Platax 14: 96-102, 2017

Records of rare scabbardfish (Perciformes: Trichiuridae)
from southern Taiwan
Keita Koeda1* and Hsuan-Ching Ho1,2
1National Museum of Marine Biology & Aquarium, 2 Houwan Rd., Checheng, Pingtung 944, Taiwan

2

Graduate Institute of Marine Biology, National Dong Hwa University, Checheng, Pingtung 944, Taiwan*Corresponding author. E-mail: hatampo@gmail.com.

Abstract
Specimens of two scabbardfish (Trichiuridae), Evoxymetopon poeyi
Günther, 1887 and Evoxymetopon taeniatus Gill, 1863, were recently
collected from waters of southern Taiwan. Neither species has been recorded
frequently in Taiwan, and their morphology is poorly documented. Therefore,
detailed descriptions of both species are provided herein based on theserecently collected Taiwanese specimens.
Key words: Evoxymetopon poeyi, Evoxymetopon taeniatus, ichthyology,
Trichiuridae, morphology, scabbardfish, taxonomy

Introduction

shape. Finally, their pelvic fins are
scale-like, and they have small, forked
caudal fins (Nakamura and Parin, 1993,2001). The species are known as
benthopelagic on continental shelf andslope. No special fishery for species ofthis genus, thus only a handful
information is known about the biology
and morphology.
Evoxymetopon poeyi Günther, 1887
and two specimens of E. taeniatus Gill,
1863 were recently collected from water
off southern Taiwan. Although theThe genus Evoxymetopon Bloch andSchneider, 1801 belongs to the family
Trichiuridae and comprises four validspecies (Nakamura and Parin, 1993, 2001;
Chakraborty et al., 2006). The upperprofiles of the heads of members of thegenus Evoxymetopon are convex (i.e.,
rising steeply from the tip of the snout tothe dorsal fin origin), forming a prominent
sagittal crest. Also, the posterior ends oftheir gill covers are broadly rounded, andtheir first anal-fin spines are scale-like in96

Platax 14: 96-102, 2017

former was previously found in Japan,
Taiwan, and Mauritius, and the latter has
been collected from Northwestern Asia
(Pacific Ocean) and the Western AtlanticOcean, only very few records exist, andtheir morphology is still poorly described.
Therefore, these two Taiwanese species
are described in detail herein.

respectively.
Themorphologicaldescriptions are based on the specimens
collected from Taiwan. The specimens ofthe genus Evoxymetopon examined in thisstudy are deposited at the National
Museum of Marine Biology & Aquarium(NMMB-P).

Results
Materials and Methods

Family Trichiuridae
Evoxymetopon Gill, 1863
Evoxymetopon poeyi Günther, 1887
卜氏窄顱帶魚Figures. 1-2; Table 1

The three specimens were obtained
from southern Taiwan (see specimensexamined). Collected specimens are deadwhen obtained. Counts and measurements
follow Sakiyama et al. (2011).
Measurements were made to the nearest
0.1 mm with digital calipers (Mitutoyocorporation) when possible, but somecharacters were measured to the nearest
1 mm with traditional calipers or
measuring tape. Standard, total, and fork
lengths are abbreviated as SL, TL, and FL,

Evoxymetopon poeyi Günther, 1887: 39,
pl. 43 (type locality: Java, Indonesia);
Nakamura and Parin 1993:88;
Chakraborty et al. 2006: 137;
Nakabo and Doiuchi, 2013:1644;
Chiang et al. 2014:292, unnumberedfig.; Hata et al. 2016:321.

Fig. 1. Fresh specimen of Evoxymetopon poeyi from waters off Kenting, Taiwan.
NMMB-P26093: 1840 mm SL, 1885 mm TL, and 1860 mm FL.

97

Platax 14: 96-102, 2017

Fig. 2. Head of Evoxymetopon poeyi (upper: NMMB-P26093, 1840 mm SL) andE. taeniatus (lower: NMMB-P27279, 1483 mm SL) collected fromsouthern Taiwan.

Fig. 3. Fresh specimen of Evoxymetopon taeniatus from waters off Dong-gang,Taiwan. NMMB-P27295: 1315 mm SL, 1353 mm TL, and 1335 mm FL.

98

Platax 14: 96-102, 2017

Specimen examined. NMMB-P26093,
1840 mm SL (1885 mm TL and 1860 mmFL), male (semen leaked out), collectedoff Kenting (21°54ʹN, 120°46ʹE),Pingtung, South China Sea, Taiwan, 25May 2017, collected by Michael Lin.
Description of Taiwanese specimen.
Counts and measurements are shown in
Table 1. Body extremely elongate, deep,strongly compressed, ribbon-like, andtapering to a point posteriorly with a small,forked caudal fin. Body depth 12.7 times
in SL. Head strongly pointed; profile
convex steeply rising from tip of snout todorsal-fin origin, forming a prominent
sagittal crest. Head length 8 times in SL.
Interorbital space keeled. A single,slit-like nostril. Mouth large, with thegape extending to beneath anterior half ofeye. Jaws not protractile; lower jaw
extends anteriorly to upper jaw. Threepairs of strong, fang-like teeth in anterior
part of upper jaw. Anus located anterior tocenter of body.
Dorsal fin low and long, beginning
shortly behind posterior margin of eye.
First dorsal-fin spine elongated, about 1.3
times of head length; anterior spinous
portion slightly shorter than posterior soft
portion (two portions). Anal fin low,
beginning shortly behind anus; firstanal-fin ray scale-like, with the other raysembedded. Pectoral fins short and low inposition. Pelvic fins scale-like, without
rays. Singular lateral line, mostly runningalong center of body. Scales absent. Color

generally silver, though faintly dusky athead and caudal-peduncle when fresh.
First elongated dorsal-fin spine blackish.
Distribution. Evoxymetopon poeyi is
only known from scattered localities,including Japan, Taiwan, Indonesia, andthe Cook Islands in the Pacific Ocean andMauritius and Réunion Island in theIndian Ocean (Froese and Pauly, 2017,online version). This species waspreviously found off Eastern Taiwan(Chiang et al., 2014), and its range
evidently extends into southern Taiwan
based on the present study.
Remarks. The characteristics of thepresent Taiwanese specimen is wellconsistent with the diagnosis of E. poeyi
given by Nakamura and Parin (1993) andNakabo and Doiuchi (2013): firstdorsal-fin spine elongated, slit-likenostrils, and body depth 12.6 times in SL.
Although E. poeyi is similar in appearance
to Evoxymetopon macrophthalmum
Chakraborty, Yoshino and Iwatsuki, 2006,
in which the only known holotype is from
Okinawa-jima island, the former is clearly
distinguishable from the latter in having 1)
an eye diameter 5.5-5.8 times its headlength (vs. 4.5 in the latter), 2) a convex
upper head profile rising steeply from thetip of the snout (vs. moderately rising),and 3) a keeled interorbital zone (vs. notkeeled) (Chakraborty et al., 2006; Nakaboand Doiuchi, 2013).
Although Shen and Wu (2011)
reported E. poeyi in Taiwan, they only99

Platax 14: 96-102, 2017presented one monochrome drawing intheir manuscript. Chiang et al. (2014)
documented E. poeyi from off the eastern
coast of Taiwan with a photograph of alanded individual (FRIP 21653, 177 cmFL). Therefore, the present specimen
represents the first record of this species
from southern Taiwan, and the first recordof this species in the South China Sea.

pectoral-fin base 11.8-11.9 times in SL.
Head moderately pointed; profile convex
and rising steeply from tip of snout todorsal-fin origin forming a prominent
sagittal crest. Head length 7.8-8.1 times inSL. Interorbital zone keeled. A single,crescent nostril. Mouth large, with thegape extending to beneath anterior half ofeye; jaws not protractile, with lower jaw
extending anteriorly to upper jaw. Threepairs of strong, fang-like teeth in anterior
part of upper jaw. Anus located anterior tocenter of body.
Dorsal fin low and long, beginningabove center of eye. First dorsal-fin spine
not elongated and anterior spinous portion
longer than posterior soft portion (twoportions continuous). Anal fin low,
beginning shortly behind anus; firstanal-fin ray scale-like, other rays
embedded. Pectoral fins short and low inposition. Pelvic fins scale-like and without
rays. Singular lateral line running mostly
along center of body. Scales absent. Color
generally silver and faintly dusky at
caudal-peduncle when fresh. Anterior
portion of dorsal-fin membrane blackish.
Distribution. Evoxymetopon taeniatus is
known from the central Atlantic Ocean
and northwestern Pacific Ocean off Japan,
Taiwan, Korea and the Philippines(Froese and Pauly, 2017, online version).
This species was previously found off
Eastern Taiwan (Chiang et al., 2014), andits range evidently extends into southern
Taiwan based on the present study.

Evoxymetopon taeniatus Gill, 1863條狀窄顱帶魚Figures 2-3; Table 1
Evoxymetopon taeniatus Gill, 1863: 228(type locality: Cuba); Nakamura andParin, 1993:89; Chen 2003:204;
Chakraborty et al. 2006:137;
Sakiyama et al. 2011:105, figs. 5-6;
Nakabo and Doiuchi 2013:1644;
Chiang et al. 2014:292, unnumberedfig.
Specimens examined (n=2).
NMMB-P27279: 1483 mm SL (1520 mm
TL, 1499 mm FL). NMMB-P27295: 1315mm SL (1353 mm TL, 1335 mm FL).
Both collected off Dong-gang (22°39ʹN,120°24ʹE), Pingtung, South China Sea,Taiwan, 20 June 2017, purchased byH.-C. Ho at Dong-gang fish market.
Description of Taiwanese specimens.
Counts and measurements are shown in
Table 1. Body extremely elongate, deep,strongly compressed, ribbon-like, andtapering to a point posteriorly with a small,forked caudal fin. Body depth at100

Platax 14: 96-102, 2017

Chen, C.-H. 2003. Fishes of Penghu. Fisheries
Research Institute, Council of Agriculture,Keelung. 379 pp. (in Chinese)
Chiang ,W.-C., P.-L. Lin, W.-Y. Chen & D.-C.
Liu. 2014. Marine fishes in eastern
Taiwan. Fisheries Research Institute,Keelung. 337 pp. (in Chinese)
Froese, R. & D. Pauly (eds.). 2017. FishBase.
World Wide Web electronic publication.
www.fishbase.org, version (06/2017)
Hata, H., M. Takayama & H. Motomura. 2016.
First records of Evoxymetopon poyei(Perciformes:Trichiuridae)
from
Kagoshima Prefecture, southern Japan.
Nature of Kagoshima, 42: 321-325. (inJapanese)
Nakabo, T. & R. Doiuchi. 2013. Trichiuridae.
Pp. 1644-1647, 2221-2224. In: Nakabo, T.
(ed): Fishes of Japan with pictorial keys
to the species, third edition. TokaiUniversity Press, Hadano, Japan. (InJapanese)
Nakamura, I. & N.V. Parin. 1993. FAO
species catalogue. Snake mackerels andcutlassfishes of the world (familiesGempylidae and Trichiuridae). FAO
Fishes Synopsys, 125 (15): i-viii + 1-136.
Nakamura, I. & N.V. Parin. 2001. Trichiuridae.
Pp. 3709-3720. In: Carpenter, K.E. &V.H. Niem (eds): FAO Species
Identification Guide for Fishery Purposes.
The Living Marine Resources of theWestern Central Pacific, Vol. 6. Bony
Fishes Part 4 (Labridae to Latimeriidae),
Estuarine Crocodiles, Sea Turtles, Sea
Snakes and Marine Mammals. Rome,Italy, FAO.
Sakiyama, T., H. Senou, A. Mishiku, Y. Kanou& T. Itoh T. 2011. First records of twospecies of the Myliobatid rays, Atrobatus
flagellum and Mobula diabolus from
Sagami Bay with a certain record of raretrichiurid fish, Evoxymetopon taeniatus.
Bulletin of the Kanagawa PrefecturalMuseum of Natural History, 32: 101-108.
(In Japanese with English abstract)Shen, S.-C. & Wu, K.-Y. (2011) Fishes ofTaiwan. National Museum of Marine
Biology & Aquarium, Checheng, 896 pp.
(in Chinese)

Remarks. The characteristics of the twopresent specimens are well consistent
with the diagnosis of E. taeniatus ofNakamura and Parin (1993; 2001)
and Nakabo and Doiuchi (2013):
first dorsal-fin spine not elongated,crescent nostrils, and body depth
11.7-11.9 times in SL. E. taeniatus isrelatively similar morphologically toE. poeyi but is easily distinguishedby the aforementioned characteristics.
Although Shen and Wu (2011)
documented E. taeniatus in Taiwan,
and even provided a photograph ofthe specimen, the locality was notmentioned. Also, Chiang et al. (2014)
reported a single individual of E.
taeniatus off the eastern coast ofTaiwan (FRIP21653, 174 cm FL).
Therefore, the present specimen
represents the first reliable record ofthis species from southern Taiwan.

Acknowledgements
We are especially grateful to R.-R.
Chen, J.-F. Huang, J.-T. Lin, and A.
Koeda (NMMB-P) for curatorialassistance. The present study wassupported in part by a JSPS Overseas
Research Fellowships (29-304) to K.K.

References
Chakrabortyet, A., T. Yoshino & Y. Iwatsuki Y.
2006. A new species of scabbardfish,
Evoxymetopon
macrophthalmus(Scombroidei: Trichiuridae), fromOkinawa, Japan. Ichthyological Research,
53(2): 137-142.

101

Platax 14: 96-102, 2017

Table 1. Counts and measurements of Evoxymetopon poeyi and E. taeniatus
collected from southern Taiwan.

Standard length (SL; mm)
Total length (mm)Fork length (mm)Counts
Dorsal fin elements
Pectoral fin rays
Pelvic fin rays
External anal fin rays
Caudal fin rays
Measurements (% of SL)
Pre-anus length
Head length
Snout length
Postorbital length
Preopercle length
Upper-jaw length
Body depth at pectoral-fin base
Body width at pectoral-fin base
Body depth at anus
Body width at anusFirst dorsal-fin spine lengthPre-dorsal-fin length
Dorsal-fin base length
Orbit diameter
Suborbital widthInterorbital width
Depth above lateral line at anus
Depth below lateral line at anus
Pre-pectoral-fin length
Pectoral-fin base length
Pectoral fin length
Pre-pelvic-fin length
Pelvic-fin lengthPre-anal-fin length
Anal-fin base length
Caudal-peduncle depth
Caudal-peduncle length
Tail length

E. poeyi
Off KentingNMMB-P26093
1840
1885
1860

E. taeniatus
Off Dong-gang
NMMB-P27279 NMMB-P27295
1483
1315
1520
1353
1499
1335

90
121
178+781121
208+782
12
1
18
8+7

49.5
12.5
4.9
6.1
1.7
4.5
7.9
2.0
7.0
1.6
16.8
9.5
92.4
2.3
0.9
1.7
3.8
3.3
13.3
1.0
6.5
16.7
1.2
50.3
48.5
0.5
1.4
48.0

50.0
12.4
4.5
6.0
1.9
4.9
8.5
2.2
7.4
1.7
2.6
7.5
94.9
1.9
1.1
1.9
4.1
3.6
13.4
1.4
damaged
17.1
0.8
52.1
47.30.5
1.8
50.1

48.1
12.8
4.8
6.0
2.1
4.5
8.4
2.1
7.9
1.7
2.6
7.9
93.6
2.0
1.3
1.9
4.5
3.7
13.8
1.4
6.6
17.7
0.9
49.2
51.1
0.5
1.9
52.0

102