Fauna Ryukyuana

ISSN 2187-6657
http://w3.u-ryukyu.ac.jp/naruse/lab/Fauna_Ryukyuana.html

First record of the snake mackerel Epinnula magistralis (Perciformes: Gempylidae)
from the Tokara Islands, Japan
1

Harutaka Hata1 & Hiroyuki Motomura2

The United Graduate School of Agricultural Sciences, Kagoshima University,
1–21–24 Korimoto, Kagoshima 890–0065, Japan
2
The Kagoshima University Museum, 1-21-30 Korimoto, Kagoshima 890-0065, Japan

Abstract. A single specimen of Epinnula magistralis(Perciformes: Gempylidae), collected off Taira
Island in the Tokara Islands, Kagoshima Prefecture,southern Japan, represents the first record of thespecies from the islands and sixth individual record
from Japanese waters. A detailed description of thespecimen is provided.
Introduction
Snake mackerels (family Gempylidae) are currently
represented in Japanese waters by 13 species(Nakabo & Doiuchi 2013; Nakayama et al. 2014). Of
these, the apparently rare Epinnula magistralis Poey,
1854 has been recorded only from Kumanonada(Mie Prefecture; Kamohara 1938; Matsubara & Iwai
1952), Tosa Bay, (Kochi Prefecture; Kamohara
1938), and Yoron Island (Kagoshima Prefecture;
Okamoto 2014).
During ichthyofaunal surveys in the Tokara
Islands, conducted as a part of the Kagoshima Fish
Diversity Project (e.g. Koeda & Motomura 2015a, b;
Hata et al. 2015a–d), a single specimen of E.
magistralis was obtained, having been an incidental
catch during commercial fishing operations off Taira
Island on 27 April 2015. The specimen, described indetail below, represents the sixth individual of thespecies recorded from Japanese waters.
Counts and proportional measurements followed
Nakamura et al. (1983) and Nakayama et al. (2014),
and are shown in Appendix 1. All measurements
were made with digital calipers to the nearest 0.1 mm.
Abbreviations: SL (standard length), KAUM
(Kagoshima University Museum, Kagoshima), andKUN (Kinki University, Nara).
Species accountEpinnula magistralis Poey, 1854
Standard Japanese name: Ao-sumiyaki(Fig. 1; Appendix 1)
Material examined. KAUM–I. 72269, 710.0 mm
SL, off Taira Island, Tokara Islands, Kagoshima
Prefecture, Japan, ca. 200 m depth, long line

(purchased at Kagoshima City Central Fish Market),
27 Apr. 2015, H. Hata.
Description. Body oblong, compressed laterally,
deepest at origin of pelvic fin. Abdomen rather
rounded, without mid-ventral keel. Caudal peduncle
cylindrical, without keels. Dorsal profile of body
convex from snout tip to origin of second dorsal-fin,thereafter decreasing rapidly to caudal-fin base.
Ventral profile of body convex from tip of lower jaw
to caudal-fin base. Head large, compressed laterally.
First dorsal-fin origin posterior to posteriormost
point of preopercle. End of first dorsal-fin baseslightly anterior to anal-fin origin. Second dorsal-fin
origin just above anal-fin origin. Posteriormost pointof second dorsal-fin base slightly behind posterior
end of anal-fin base. Uppermost point of pectoral-fin
insertion just below origin of third dorsal-fin spine.
Lowermost point of pectoral-fin insertion between
origins of fourth and fifth dorsal-fin spines.
Posteriormost point of pectoral fin reaching to avertical line through origin of ninth dorsal-fin spine.
Pelvic-fin origin posterior to posteriormost point ofpectoral-fin insertion. Posterior tip of pelvic finreaching to between vertical lines through origins of
ninth and tenth dorsal-fin spines when depressed.
Caudal fin forked. Snout pointed. Mouth terminal,
large, posterior tip of maxilla extending beyond levelof anterior margin of pupil. Eye and iris round.
Interorbital space flat. Nostrils closely paired, slitlike, anterior to orbit. Anus elliptical, located justbelow origin of 16th dorsal-fin spine. Body covered
with cycloid scales. All fins, jaws, snout, andpectoral-fin axillary region without scales. Posterioredges of preopercle and opercle smooth. Two ridges
on opercle. Two pairs of canine teeth on anterior partof upper jaw. Lateral teeth on upper jaw conical,
widely separated. Small uniserial conical teeth onpalatine. Vomer and tongue toothless. Single pair offangs near tip of lower jaw. Uniserial conical teeth
on lateral aspect of lower jaw. Jaws without dermal
processes. Gill rakers small, mostly embedded underskin. Pseudobranchial filaments present. Lateral line
inserted above upper end of opercle, closely
following dorsal profile to base of caudal fin; a lower
branch just before level of sixth dorsal-fin spine base
11

Fig. 1. (A) Left side and (B) right side of fresh specimen of Epinnula magistralis (KAUM–I. 72269, 710.0 mm SL,
Taira Island, Tokara Islands, Kagoshima Prefecture, Japan).
1.
Epinnula magistralis KAUM–I. 72269,
710.0 mm
200 m
(A);
(B)

descending and angling forward to near pelvic fin
origin, thereafter more or less following ventral
contour to caudal-fin base. Lower lateral-line on left
side of body interrupted between origins of pelvic fin
and anal fin (Fig. 1A).
Color when fresh (Fig. 1). Body silvery-gray,dark blue dorsally. Dorsal fin dark gray. Pectoral andpelvic fins bluish-black. Anal fin dark gray. Caudal
fin blackish-brown.
Color in alcohol. Body dark silver, fins dark gray.
Distribution. Epinnula magistralis has been
known from the Caribbean Sea (type locality:
Havana, Cuba); south of Lombok Island, Indonesia;
Taiwan; Japan; and the Hawaiian Islands (Poey1854; Grey 1953; Nakamura & Parin 1993; Mundy
2005; Ho & Yee 2012; Nakabo & Doiuchi 2013). In
Japan, the species has been recorded from the Tokara
Islands and Yoron Island, Kagoshima Prefecture;
Tosa Bay, Kochi Prefecture; Kii-Nagashima andKumanonada, Mie Prefecture (Kubo et al. 2012;
Nakabo & Doiuchi 2013; Okamoto 2014; this12

study).]
Remarks. The Tokara Islands specimen was
identified as E. magistralis on the basis of thefollowing combination of characters, which closely
matches the diagnostic features of E. magistralis
given by Nakamura & Parin (1993) and Nakabo &Doiuchi (2013): 16 spines on first dorsal fin; pelvic
fin with 1 spine and 5 soft rays; lateral line bifurcatedbelow fifth and sixth dorsal-fin spine bases, lower
branch running near ventral contour to caudal-finbase; no dermal processes on tips of jaws; abdomen
rather rounded, without mid-ventral keel; lateralsurface of caudal peduncle without keels; and vomer
toothless. In addition, meristic and morphometricdata for the present specimen were close to those for
a comparative specimen (750.0 mm SL) from Yoron
Island, Amami Islands, Japan (Appendix 1).
Both the present specimen (710.0 mm SL) andthat from the Amami Islands had pelvic fins shorter
than the pectoral fins, although Nakabo & Doiuchi(2013) noted a pelvic fin longer than the pectoral fin

Fauna Ryukyuana, 30: 11–15.

as diagnostic of E. magistralis. However, Okamoto(2014) noted shorter pelvic fins in larger examples ofthe species, the pectoral fins being shorter than thepelvic fins in individuals at least smaller than 335
mm SL.
The numbers of dorsal- and anal-fin soft rays of
the Pacific population of E. magistralis are higher
than those of the Atlantic population (18 and 16
respectively vs. 16 and 13 in the latter; Poey, 1854;
Grey, 1953; Nakamura & Parin 1993; Ho & Yee
2012; Okamoto 2014). The numbers of dorsal- andanal-fin soft rays of the Tokara specimens wellconsistent with those of the Pacific population given
in Ho & Yee (2012) and Nakabo & Doiuchi (2013).
Grey (1953) suggested that the Pacific and Atlantic
populations represent distinct species or subspecies.
Kamohara (1938) reported two specimens of E.
magistralis from Tosa Bay, Kochi Prefecture, andKumanonada, Mie Prefecture, proposing theJapanese name “Ao-sumiyaki” for the species. These
represented the first voucher specimen-based recordsof E. magistralis from Japanese waters.
Subsequently, Matsubara & Iwai (1952) reported an
individual (188 mm SL) of E. magistralis from off
Owase, Kumanonada, Mie Prefecture. Kubo et al.
(2012) reported the species from off Kii-Nagashima,
Mie Prefecture, based on a voucher specimen (KUNP 42742). Following Okamoto’s (2014) report of E.
magistralis from Yoron Island, Amami Islands,
Kagoshima Prefecture, based on a collected
specimen (KAUM–I. 51544), the present report isthe first record from the Tokara Islands and the sixth
individual record of the species from Japanesewaters.
Comparative material examined. Epinnulamagistralis: KAUM–I. 51544, 750.0 mm SL, off
Yoron Island, Amami Islands, Kagoshima Prefecture,
Japan, line fishing, 29 Oct. 2012, KAUM Fish Team.
Acknowledgements
We are especially grateful to T. Tanaka (Tanaka
Suisan Ltd.) for collecting the specimen. We also
thank Y. Haraguchi and other volunteers, andstudents of KAUM for their curatorial assistance. We
are also grateful to G. Hardy (Ngunguru, New
Zealand), who read the manuscript and provided
help with English. Thanks also go to two reviewers
who improved our manuscript. This study was
supported in part by the Sasakawa Scientific
Research Grant from the Japan Science Society (28745); Grants-in-Aid for Scientific Research (A:26241027, B: 24370041 and C: 23580259 and
26450265) from the Japan Society for the Promotionof Science, Tokyo, Japan (JSPS); Core-to-Core
Program, “Research and Education Network on
Southeast Asian Coastal Ecosystems”; the “Coastal
Area Capability Enhancement in Southeast Asia
Project” of the Research Institute for Humanity andNature, Kyoto, Japan; the “Biological Properties ofBiodiversity Hotspots in Japan” project of the
National Museum of Nature and Science, Tsukuba,
Japan; and “Establishment of Research and
Education Network on Biodiversity and Its
Conservation in the Satsunan Islands” project ofKagoshima University adopted by the Ministry of
Education, Culture, Sports, Science and Technology,
Japan.
References
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(3): 135–141.
Hata, H., Y. Haraguchi & H. Motomura, 2015a. First
record of Caranx lugubris (Perciformes:
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41: 69–72. [In Japanese]
Hata, H., Y. Haraguchi & H. Motomura, 2015b. First
record of Etelis radiosus (Perciformes:
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Annotationes Zoologicae Japonenses, 17: 45–50.

[Report] Hata & Motomura: First record of the snake mackerel from the Tokara Islands

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Koeda, K. & H. Motomura, 2015a. First record of
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トカラ列島平島から得られたクロタチカマス
科アオスミヤキ Epinnula magistralis
畑晴陵 ･本村浩之
1〒890‒0065 鹿児島県鹿児島市郡元 1‒21‒24
鹿児島大学大学院連合農学研究科
2〒890‒0065 鹿児島県鹿児島市郡元 1‒21‒30
鹿児島大学総合研究博物館

1.
Epinnula magistralis

Appendix 1. Counts and measurements of Epinnula magistralis
14

2

([
[.

)
1
[

.
,

6

: 2016: 2016: 2016

2
5
6

19
14
26

Fauna Ryukyuana, 30: 11–15.
1.

Epinnula magistralis
Taira Island,
Tokara Islands, Japan
KAUM–I. 72269

Yoron Island,
Amami Islands, Japan
KAUM–I. 51544

Standard length (SL)

710.0

750.0

Fork length

759.0

800.0

Dorsal-fin rays

XVI-I, 18

XVI-I, 18CountsAnal-fin rays

III, 16

III, 16

Pectoral-fin rays

15

15

Pelvic-fin rays

I, 5

I, 5

Head length

31.5

32.4

Orbit diameter

6.6

7.4

7.3

6.9

6.1

6.0

25.2

23.5

22.3

20.3

Measurements (% of SL)[%

Fleshy interorbital width(

Bony interorbital width
Body depth at pelvic-fin base[
Body depth at anal-fin origin[
Pectoral-fin length

(

)
)

20.0

18.4

Upper caudal-fin lobe length

24.8

18.5

Lower caudal-fin lobe length

16.6

brokenSnout length

11.7

11.2

Postorbital length

13.6

13.8

Upper-jaw length

15.3

15.8

Suborbital width

1.2

1.2

27.9

28.1

71.1

70.1

43.2

40.9

18.3

18.7

Pre-pectoral-fin length

31.0

33.5

Pre-pelvic-fin length

40.8

41.7

First pre-dorsal-fin length1

Second pre-dorsal-fin length
First dorsal-fin base length
Second dorsal-fin base length212Pelvic-fin length

10.5

10.0

Pre-anal-fin length

72.0

74.8

Pre-anus length

67.6

69.3

Anal-fin base length

16.0

15.5

Abdominal length

32.8

35.3

Tail length

29.9

29.6

Caudal-peduncle length

14.3

14.5

Caudal-peduncle depth

5.5

5.4

Caudal-peduncle width

2.0

1.9

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