japan

211

Fig. 3. Ophiuridae (Ophiurinae). A–B, Amphiophiura megapoma (NSMT E-7227, dd 14.9 mm); C–D, Ophiurakinbergi (NSMT E-7259, dd 8.1 mm); E-F, Ophiura sarsii sarsii (NSMT E-7275, dd 17.5 mm); G–H, Ophiura
sarsii vadicola (NSMT E-7286, dd 14.6 mm). Scale bars. 10 mm (A–B), 5 mm (C–H).

E-7250, 1 specimen, dd 0.7 mm; St. 24, NSMT E-7251, 497 specimens, dd 1.8–10.1 mm, NSMT
E-7252, 88 specimens, dd 0.7–3.0 mm; St. 25, NSMT E-7253, 4 specimens, dd 0.7–3.6 mm; St.
26, NSMT E-7254, 36 specimens, dd 1.7–7.8 mm; St. 27, NSMT E-7255, 279 specimens, dd
2.0–10.1 mm, NSMT E-7256, 1045 specimens, dd 0.7–8.5 mm; St. 27 (SM), NSMT E-7257, 2
specimens, dd 5.4–7.2 mm; St. 28, NSMT E-7258, 109 specimens, dd 2.2–9.6 mm, NSMT
E-7259, 1 specimen, dd 8.1 mm, NSMT E-7260, 492 specimens, dd 1.9–10.0 mm, NSMT
E-7261, 151 specimens, dd 1.1–9.0 mm, NSMT E-7262, 6 specimens, dd 0.6–1.2 mm; St. 29,
NSMT E-7263, 3 specimens, dd 3.7–7.8 mm; St. 29 (SM), NSMT E-7264, 4 specimens, dd 0.5–
2.2 mm; St. 30, NSMT E-7265, 5 specimens, dd 2.8–4.2 mm, NSMT E-7266, 65 specimens, dd
1.7–5.5 mm, NSMT E-7267, 1 specimen, dd 4.3 mm, NSMT E-7268, 5 specimens, dd 1.9–
3.2 mm; St. 31, NSMT E-7269, 51 specimens, dd 1.3–4.2 mm; St. 31 (SM), NSMT E-7270, 1
specimen, dd 0.6 mm.
Depth range. 53–146 m.
Remarks. Ophiura kinbergi, Ophiura leptoctenia, Ophiura sarsii sarsii, and Ophiura sarsii
vadicola were also collected by the survey. The genus Ophiura is one of the dominant ophiuroids
in the Sea of Japan. The differences between these species were discussed in Fujita et al. (2009).

212

Toshihiko Fujita, Yoshiaki Ishida and Yoichi Kogure

Ophiura leptoctenia H. L. Clark, 1911
Material examined. St. 04, NSMT E-7271, 15 specimens, dd 5.3–7.1 mm.
Depth range. 301 m.
Ophiura sarsii sarsii Lütken, 1855
(Fig. 3E–F)
Material examined. St. 04, NSMT E-7272, 1 specimen, dd 20.1 mm, NSMT E-7273, 62 specimens, dd 8.2–20.6 mm; St. 07, NSMT E-7274, 16 specimens, dd 12.4–22.7 mm; St. 10, NSMT
E-7275, 1 specimen, dd 17.5 mm, NSMT E-7276, 13 specimens, dd 3.3–6.9 mm, NSMT E-7277,
46 specimens, dd 5.4–18.5 mm.
Depth range. 160–301 m.
Ophiura sarsii vadicola Djakonov, 1949
(Fig. 3G–H)
Material examined. St. 01, NSMT E-7278, 1 specimen, dd 17.9 mm; St. 07, NSMT E-7279,
310 specimens, dd 8.6–21.4 mm; St. 14, NSMT E-7281, 513 specimens, dd 3.7–17.9 mm, NSMT
E-7282, 1 specimen, dd 9.0 mm, NSMT E-7283, 11 specimens, dd 2.6–8.0 mm, NSMT E-7284,
100 specimens, dd 4.8–16.5 mm; St. 25, NSMT E-7285, 13 specimens, dd 0.7–2.4 mm, NSMT
E-7286, 5 specimens, dd 3.6–14.6 mm, NSMT E-7287, 29 specimens, dd 4.1–16.3 mm, NSMT
E-7288, 11 specimens, dd 1.9–14.7 mm.
Depth range. 124–185 m.

Fig. 4. Ophiuridae (Ophiurinae). A–B, Stegophiura sladeni (NSMT E-7291, dd 15.0 mm); C–D, Stegophiura
sterea (NSMT E-7317, dd 2.1 mm); E-F, Stegophiura vivipara (NSMT E-7318, dd 7.9 mm). Scale bars. 10 mm(A–B), 2 mm (C–D), 5 mm (E-F).

Ophiuroids of the Sea of Japan

213

Stegophiura sladeni (Duncan, 1879)(Fig. 4A–B)
Material examined. St. 02, NSMT E-7289, 1 specimen, dd 1.5 mm; St. 19, NSMT E-7290, 2
specimens, dd 13.2–13.6 mm, NSMT E-7291, 1 specimen, dd 15.0 mm; St. 20, NSMT E-7292, 2
specimens, dd 1.2–6.0 mm; St. 21, NSMT E-7293, 2 specimens, dd 2.2–15.0 mm, NSMT E-7294,
2 specimens, dd 2.2–4.8 mm; St. 22, NSMT E-7295, 3 specimens, dd 2.8–5.2 mm, NSMT
E-7296, 1 specimen, dd 3.1 mm, NSMT E-7297, 10 specimens, dd 15.9–21.5 mm; St. 23, NSMT
E-7298, 1 specimen, dd 4.9 mm, NSMT E-7299, 2 specimens, dd 4.9–5.5 mm; St. 24, NSMT
E-7300, 76 specimens, dd 2.1–16.4 mm, NSMT E-7301, 15 specimens, dd 2.4–6.7 mm; St. 26,
NSMT E-7302, 3 specimens, dd 1.5–2.7 mm, NSMT E-7303, 1 specimen, dd 17.4 mm, NSMT
E-7304, 1 specimen, dd 16.3 mm; St. 27, NSMT E-7305, 3 specimens, dd 10.6–17.3 mm; St. 28,
NSMT E-7306, 1 specimen, dd 17.0 mm; St. 29, NSMT E-7307, 1 specimen, dd 10.2 mm.
Depth range. 53–123 m.
Stegophiura sterea (H. L. Clark, 1908)(Fig. 4C–D)
Material examined. St. 07, NSMT E-7308, 38 specimens, dd 2.1–14.9 mm, NSMT E-7309, 3
specimens, dd 11.2–14.4 mm; St. 09, NSMT E-7310, 1 specimen, dd 13.5 mm; St. 10, NSMT
E-7311, 3 specimens, dd 14.2–15.1 mm; St. 14, NSMT E-7312, 62 specimens, dd 7.7–16.2 mm,
NSMT E-7313, 2 specimens, dd 7.8–13.5 mm; St. 25, NSMT E-7314, 19 specimens, dd 10.0–
18.7 mm, NSMT E-7315, 1 specimen, dd 17.2 mm, NSMT E-7316, 1 specimen, dd 1.8 mm; St.
26, NSMT E-7317, 1 specimen, dd 2.1 mm.
Depth range. 99–195 m.
Stegophiura vivipara Matsumoto, 1915
(Fig. 4E–F)
Material examined. St. 23, NSMT E-7318, 1 specimen, dd 7.9 mm, NSMT E-7319, 1 specimen, dd 3.5 mm, NSMT E-7320, 2 specimens, dd 4.7–5.6 mm.
Depth range. 73 m.
Ophioleuce seminudum Koehler, 1904
Material examined. St. 30, NSMT E-7321, 1 specimen, dd 6.8 mm.
Depth range. 105 m.
Family Amphiuridae Ljungman, 1867
Amphioplus (Amphioplus) ancistrotus (H. L. Clark, 1911)(Fig. 5A–B)
Material examined. St. 04, NSMT E-7322, 3 specimens, dd 7.2 mm; St. 10, NSMT E-7323, 1
specimen, dd 7.8 mm, NSMT E-7324, 1 specimen, dd 7.9 mm, NSMT E-7325, 1 specimen, dd
5.6 mm, NSMT E-7326, 18 specimens, dd 4.8 mm; St. 14, NSMT E-7327, 1 specimen, dd
6.1 mm, NSMT E-7328, 4 specimens, dd 3.8–7.4 mm; St. 20 (SM), NSMT E-7329, 1 specimen,
dd 8.1 mm.
Depth range. 90–301 m.

214

Toshihiko Fujita, Yoshiaki Ishida and Yoichi Kogure

Fig. 5. Amphiuridae. A–B, Amphioplus (Amphioplus) ancistrotus (NSMT E-7329, dd 8.1 mm); C–D, Amphioplus (Amphioplus) rhadinobrachius (NSMT E-7344, dd 1.9 mm); E–F, Amphioplus (Lymanella) japonicus(NSMT E-7336, dd 4.4 mm); G–H, Amphipholis tetracantha (NSMT E-7356, dd 7.1 mm). Scale bars. 10 mm(A–B), 2 mm (C-D), 5 mm (E–H).

Amphioplus (Amphioplus) rhadinobrachius H. L. Clark, 1911
(Fig. 5C–D)
Material examined. St. 03, NSMT E-7340, 3 specimens, dd 2.2–3.3 mm; St. 06, NSMT
E-7341, 2 specimens; St. 09, NSMT E-7342, 1 specimen, NSMT E-7343, 1 specimen, dd
1.8 mm; St. 31 (SM), NSMT E-7344, 1 specimen, dd 1.9 mm.
Depth range. 93–100 m.

Ophiuroids of the Sea of Japan

215

Remarks. Only small-sized specimens (smaller than 3.3 mm in disk diameter) were collectedwith single tentacle scale. Larger specimens (5–6 mm in disk diameter) have two tentacle scales(H. L. Clark, 1911; Irimura, 1991).
Amphioplus (Lymanella) japonicus (Matsumoto, 1915)(Fig. 5E–F)
Material examined. St. 22, NSMT E-7330, 1 specimen, dd 1.4 mm; St. 24 (SM), NSMT
E-7331, 1 specimen, dd 2.2 mm; St. 24, NSMT E-7332, 1 specimen, dd 1.9 mm; St. 27, NSMT
E-7333, 8 specimens, dd 3.2–4.9 mm; St. 28, NSMT E-7334, 3 specimens, dd 3.3–4.8 mm,
NSMT E-7335, 1 specimen, dd 4.2 mm, NSMT E-7336, 1 specimen, dd 4.4 mm, NSMT E-7337,
136 specimens, dd 1.4–6.8 mm, NSMT E-7338, 53 specimens, dd 2.0–4.8 mm; St. 31, NSMT
E-7339, 2 specimens, dd 1.7–3.1 mm.
Depth range. 83–101 m.
Amphipholis sobrina Matsumoto, 1917
Material examined. St. 01, NSMT E-7345, 1 specimen, dd 2.8 mm; St. 11, NSMT E-7346, 1
specimen, dd 2.1 mm; St. 14, NSMT E-7347, 1 specimen, dd 2.4 mm; St. 16, NSMT E-7348, 18
specimens, dd 1.3–3.9 mm; St. 18, NSMT E-7349, 1 specimen, dd 3.2 mm; St. 20, NSMT
E-7350, 5 specimens, dd 1.9–3.9 mm; St. 20 (SM), NSMT E-7351, 3 specimens, dd 1.9–2.7 mm;
St. 21, NSMT E-7352, 4 specimens, dd 2.4–3.2 mm; St. 30, NSMT E-7353, 1 specimen, dd
3.4 mm; St. 31, NSMT E-7354, 2 specimens, dd 1.8 mm.
Depth range. 90–185 m.
Amphipholis tetracantha Matsumoto, 1941
(Fig. 5G–H)
Material examined. St. 09, NSMT E-7355, 1 specimen, dd 3.3 mm; St. 10, NSMT E-7356, 1
specimen, dd 7.1 mm, NSMT E-7357, 1 specimen, dd 2.6 mm, NSMT E-7358, 3 specimens, dd
3.2–4.3 mm, NSMT E-7359, 32 specimens, dd 3.2–7.7 mm; St. 14, NSMT E-7360, 5 specimens,
dd 3.1–6.3 mm.
Depth range. 99–195 m.
Remarks. Matsumoto (1941) reported that radial shields are about twice as long as wide. Someof the present specimens have shorter radial shields probably because they have been regenerated.
Amphiura (Amphiura) arcystata H. L. Clark, 1911
(Fig. 6A–B)
Material examined. St. 10, NSMT E-7362, 1 specimen, dd 11.5 mm; St. 14, NSMT E-7363, 1
specimen, dd 6.2 mm, NSMT E-7364, 3 specimens, dd 6.6–10.4 mm; St. 25, NSMT E-7365, 1
specimen, dd 11.8 mm, NSMT E-7366, 7 specimens, dd 11.4–15.3 mm, NSMT E-7367, 4 specimens, dd 11.5 mm.
Depth range. 145–195 m.
Remarks. The arms have reddish and whitish-color bands alternatively. The present specimens
have scales only round radial shields. The status of this species was discussed in A. M. Clark(1970).

216

Toshihiko Fujita, Yoshiaki Ishida and Yoichi Kogure

Fig. 6. Amphiuridae. A–B, Amphiura (Amphiura) arcystata (NSMT E-7363, dd 6.2 mm); C–D, Amphiura(Amphiura) digitula (NSMT E-7376, dd 8.4 mm); E-F, Amphiura (Amphiura) euopla (NSMT E-7383, dd
9.2 mm). Scale bars. 10 mm (A, E–F), 2 mm (B–D).

Amphiura (Amphiura) digitula (H. L. Clark, 1911)(Fig. 6C–D)
Material examined. St. 08, NSMT E-7368, 4 specimens, dd 5.2–6.3 mm; St. 20 (SM), NSMT
E-7369, 5 specimens, dd 5.0–6.3 mm; St. 20, NSMT E-7370, 1 specimen, dd 7.2 mm; St. 20(SM), NSMT E-7371, 1 specimen, dd 3.8 mm; St. 22, NSMT E-7372, 1 specimen, dd 4.8 mm; St.
27, NSMT E-7373, 1 specimen, dd 5.5 mm, NSMT E-7374, 1 specimen, dd 3.2 mm; St. 28,
NSMT E-7375, 15 specimens, dd 4.3–8.4 mm, NSMT E-7376, 1 specimen, dd 8.4 mm, NSMT
E-7377, 17 specimens, dd 5.2–5.7 mm, NSMT E-7378, 11 specimens, dd 2.3–4.6 mm; St. 29,
NSMT E-7379, 2 specimens.
Depth range. 61–101 m.

Ophiuroids of the Sea of Japan

217

Amphiura (Amphiura) euopla H. L. Clark, 1911
(Fig. 6E–F)
Material examined. St. 20, NSMT E-7382, 1 specimen, dd 6.0 mm; St. 21 (SM), NSMT
E-7383, 1 specimen, dd 9.2 mm; St. 31, NSMT E-7384, 1 specimen, dd 8.8 mm.
Depth range. 90–100 m.
Amphiura (Amphiura) iridoides Matsumoto, 1917
(Fig. 7A–B)
Material examined. St. 18, NSMT E-7385, 1 specimen, dd 2.5 mm; St. 19 (SM), NSMT
E-7386, 3 specimens, dd 1.1–1.5 mm; St. 20, NSMT E-7387, 1 specimen, dd 4.1 mm; St. 21,
NSMT E-7388, 1 specimen, dd 3.5 mm, NSMT E-7389, 1 specimen, dd 2.1 mm; St. 30, NSMT
E-7390, 1 specimen, dd 3.2 mm.
Depth range. 90–121 m.
Amphiura (Amphiura) koreae Duncan, 1879
Material examined. St. 15, NSMT E-7391, 1 specimen, dd 4.0 mm.
Depth range. 160–161 m.
Amphiura (Amphiura) microdiscoida H. L. Clark, 1915
(Fig. 7C)
Material examined. St. 20, NSMT E-7392, 1 specimen, dd 2.8 mm.
Depth range. 90–91 m.
Remarks. Hemipholis microdiscus Duncan, 1879 was transferred to Amphiura by H. L. Clark(1915) when the name was changed to Amphiura microdiscoida to avoid the homonymy with
Amphiura microdisca Lütken, 1856. Ventral interradial disk has no scale like Amphiura (Amphiura) euopla.
Amphiura (Amphiura) psilopora H. L. Clark, 1911
(Fig. 7D–E)
Material examined. St. 21, NSMT E-7393, 1 specimen, dd 1.9 mm; St. 21 (SM), NSMT
E-7394, 1 specimen, dd 1.8 mm.
Depth range. 96–100 m.
Amphiura (Fellaria) ecnomiotata H. L. Clark, 1911
Material examined. St. 26, NSMT E-7380, 1 specimen, dd 8.4 mm; St. 28, NSMT E-7381, 1
specimen, dd 4.5 mm.
Depth range. 83–123 m.
Amphiura (Ophiopeltis) aestuarii Matsumoto, 1915
Material examined. St. 14, NSMT E-7361, 2 specimens, dd 3.9–4.2 mm.
Depth range. 182–185 m.
Remarks. Most of the tentacle pores bear no tentacle scale, but some pores have single tentacle
scale.

218

Toshihiko Fujita, Yoshiaki Ishida and Yoichi Kogure

Fig. 7. Amphiuridae. A–B, Amphiura (Amphiura) iridoides (NSMT E-7387, dd 4.1 mm); C, Amphiura (Amphiura) microdiscoida (NSMT E-7392, dd 2.8 mm); D–E, Amphiura (Amphiura) psilopora (NSMT E-7394, dd
1.8 mm); F–G, Ophiocentrus koehleri (NSMT E-7396, dd 4.9 mm). Scale bars. 5 mm (A–B, F–G), 2 mm(C–E).

Ophiocentrus koehleri Gislén, 1926
(Fig. 7F–G)
Material examined. St. 27, NSMT E-7395, 1 specimen, dd 3.8 mm, NSMT E-7396, 1 speci-

Ophiuroids of the Sea of Japan219

men, dd 4.9 mm; St. 28, NSMT E-7397, 2 specimens, dd 2.6–6.5 mm, NSMT E-7398, 1 specimen, dd 1.8 mm; St. 31, NSMT E-7399, 5 specimens, dd 2.2–4.3 mm, NSMT E-7400, 1 specimen, dd 8.6 mm.
Depth range. 83–101 m.
Family Ophiotrichidae Ljungman, 1867
Ophiogymna fulgens (Koehler, 1905)(Fig. 8A–B)
Material examined. St. 22, NSMT E-7401, 3 specimens, dd 3.8–7.5 mm, NSMT E-7402, 1
specimen, dd 6.5 mm.
Depth range. 98 m.
Ophiothrix (Ophiothrix) exigua Lyman, 1874
(Fig. 8C–D)
Material examined. St. 02, NSMT E-7403, 1 specimen, dd 2.2 mm; St. 21, NSMT E-7404, 5
specimens, dd 3.2–6.8 mm; St. 22, NSMT E-7405, 2 specimens, dd 2.3–3.9 mm; St. 24, NSMT
E-7406, 1 specimen, dd 7.9 mm; St. 31, NSMT E-7407, 1 specimen, dd 7.8 mm, NSMT E-7408,
1 specimen, dd 7.7 mm, NSMT E-7409, 4 specimens, dd 3.0–5.4 mm.
Depth range. 53–100 m.
Remarks. Differences between Ophiothrix exigua and Ophiothrix panchyendyta are not clear
for smaller individuals, but the sizes of radial shields and disk spines are slightly different (Fujita
and Kohtsuka, 2003). Ophiothrix exigua was collected in shallower depths and O. panchyendyta
in deeper depths.
Ophiothrix (Ophiothrix) panchyendyta H. L. Clark, 1911
(Fig. 8E–F)
Material examined. St. 11, NSMT E-7410, 16 specimens, dd 9.2–18.0 mm, NSMT E-7411, 9
specimens, dd 3.0–8.3 mm; St. 14, NSMT E-7412, 14 specimens, dd 7.5–20.8 mm; St. 15, NSMT
E-7413, 17 specimens, dd 2.2–15.5 mm; St. 16, NSMT E-7414, 2 specimens, dd 4.9–7.5 mm,
NSMT E-7415, 82 specimens, dd 3.7–15.9 mm, NSMT E-7416, 6 specimens, dd 2.2–3.7 mm; St.
17 (SM), NSMT E-7417, 1 specimen, dd 17.6 mm; St. 17, NSMT E-7418, 10 specimens, dd 3.6–
13.7 mm; St. 18, NSMT E-7419, 2 specimens, dd 10.6–17.8 mm, NSMT E-7420, 1 specimen, dd
19.7 mm; St. 19, NSMT E-7421, 1 specimen, dd 12.6 mm; St. 21, NSMT E-7422, 1 specimen, dd
2.6 mm; St. 31, NSMT E-7423, 1 specimen, dd 6.3 mm, NSMT E-7424, 1 specimen, dd 6.5 mm,
NSMT E-7425, 1 specimen, dd 7.0 mm.
Depth range. 96–185 m.
Family Ophiactidae Matsumoto, 1915
Ophiactis plana Lyman, 1869
(Fig. 8G–H)
Material examined. St. 15, NSMT E-7426, 11 specimens, dd 1.1–2.6 mm; St. 15 (SM), NSMT
E-7427, 1 specimen, dd 2.7 mm; St. 16, NSMT E-7428, 1 specimen, dd 3.5 mm, NSMT E-7429,
69 specimens, dd 2.2–5.8 mm; St. 17, NSMT E-7430, 4 specimens, dd 2.2–2.7 mm; St. 20,
NSMT E-7431, 1 specimen, dd 1.9 mm; St. 30, NSMT E-7432, 2 specimens, dd 1.2–1.8 mm.
Depth range. 90–170 m.

220

Toshihiko Fujita, Yoshiaki Ishida and Yoichi Kogure

Fig. 8. Ophiotrichidae, Ophiactidae. A–B, Ophiogymna fulgens (NSMT E-7402, dd 6.5 mm); C–D, Ophiothrix(Ophiothrix) exigua (NSMT E-7407, dd 7.8 mm); E-F, Ophiothrix (Ophiothrix) panchyendyta (NSMT E-7421,
dd 12.6 mm); G–H, Ophactis plana (NSMT E-7431, dd 1.9 mm); I–J, Ophiopholis mirabilis (NSMT E-7444,
dd 9.7 mm). Scale bars. 10 mm (A–B), 2 mm (C–H), 5 mm (I–J).

Ophiopholis japonica Lyman, 1879
Material examined. St. 01, NSMT E-7433, 36 specimens, dd 3.4–12.5 mm; St. 11, NSMT
E-7434, 1 specimen, dd 3.4 mm; St. 14, NSMT E-7435, 1 specimen, dd 12.2 mm; St. 16, NSMT
E-7436, 10 specimens, dd 2.6–4.6 mm, NSMT E-7437, 99 specimens, dd 2.2–13.4 mm, NSMT
E-7438, 2 specimens, dd 7.6–10.7 mm, NSMT E-7440, 25 specimens, dd 1.6–3.7 mm; St. 16(SM), NSMT E-7439, 1 specimen, dd 1.0 mm; St. 17, NSMT E-7441, 1 specimen, dd 5.2 mm,
NSMT E-7442, 1 specimen, dd 9.5 mm.
Depth range. 124–185 m.

Ophiuroids of the Sea of Japan

221

Fig. 9. Ophiodermatidae, Ophiolepididae. A–B, Ophiopsammus anchistus (NSMT E-7466, dd 15.0 mm); C–D,
Ophiopenia tetracantha (NSMT E-7467, dd 3.2 mm). Scale bars. 10 mm (A), 5 mm (B), 2 mm (C–D).

Ophiopholis mirabilis (Duncan, 1879)(Fig. 8I–J)
Material examined. St. 14, NSMT E-7443, 1 specimen, dd 7.5 mm; St. 18, NSMT E-7444, 1
specimen, dd 9.7 mm; St. 19, NSMT E-7445, 1 specimen, dd 5.9 mm; St. 20, NSMT E-7446, 1
specimen, dd 4.8 mm, NSMT E-7447, 1 specimen, dd 6.5 mm; St. 21, NSMT E-7448, 1 specimen, dd 4.5 mm.
Depth range. 90–185 m.
Family Ophiodermatidae Ljungman, 1867
Ophiopsammus anchistus (H. L. Clark, 1911)(Fig. 9A–B)
Material examined. St. 18, NSMT E-7464, 1 specimen, dd 18.2 mm; St. 22, NSMT E-7465, 1
specimen, dd 23.0 mm; St. 26, NSMT E-7466, 1 specimen, dd 15.0 mm.
Depth range. 97–123 m.
Family Ophiolepididae Ljungman, 1867
Ophiopenia tetracantha H. L. Clark, 1911
(Fig. 9C–D)
Material examined. St. 01, NSMT E-7467, 1 specimen, dd 3.2 mm, NSMT E-7468, 2 specimens, dd 3.1–3.6 mm.

222

Toshihiko Fujita, Yoshiaki Ishida and Yoichi Kogure

Depth range. 124–126 m.
Remarks. A closely related species, Ophiopenia disacantha H. L. Clark, 1911, was found in the
Sea of Japan (Ishida et al., 2001). Ophiopenia disacantha can be distinguished from O. tetracantha by having only 2 arm spines instead of 4 or 5.
Acknowledgements
We are very grateful to Christopher Mah for reading and correcting the manuscript. We also
thank the staff of the Japan Sea National Fisheries Research Institute and the ofﬁcers and crewsof R/V Mizuho-maru for their cooperation in collecting materials. Alexander Martynov and Seiichi Irimura gave us helpful taxonomic suggestions. This paper is a contribution of the project“Research on Deep-sea Fauna of the Sea of Japan”. A part of this work is supported by a grant-inaid for scientiﬁc research (C, No. 25440226) from the Japan Society for the Promotion of Science to TF.
References
Clark, A. M., 1970. Notes on the family Amphiuridae (Ophiuroidea). Bulletin of the British Museum (Natural History),
Zoology, 19: 1–81.
Clark, H. L., 1911. North Paciﬁc ophiurans in the collection of the United States National Museum. Bulletin of the UnitedStates National Museum, 75: 1–301.
Clark, H. L., 1915. Catalogue of Recent Ophiurans based on the collections of the Museum of Comparative Zoology.
Memoirs of the Museum of Comparative Zoology, 25: 165–376, 20 pls.
Djakonov, A. M., 1954. Ophiuroids of the USSR Seas. 132 pp. Izadatelʼstvo Akademii Nauk SSSR, Moskva. (English
translation by Israel Program for Scientiﬁc Translation, 1967)
Duncan, P. M., 1879. On some Ophiuroidea from the Korean Seas. Journal of the Linnean Society of London, Zoology,
14(77): 445–482.
Fujita, T., Y. Ishida, T. Kato and S. Irimura, 2004. Ophiuroids (Echinodermata) collected from the Oki Islands in the Sea
of Japan. Bulletin of the National Science Museum, Series A (Zoology), 30(4): 191–218.
Fujita, T., U. Iwasaki and M. Okanishi, 2009. Ophiuroids (Echinodermata) of genus Ophiura collected from deep waters
off Paciﬁc coast of northern Japan. In: Fujita, T. (ed.), National Museum of Nature and Science Monographs,(39): 619–653.
Fujita, T. and H. Kohtsuka, 2003. Ophiuroids (Echinodermata) from Notojima Island and its adjacent waters in the Sea ofJapan. Report of the Noto Marine Center, (9): 25–38. (In Japanese with English Abstract.)
Irimura, S., 1979. Ophiuroidea of Sado Island, the Sea of Japan. Annual Report of the Sado Marine Biological Station,
Niigata University, (9): 1–6.
Irimura, S., 1991. Ophiuroidea. In: Echinoderms from Continental Shelf and Slope around Japan Vol. 2, pp. 111–152.
Japan Fisheries Resource Conservation Association, Tokyo.
Irimura, S., Y. Ishida and T. Kubodera, 1995. Catalogue of the Specimens of the Class Ophiuroidea (Echinodermata)Donated by Dr. Seiichi Irimura in the National Science Museum, Tokyo. 181 pp. National Science Museum,
Tokyo.
Ishida, Y., S. Ohtsuka, K. Takayasu, I. Kobayashi, Y.-G. Lee, K. Seto, H. Tanaka, K. Tamura, A. Go and K. Nakaguchi,
2001. Preliminary faunistic survey of ophiuroids in the westernmost part of the Sea of Japan. Journal of Facultyof Applied Biological Science, Hiroshima University, 40: 1–14.
Ishida, Y. and K. Tamura, 2004. Ophiuroides (Echinodermata) collected in the Sea around Nou Town, Niigata Prefecture,
central Japan. Bulletin of the Fossa Magna Museum, (3): 27–41.
Kogure, Y., 1999. Echinoderms from the lower-sublittoral zone on the north-western coasts of Sado Island, the Japan Sea.
Bulletin of the Japan Sea National Fisheries Research Institute, (49): 57–67. (In Japanese with English abstract.)
Kogure, Y., 2001. Depth/substrate relationships of echinoderms, off NW Hokkaido Island, Japan Sea. In: Echinoderms
2000, pp. 25–30. A. A. Balkema Publishers, Lisse.
Kogure, Y. and I. Hayashi, 1998. Bathymetric distribution pattern of echinoderms in the Sado Strait, the Japan Sea. Bulle-Ophiuroids of the Sea of Japan223

tin of the Japan Sea National Fisheries Research Institute, (48): 1–16.
Kogure, Y. and T. Nagasawa, 2004. Relationship between the distribution of Ophiura sarsii (Echinodermata, Ophiuroidea) and benthic environmental variables in the Sea of Japan. Biogeography, 6: 17–26.
Matsumoto, H., 1941. Report of the biological survey of Mutsu Bay. 36. Ophiuroidea of the Mutsu Bay and vicinities.
Science Reports of the Tôhoku Imperial University, Series 4, Biology, 16: 331–344.
Mortensen, T., 1933. Studies of Indo-Paciﬁc euryalids. Videnskabelige Meddelelser fra Dansk Naturhistorisk Forening i
Kjøbenhavn, 96: 1–75, 5 pls.
Okanishi, M., H. Tachikawa and T. Fujita, 2011. A record of a snake star Astrochele paciﬁca Mortensen, 1933 (Echinodermata: Ophiuroidea: Euryalida: Gorgonocephalidae) obtained from Katsuura, Chiba, Japan. Journal of the Natural History Museum and Institute, Chiba, Special Issue, (9): 97–102. (In Japanese with English abstract.)
Saito, H., K. Hasegawa, Y. Kogure, I. Yosho, Y. Ueda and T. Fujita, 2014. An outline of “Research on Deep-sea Fauna of
the Sea of Japan 2009–2013”. In: Fujita, T. (ed.), Deep-sea Fauna of the Sea of Japan. National Museum of Natureand Science Monographs, (44): 1–22.
Shin, H. C. and C. H. Koh, 1993. Distribution and abundance of ophiuroids on the continental shelf and slope of the East
Sea (southwestern Sea of Japan), Korea. Marine Biology, 115: 393–399.
Shin, S., 1992. A systematic study on the Ophiuroidea in Korea: II. Cheju Island. Korean Journal of Zoology, 35: 350–
361.
Shin, S., 1995. Echinodermata from Chindo Island, Korea. The Korean Journal of Systematic Zoology, 11: 115–124.
Shin, S. and B.-J. Rho, 1996. Illustrated Encyclopedia of Fauna & Flora of Korea. Vol. 36. Echinodermata. 780 pp. The
Ministry of Education, Seoul.
Smith, A. B., G. L. J. Paterson and B. Lafay, 1995. Ophiuroid phylogeny and higher taxonomy: Morphological, molecular and palaeontological perspectives. Zoological Journal of the Linnean Society, 114: 213–243.