B i ogeogra phy 13.
69–71．Sep. 20, 2011

First record of the cusk-eel, Neobythites australiensis
Nielsen (Ophidiiformes: Ophidiidae), from the Northern Hemisphere
Makoto Okamoto1*, Jørgen G. Nielsen2 and Hiroyuki Motomura3
1

Seikai National Fisheries Research Institute, 1551-8 Taira-machi, Nagasaki 851-2213, Japan2
Natural History Museum of Denmark, University of Copenhagen,
Universitetsparken 15, DK-2100, Copenhagen, Denmark3
The Kagoshima University Museum, 1-21-30 Korimoto, Kagoshima 890-0065, JapanAbstract. A single specimen (167 mm standard length) of the cusk-eel (Ophidiidae), Neobythites australiensis Nielsen, 2002, was collected from west of Okinawa Island, Japan. This species was previously known only
from northwestern Australia. The Japanese specimen represents the first record of the species from the Northern Hemisphere; it is given a new Japanese name, Niten-itachiuo.
Key words: Ophidiidae, Neobythites australiensis, cusk-eel, distribution, Japan.

Introduction
The genus Neobythites Goode and Bean, 1885
is known from all subtropical and tropical oceans
except for the East Atlantic and is the most speciose
genus within the family Ophidiidae (Nielsen et al.
1999; 2009). In his revision of the Indo-Pacific species of the genus, Nielsen (2002) described 15 newspecies. One of them, Neobythites australiensis wasdescribed on the basis of seven specimens collectedfrom off northwestern Australia, at depths of 42–350
m (Nielsen 2002).
There have been no reports of the species being
collected since the original description. In 1998, asingle specimen of genus Neobythites was collectedfrom west of Okinawa Island, Japan. Recently, thespecimen was identified as N. australiensis by thesecond author. The current paper documents the firstrecord of the species from the Northern Hemisphere*Corresponding author : okamako@affrc.go.jp

based on the Japanese specimen.
Count and proportional measurement methods
follow Nielsen (2002). Vertebral counts and osteological features were examined from soft X-ray negatives. The term ocellus on the vertical fin is used
for a dark spot surrounded by a white ring (Uibleinand Nielsen 2005; fig. 1). Standard and head lengths
are abbreviated as SL and HL respectively. The Japanese specimen of N. australiensis is deposited at theKagoshima University Museum, Japan (KAUM),
the data for which is as follows: KAUM–I. 37071,
167 mm SL, female, west of Okinawa Island, Japan,East China Sea, ca. 100 m depth, 16 May 1998. The
following two specimens of Neobythites unimaculatus Smith and Radcliffe, 1913 deposited at theLaboratory of Marine Biology, Faculty of Science,
Kochi University, Japan (BSKU) were examined forcomparative purposes: BSKU 37006, 204 mm SL,Mimase Fish Market, Kochi, Japan, 250 m depth, 14April 1982; BSKU 37542, 203 mm SL, Mimase FishMarket, Kochi, Japan, depth unknown, 19 October
1982.

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Neobythites australiensis from Japan

Results and Discussion
The Japanese specimen (Fig. 1) is identified as
Neobythites australiensis on the basis of the following combination of characters: hind margin of preopercle with two spines, lower spine longer; dorsal
fin with one ocellus positioned behind a line throughanus; smaller black botch on anterior dorsal fin;dorsal-fin rays 92; anal-fin rays 75; pectoral-fin rays26; long rakers on anterior gill arch 10; pelvic-fin
length 19.0% SL; longest gill filaments on anteriorarch 7.0% HL; pseudobranchial filaments 6; vomerine tooth patch subtriangular; precaudal vertebrae
13; and total vertebrae 54. These characters of thepresent specimen agree with all diagnostic charactersof N. australiensis given by Nielsen (2002), except

for 6 pseudobranchial filaments (vs. 8–11 in typespecimens). This character varies considerably forsome species in the genus (e.g., 5–10 in N. longipes,
see Nielsen 2002: table 13). Also, there are twominor morphometric differences between the Japanese specimen and the type specimens: head length(23.0% SL in Japanese specimen vs. 23.5–24.5%
SL in type specimens); and diameter of eye window(5.0% SL vs. 4.2–4.7% SL). We consider these minor differences as intraspecific variation.
The principal meristic and morphometric (expressed as percentage of SL except for the lengthof the longest filaments on anterior gill arch, HL)characters of the Japanese specimen are as follows:
dorsal-fin rays 92; anal-fin rays 75; caudal-fin rays
8; pectoral-fin rays 26; pelvic-fin rays 2; long rakers

Fig. 1. Neobythites australiensis, KAUM–I. 37071, 167 mm SL, west of Okinawa Island, Japan.

Fig. 2. Distributional records of Neobythites australiensis. Specimen examined in this study (star)and Nielsen (2002) (triangles).

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Makoto Okamoto, Jørgen G. Nielsen and Hiroyuki Motomura

on anterior gill arch 10; vertebrae 13 + 41; pseudobranchial filaments 6; origin of dorsal fin above vertebra no. 5; origin of anal fin below dorsal-fin ray no.
22; origin of anal fin below vertebra no. 15; HL 23.0;
depth at origin of anal fin 18.5; upper jaw length
12.0; diameter of eye window 5.0; postorbital length14.0; preanal length 44.5; predorsal length 25.0;
base of pelvic fin to anal-fin origin 28.0; pectoral-fin
length 12.5; pelvic-fin length 19.0; and longest filaments on anterior gill arch 7.0% HL.
In the review of the Indo-Pacific species of Neobythites (Nielsen 2002), three congeners were recorded from Japanese waters: Neobythites sivicola(Jordan and Snyder, 1901); Neobythites stigmosus
Machida, 1984; and N. unimaculatus. Neobythites
australiensis can be easily distinguished from thesespecies by the presence of a black blotch and anocellus on the dorsal fin (vs. blotches absent in N.
sivicola; 3–7 ocelli or blotches in N. stigmosus; andonly one ocellus in N. unimaculatus, see Nielsen2002).
Neobythites australiensis has a mottled patternon the dorsal part of head and body; however, someolder type specimens are less mottled apparently due
to bleaching (Nielsen 2002). The mottled pattern inthe present specimen was also indistinct, possibly
due to fading during preservation (Fig. 1).
Because this species has been reported only fromthe northwestern Australia (Nielsen 2002; Hoese etal. 2006), our specimen represents the first recordof Neobythites australiensis from the NorthernHemisphere (Fig. 2). A new standard Japanese name,
Niten-itachiuo (meaning two spotted cuskeel),is proposed here for N. australiensis, reflecting thepresence of a black botch and an ocellus on the dorsal fin.

Acknowledgements
We sincerely thank D. Cohen (California Academy of Sciences) and M. McGrouther (AustralianMuseum) for their valuable comments on the initialmanuscript. We are grateful to D. Hoese (Australian Museum) for providing literature, S. Morrison(Western Australia Museum) for providing information on the holotype of N. australiensis, and H. Endo(BSKU) for a specimen loan.

References
Hoese, D. F., Paxton, J. R., Gates, J. E. & Bray, D.
J., 2006. Ophidiidae. In Hoese, D. F., Bray, D.
J., Paxton, J. R. & Allen, G. R. (Eds), Zoological
Catalogue of Australia. Vol. 35, part 2: 556–566.
ABRS & CSIRO Publishing, Collingwood.
Nielsen, J. G., 2002. Revision of the Indo-Pacificspecies of Neobythites (Teleostei, Ophidiidae),with 15 new species. Galathea Rep., 19: 1–104.
Nielsen, J. G., Cohen, D. M., Markle, D. F. & Robins, C. R., 1999. Ophidiiform fishes of the world(Order Ophidiiformes). An annotated and illustrated catalogue of pearlfishes, cusk-eels, brotulas
and other ophidiiform fishes known to date. FAOSpecies Catalogue, 18. FAO Fish. Synopsis No.
125(18). xi, 178 pp. FAO, Rome.
Nielsen, J. G., Uiblein, F. & Mincarone, M. M.,
2009. Ocellus-bearing Neobythites species (Teleostei: Ophidiidae) from the West Atlantic with description of a new species. Zootaxa, 2228: 57–68.
Uiblein, F. & Nielsen, J. G., 2005. Ocellus variationand possible functions in the genus Neobythites(Teleostei, Ophidiidae). Ichthyol. Res., 52: 364–372.
(Received April 28, 2011; Accepted June 23, 2011)− 71 −