Bull. Natl. Mus. Nat. Sci., Ser. A, Suppl. 6, pp. 1–16, March 30, 2012

Three New Species of Ophichthid Eels
(Anguilliformes: Ophichthidae) from Japan
John E. McCosker1, Sachiko Ide2 and Hiromitsu Endo3
1

California Academy of Sciences, San Francisco, California 94118, USA
E-mail: jmccosker@calacademy.org
2
2–9–38 Kume-cho, Sakaide, Kagawa 762–0003, Japan
E-mail: kabomizo@js4.so-net.ne.jp
3
Laboratory of Marine Biology, Faculty of Science, Kochi University,
2–5–1 Akebono-cho Kochi 78–8520, Japan
E-mail: endoh@kochi-u.ac.jp

Abstract Three new species of ¿shery research and ¿sh market specimens of Japanese ophichthid eels are described and illustrated. Scolecenchelys fuscapenis sp. nov. is described on the basisof 21 specimens from 112–269 m depth from Tosa Bay and Niigata; it is unique in its vertebral
number (157–162), dentition (jaw teeth bi- and triserial), dorsal-¿n origin (1 head length beforeanus), and coloration (a prominent black spot on its posterior tail region). It is proposed that themelanistic tail pigment serves to strengthen the tail region of tail-burrowing eels. Ophichthus
machidai sp. nov., subgenus Coecilophis, is described from 23 specimens from approximately
30–150 m depth from Tosa Bay, Uchinour Bay, and the Kii-suido channel. It is unique in its vertebral number (150–161), single (typically) labial barbel, 2 (typically) minute preopercular pores,
and its small uniserial dentition. Ophichthus obtusus sp. nov., subgenus Coecilophis, is describedfrom 21 specimens from approximately 30–150 m depth from Tosa Bay and the Kii-suido channel.
It is unique in its blunt snout condition, its vertebral number (148–153), two labial barbels, 3 preopercular pores, and its small uniserial dentition. The vertebral numbers of Japanese Ophichthus
are tabulated and a key to the species is provided.
Key words: Ophichthidae, new snake eels, Ophichthus, Scolecenchelys, Japan.

The snake eels of the tropical and subtropicaleel family Ophichthidae are the most species richof anguilliform ¿shes, comprising as many as
260 species worldwide (McCosker et al., 1989,
and unpublished data). Ophichthids occupy avariety of marine habitats, ranging from midwater to reefs to sand and mud substrates, usually at
depths less than 100 m, although some species of
the genus Ophichthus are found as deep as1300 m. The Japanese Archipelago possess alarge and diverse ophichthid fauna (Asano, 1984;
Hatooka, 2002), with at least 40 valid described
species and several more are likely to be discovered. To this assemblage we add three new species collected from the Kii-suido channel,
Niigata, Uchinoura Bay, and from Tosa Bay, off
the south coast of Kochi Prefecture in Shikoku

Island, an area with an active trawl ¿shery, a history of ichthyological and academic researchers,
and a rich ichthyofauna (Kamohara, 1964; Shinohara et al., 2001; Ide et al., 2003; Ide, 2004).
Materials and Methods
Measurements are straight-line, made eitherwith a 300 mm ruler with 0.5 mm gradations (fortotal length, standard length, trunk length, andtail length) and recorded to the nearest 0.5 mm,or with dial calipers (all other measurements)
and recorded to the nearest 0.1 mm. Body length
comprises head and trunk lengths. Head length ismeasured from the snout tip to the posterodorsal
margin of the gill opening; trunk length is takenfrom the posterior end of the head to mid-anus;

2

J. E. McCosker, S. Ide and H. Endomaximum body depth does not include themedian ¿ns. Head-pore terminology follows thatof McCosker et al. (1989: 257) such that the
supraorbital pores are expressed as the ethmoidal
pore＋pores in its supraorbital canal, i.e., 1＋3,
and the infraorbital pores are expressed as pores
along the upper jaw＋those in vertical part of thecanal behind the eye (the “postorbital pores”),
i.e., 4＋2, in that frequently the last poreincluded along the upper jaw is part of the postorbital series. Vertebral counts (which include thehypural) were taken from radiographs. The meanvertebral formula (MVF) is expressed as theaverage of predorsal, preanal, and total vertebrae(Böhlke, 1982). Institutional abbreviations follow the Standard Symbolic Codes for Institutional Research Collections in Herpetology andIchthyology (Leviton et al. 1985). The seniorauthor has examined all of the holotypes of the
ophichthid eels mentioned in this study except
those of Ophichthus habereri, which wasdestroyed, and O. ophis. Information concerning
those specimens is available in Eschmeyer(2012).
Genus Scolecenchelys Ogilby, 1897
Diagnosis. Ophichthid eels, Subfamily Myrophinae, tribe Myrophini. Body elongate, laterallycompressed posteriorly. Pectoral ¿n absent.
Anterior nostril tubular; posterior nostril opens
into mouth, covered by an exterior Àap; 2 pores
between nostrils. Jaw teeth conical, in 1–3 rows;
intermaxillary teeth not in a broad patch.
Remarks. The genus Scolecenchelys was until
recently considered to be a subgenus of Muraenichthys (Castle and McCosker, 1999). They separated the species of Scolecenchelys from thoseof Muraenichthys based on the number of labial
pores (two vs. one) between the anterior and posterior nostrils, their dentition (conical vs. blunt),
and the posterior nostril location (beneath upper
lip vs. outside of upper lip). There are at least
18–20 species within Scolecenchelys and 7–8
species within Muraenichthys. It is very likelythat additional species will be discovered.

Scolecenchelys fuscapenis sp. nov.
[New English name: Black Tailed Worm Eel]
[New Japanese name: Tsumaguro-mimizu-anago](Figs. 1–3, Table 1)
Scolecenchelys sp.: Ide, 2004: 12.

Holotype. NSMT-P 106570 (formerly BSKU
96046, photo), 337 mm TL, female, Tosa Bay,
33°14.70ƍN, 133°38.42ƍE–33°13.01ƍE, 133°36.55ƍE,
223–269 m, R/V Kotaka-maru, otter trawl, St.
T5–1, coll. by K. Nashida and N. Nakayama, 26
Aug. 2008.
Paratypes. 20 specimens (19 specimens, Tosa
Bay; 1specimen, Sea of Japan). Tosa Bay, Japan(R/V Kotaka-maru, otter trawl): AMS I. 45671001 (formerly BSKU 99523), 302 mm, 33°14.92ƍN,
133°38.02ƍE–33°13.59ƍE, 133°36.00ƍE, 213–202 m,
coll. by K. Nashida and H. Sakaji, 6 July
2006; BSKU 64911, 365 mm, 33°12.6ƍ N,
133°35.7ƍE–33°11.1ƍE, 133°33.7ƍE, 252–258 m,
St. 6–2, coll. by K. Nashida and H. Sakaji, 16
June 2003; BSKU 76475, 236 mm, 33°14.81ƍN,
133°38.06ƍE–33°13.23ƍN, 133°35.67ƍE, 214–212 m,
St. T5-1, by K. Nashida and H. Sakaji, 17 Nov.
2005; BSKU 77928, 2 (255–338 mm), 33°15.07ƍN,
133°38.36ƍ E–33°16.30ƍN, 133°40.21ƍE, 207–
201 m, St. T5-1, by K. Nashida and H. Sakaji, 17
Apr. 2006; BSKU 84462, 334 mm, BSKU 84463,
296 mm, ca. 250 m, 9 Mar. 1998 (the precise data
are unknown); BSKU 85268, 306 mm, BSKU
85269, 325 mm, 33°13.2ƍN, 133°36.9ƍE–33°13.0ƍN,
133°36.2ƍE, 232–246 m, 8 June 1998; BSKU
98015, 260 mm, BSKU 98016, 302＋mm (taildamaged), 33°14.67ƍN, 133°37.83ƍE–33°15.72ƍE,
133°39.31ƍE, 205–207 m, St. T5-1, coll. by K.
Nashida and N. Nakayama, 24 Feb. 2009;
BSKU 99516, 285 mm, 33°14.82ƍN, 133°38.32ƍE–
33°13.53ƍN, 133°35.30ƍE, 224–182 m, St. T5-1,
coll. by K. Nashida and S. Yamamoto, 14 July
2009; BSKU 99524, 304 mm, collected withAMS I. 45671-001; BSKU 99747, 318 mm,
BSKU 99748, 283 mm, BSKU 99749, 330 mm,
collected with BSKU 99516; BSKU 102889,
367 mm, 33°14.88ƍN, 133°38.12ƍE–33°13.26ƍN,
133°35.79ƍE, 212–215 m, St. T5-1, coll. by K.

Three New Species of Ophichthid Eels

3

Fig. 1. Holotype of Scolecenchelys fuscapenis sp. nov. in fresh condition, NSMT-P 106570, 337 mm TL. Photographedby N. Nakayama.

Fig. 2. Head of holotype of Scolecenchelys fuscapenis sp. nov., NSMT-P 106570, 337 mm TL. Illustration by Juliana
Olsson.

Nashida, 8 Mar. 2010; CAS 231945 (formerly
BSKU 102890), 317 mm, collected with BSKU
102889; NSMT-P 106571 (formerly BSKU
99746), 357 mm, collected with BSKU 99747;
USNM 404480 (formerly BSKU 77928, 1 of 3),
302 mm TL, collected with BSKU 77928. Sea ofJapan: USNM 151440, 208 mm, Niigata, Sea ofJapan (38°12ƍN, 138°52ƍE), 112 m, Albatross St.
4817, 18 July 1906.

Diagnosis. An elongate species of Scolecenchelys with the following characteristics: tail65–67% of TL; dorsal ¿n arising 1 HL before
anus; 3 preopercular pores; teeth numerous, slender, small and conical, maxillary teeth triserial,mandibular teeth biserial, vomerine teeth uniserial posteriorly; total vertebrae 157–161; andMVF 34/50/162 (n＝9).
Counts and measurements (in mm) of the holo-

4J. E. McCosker, S. Ide and H. Endo
Table 1. Counts and proportions (in thousandths)of the holotype (NSMT-P 106570) and 9 paratypes of Scolecenchelys fuscapenis sp. nov.
(AMS I.45671-001, BSKU 64911, BSKU
98015, BSKU 99516, BSKU 99524, BSKU
99748, BSKU 102889, CAS 231945, NSMT-P
106571 and USNM 404480). TL＝Total length.
HL＝head length.

Fig. 3. Semi-diagrammatic illustration of dentition ofholotype of Scolecenchelys fuscapenis sp. nov.,
NSMT-P 106570, 337 mm TL. Illustration by
Claire Schneider.

type. Total length 341; standard length 337; head
27.4; trunk 89.6; tail 220; predorsal distance 87;
body depth at gill openings 8.7; body width at

Mean

Range

TL (mm)HL/TL
Head and trunk/TL
Tail/TL
Depth at gill opening/TL
Dorsal-¿n origin/TL
Upper jaw/HL
Snout/HL
Eye/HLInterorbital/HL
Gill opening/HL
Predorsal vertebrae
Preanal vertebrae

—
83
341
659
22
250
311
218
105
103
52
23.3
47.6

260–367
79–89
330–351649–670
19–26
231–270
290–347
206–244
79–116
77–128
41–65
32–35
46–50

Total vertebrae

160

157–162

gill openings 7.4; body depth at anus 7.9; bodywidth at anus 7.3; snout 6.7; tip of snout to tip oflower jaw 1.5; tip of snout to rictus of jaw 9.5;
eye diameter 2.6; interorbital distance 3.1; gillopening length 1.5. Vertebral formula 33/48/160.
Left lateral line pores minute, the majority
uncountable, 8 in branchial region, 48 preanal.
Description. (Based on the holotype and 9paratypes, see Table 1.) Body elongate (Fig. 1),
depth at gill openings 41–65 in TL, tapering andlaterally compressed posteriorly. Head and trunk
short, 2.8–3.0 and head 11.2–12.6 in TL. Snout
moderately acute; a short median ventral groove
extends from a line across center of anterior nostrils forward to anterior edge of anterior nostrils.
Lower jaw included, its tip reaching anterioredge of anterior nostrils. Anterior nostrils tubular, their length about one half eye diameter. Posterior nostril entirely inside upper lip, before
anterior margin of eye, opening inward, appearing externally as a Àap. Eye diameter about equal
to interorbital distance. Interorbital region Àat.
Rictus of jaw beneath posterior margin of eye.
Median ¿ns low. Dorsal ¿n arises 1 head length
before level of anus origin. Paired ¿ns absent.
Median ¿ns conÀuent with caudal.

Three New Species of Ophichthid Eels

Head pores minute (Fig. 2). Single temporaland interorbital pores. Supraorbital pores 1＋3,
infraorbital pores 4＋2; two pores between anterior and posterior nostrils. Six pores along mandible, 3 overlying preopercle. Lateral-line poresdif¿cult to discern posteriorly; 9 pores before
right gill opening; approximately 130 pores
along right side, approximately 60 before theanus. Last lateral-line pore occurs about a headlength before tail tip.
Teeth (Fig. 3) numerous, slender, small andconical. Triserial on maxillary and biersial on
mandible. A patch of 7 intermaxillary teeth, followed by 17–22 (17 in holotype) irregular teethon vomer; 30–33 (30) irregular pairs of maxillaryteeth Àanked posteriorly by a third row of 40–45(44) teeth, and approximately 35–40 (40) irregular pairs of mandibular teeth, largest at symphysis.
Body coloration of a freshly captured specimen is shown in Fig. 1. In ethanol, it is yellowish-brown, becoming darker on upper half due tosmall, closely spaced punctations, becoming uniform yellow-brown in posterior half of tailregion. Median ¿ns transparent except near caudal tip. Tail tip prominently blackened in posteriormost region for a length approximately equal
to jaw length, extending onto median and caudal¿ns. Anterior nostril, upper lip, and inside ofmouth pale. Dorsal surface of peritoneum freckled with ¿ne dark punctations. Eye dark blue.
Size. The largest known specimen is 367 mm
TL, a ripe male.
Etymology. From the Latin fuscus (dark) andpenis (tail), in reference to its coloration.
Distribution. Known only from Tosa Bay andNiigita, Japan, collected from muddy and sandy
bottoms between 112–269 m depth.
Remarks. The holotype of the new species is a
gravid female with densely packed ova (〜0.6 mm
in diameter).
The depth of capture of the new species is
extraordinary within Scolecenchelys. Except for
Scolecenchelys castlei McCosker, 2006, a New
Zealand and Australian species from 425–820 m
depth, Scolecenchelys puhioilo (McCosker, 1979),

5

a Hawaiian species known only from the holotype which was trapped in 275 m, and Scolecenchelys
profundorum (McCosker and Parin, 1995),
trawled at 310 m on the Nazca Ridge, most species of Scolecenchelys live in tidepools down to afew meters depth.
The new species appears to be most closely
related to species of Scolecenchelys whose dorsal¿n originates in advance of the anus, including:S. breviceps (Günther, 1876), S. castlei, S. cookei(Fowler, 1928), S. godeffroyi (Regan, 1909),
S. macroptera (Bleeker, 1857), S. puhioilo, andS. xorae (Smith, 1962). Possessing 157–162
vertebrae, the new species has signi¿cantly morevertebrae than S. cookei (131–136), S. godeffroyi(〜143), S. macroptera (127–135), and S. xorae(139–144), and fewer than S. breviceps (161–
167) and S. castlei (180–186). The only known
specimen of S. puhioilo has 160 vertebrae. The
tail length of S. fuscapenis is longer than that ofany of the above-mentioned congeners (65–67%
vs. 55–63% of TL). All of those congeners
have conical biserial maxillary dentition except
S. puhioilo which has uniserial dentition.
All known species of Scolecenchelys are similar in having a nearly uniform tan coloration(although slightly darker dorsally) when in preservative. The two deepwater species, S. fuscapenis
and S. puhioilo, differ in having black pigmentation along the posteriormost region of the tail.
That of S. puhioilo is limited to the posterior portion of the anal ¿n approximately one headlength before the tail tip. The black portion of thetail tip of S. fuscapenis is shorter in length but
extends across the median and caudal ¿ns. (Thetail region and ¿ns of their deepwater congeners
S. castlei and S. profundorum are not blackened.)
Several ophichthids, particularly some but not all
deepwater species of Ophichthus (see McCosker,
2010), as well as the deepwater congrid Congriscus
megastomus, also possess a darkened portion of
the anal ¿n and/or tail tip. No one has hypothesized a function for such a darkly pigmented ¿n.
We discount the possibility that it would serve a
signal function in such burrowing eels. We suspect, rather, that it might bene¿t those eels that

6

J. E. McCosker, S. Ide and H. Endodig into the substrate with their tails. It has beenshown that eumelanin is a potent antioxidant andcould serve to protect an organism that is in close
contact with substrates that harbor toxic metals
and/or peroxide ions (McGraw, 2005); the limited amount of blackened tissue on this eelʼs tailmakes such a function less likely. It is wellknown that melanistic keratin in bird feathers
and beaks is more effective than non-melanistic
keratin in resisting abrasive wear (Bonser, 1995;
Bonser and Witter, 1993). We propose that themelanistic pigment serves a similar purpose by
structurally strengthening the tail of these eels
which bury into the substrate tail-¿rst. We areunaware of differences in the substrate composition of preferred habitats of different species of
deepwater Scolecenchelys or Ophichthus but suspect that it may relate to the bene¿t of a hardened
tail ¿n.
Genus Ophichthus Ahl, 1789
Diagnosis. Ophichthid eels, Subfamily
Ophichthinae, tribe Ophichthini. Body moderately to very elongate, cylindrical, and laterallycompressed posteriorly. Head and trunk shorter
than tail. Dorsal ¿n arises above or behind gill
openings. Pectoral ¿n developed, ranging from
paddle-shaped to elongate. Snout and jaws moderately elongate. Lips without numerous barbels
or fringes. Anterior nostrils tubular; posterior
nostrils open into mouth or along lower edge oflip. Eye moderately to well-developed. Teeth
conical and numerous, never caniniform, fromuniserial to multiserial on jaws and vomer. Coloration variable, often marked, but generally uniform and darker dorsally.
Remarks. The genus Ophichthus (sensu lato)is the most speciose of ophichthids, with approximately 65–70 (several undescribed) tropical andsubtropical species worldwide. The generic synonyms of Ophichthus are listed in McCosker etal. (1989: 379). Several subgenera are recognizable within Ophichthus, though a worldwide
revision has yet to be accomplished. The two
new species of Ophichthus that we describe
here belong to the subgenus Coecilophis. The
subgenus Coecilophis Kaup 1856 [type species
Ophisurus apicalis Anonymous (Bennett, 1830)]
was recognized as a subgenus of Ophichthus by
McCosker (1977). Nearly all deepwater IndoPaci¿c species of Ophichthus belong to Coecilophis (McCosker, 2010). Only one eastern Paci¿cspecies (O. arneutes, from the Gal㎝agos
Islands) and only one western Atlantic species(O. brevirostris, from North Carolina) is within
the subgenus Coecilophis.
It is useful to comment upon McCoskerʼs(2010) observations of the behavior of an eastern
Paci¿c species of the subgenus Coecilophis suchthat it allows an inference of the behavior of our
new species which were collected by deepwater
trawl. He wrote (pp. 2–3) “I ¿rst encountered,observed, and collected O. arneutes while diving
aboard the manned submersible Johnson SeaLink at 485 m off the Galápagos Islands (McCosker and Rosenblatt, 1998). It was observed on
three occasions at 434–557 m. Individuals wereobserved feeding somewhat like heterocongrine
garden eels, their heads and trunks extending
from the sand slopes within which they were buried, picking at passing plankton in the current.
They withdrew when frightened by the submersible, leaving only their snout tips exposed. Species of the subgenus Coecilophis are generally
pale and weakly pigmented, and some have darkened snouts, chins, and anterior nostrils, whereas
others have anterior nostril tubes that are muchpaler than the surrounding snout. Such coloration
may be correlated with camouÀage when they
are withdrawn into the substrate, and with signaling behavior between those individuals whichhave contrasting coloration of their snouts andanterior nostril tubes.”

Key to the Japanese Species of Ophichthus
1a. Body coloration markedly spotted or with distinct dark saddles; dorsal-¿n origin (DFO) above

Three New Species of Ophichthid Eels

7gill openings, in advance of pectoral-¿n tips; pectoral ¿ns rounded, not elongate . . . . . . . . . . . . 2
1b. Body coloration uniform, darker dorsally, without distinct spotting or distinct dark saddles; DFO
above or behind pectoral ¿ns; pectoral ¿ns rounded or elongate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2a. Body overlain with 18–27 prominent dark saddles, a conspicuous wide saddle above the gill
opening, and numerous golden to brown (in life) marblings on snout and face; vertebrae 156–164
Ophichthus bonaparti (Kaup, 1856)
2b. Body overlain with numerous dark or ocellated spots, those spots not appearing as saddles . . . . . 3
3a. Head and body overlain with numerous ocellated spots, those on body in 3 regular alternatingrows, the spots separated by pale interspaces; vertebrae 141–148. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophichthus polyophthalmus Bleeker, 1864
3b. Head and body overlain with numerous dark spots, those on body in 2 irregular rows, the spots
about equal in size to their interspaces; vertebrae 151–155. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophichthus erabo (Jordan and Snyder, 1901)
4a. DFO behind gill opening by more than 3 pectoral-¿n lengths; vertebrae 160–163 . . . Ophichthus
megalops Asano, 1987
4b. DFO in advance of, above, or slightly behind (less than one pectoral-¿n length) gill opening . . . 5
5a. Body moderately elongate, its depth 45–48 times in total length; vomerine teeth and jaw teeth
biserial; 2 preopercular pores (POP); vertebrae 169–173 . . . . Ophichthus stenopterus Cope, 1871
5b. Body less elongate, its depth less than 40 times in total length; teeth may be uniserial or biserial;
2 or 3 POP (those pores may be minute and dif¿cult to observe) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
6a. Dorsal surface of trunk and tail overlain with brown irregular blotches, ventral surface distinctly
pale; dorsal surface of head and gill basket brownish-black; DFO above mid-pectoral ¿n; pectoral ¿ns elongate, not pointed; teeth uniserial; vertebrae 151–153. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophichthus lithinus (Jordan and Richardson, 1908)1
6b. Dorsal surface of head and trunk tan to brown, without irregular blotches; head lacks a dark
nuchal band; DFO location variable, above or slightly behind pectoral ¿ns; pectoral-¿n shapevariable; teeth uniserial or biserial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
7a. DFO slightly behind end of pectoral ¿ns; pectoral ¿ns spatulate; 3 POP; jaw teeth uniserial; vertebrae 134–139 . . . . . . . . . . . . . . . . . . . . . . Ophichthus urolophus (Temminck and Schlegel, 1846)2
7b. DFO in advance of or slightly behind end of pectoral ¿ns; pectoral ¿ns rounded or elongate; 2 or
3 POP; jaw teeth uniserial or biserial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88a. Body coloration brownish-black, paler ventrally; median ¿ns black; rear margin of orbit above or
slightly behind rictus; 2 cauliÀower-shaped labial barbels; vertebrae 148–159. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophichthus obtusus sp. nov.
8b. Body coloration yellow to brown dorsally, paler ventrally; median ¿ns pale or with a dark margin; rear margin of orbit in advance of rictus; 1 or 2 smooth-surfaced labial barbels . . . . . . . . . . . 9
9a. Dorsal ¿n with a dark margin; pectoral ¿ns brownish-black; teeth uniserial; vertebrae 171–182. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophichthus altipennis (Kaup, 1856)3
9b. Dorsal ¿n margin not notably darkened; pectoral ¿ns pale; teeth uniserial or biserial . . . . . . . . 1010a. Pectoral ¿n spatulate, shorter than jaw; 3 POP; teeth uniserial; vertebrae 126–132. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ophichthus asakusae Jordan and Snyder, 1901
10b. Pectoral ¿n elongate, equal to or longer than jaw; 2 POP; vomerine teeth biserial centrally, max1

McCosker et al. (2006: 272) recognized O. evermanni Jordan and Richardson, 1909 as a junior synonym of O. lithinus(Jordan and Richardson, 1908).
2
Ophichthus urolophus (Temminck and Schlegel, 1846) includes Ophichthus tsuchidae Jordan and Snyder, 1901.

8

J. E. McCosker, S. Ide and H. Endoillary teeth uniserial; vertebrae 150–161 . . . . . . . . . . . . . . . . . . . . . . . Ophichthus machidai sp. nov.

Ophichthus machidai sp. nov.
[New English name: Machidaʼs snake eel][New Japanese name: Machida-umihebi](Figs. 4–6, Tables 2, 3)
Ophichthus sp. 1: Ide (2004: 38).

Holotype. NSMT-P 106572 (formerly BSKU
68428), 580 mm TL, female, west of Tosa Bay,
Saga ¿sh market (33°04.48ƍN, 133°06.80ƍE),
Kuroshio-cho, Kochi Prefecture, Japan, bottom
trawl, coll. by Y. Matsuoka and K. Inoue, 4 Dec.
2003.
Paratypes. 22 specimens. 15 from west of
Tosa Bay, off Kuroshio-cho, Kochi Prefecture,
Japan. From Kamikawaguchi ¿sh market(33°02.27ƍN, 133°03.55ƍE): AMS I. 45672-001(formerly BSKU 65174), 500 mm, 18 Mar. 2002;
BSKU 58930, 406 mm, coll. by T. Yamakawa
and M. Nakae, 10 Aug. 2001; BSKU 60738,
569 mm, coll. by Y. Machida et al., 30 Oct. 2002;
BSKU 83553, 474 mm, 31 July 1997; CAS
231946 (formerly BSKU 58158), 549 mm, agravid female with densely packed ova (〜0.5 mm
in diameter), collected with BSKU 58930. From
Irino ¿sh market (33°00.73ƍN, 133°00.60ƍE):
BSKU 83171, 587 mm, 27 May 1997. From Saga¿sh market: BSKU 58465, 585 mm, coll. by Y.
Nogawa et al., 20 Nov. 2002; BSKU 62674,
474 mm, coll. by H. Endo et al., 3 Oct. 2002;
BSKU 65076, 449 mm, 22 June 2002; BSKU
66275, 521 mm, USNM 404481 (previously
BSKU 66276), 529 mm, coll. by M. Nakae et al.,31 Aug. 2003; BSKU 72119, 497 mm, coll. by Y.
Machida et al., 14 May 2004; NSMT-P 106573(formerly BSKU 64237), 576 mm, coll. by Y.
Machida et al., 21 Apr. 2003; USNM 404481(previously BSKU 66276), 529 mm, collected3with BSKU 65076. From Tosa Bay: BSKU
87093, 570 mm, data unknown. 5 specimensfrom the Kii-suido channel (34°00ƍN, 134°50ƍE):
FAK 19243, 655 mm, 3 Aug. 1983, 70–80 m;
FAK 19630, 582 mm, 6 Aug. 1986; FAK 19631,
515 mm, 6 Aug. 1986; FAK 19633, 468 mm, 6Aug. 1986; FAK 19638, 672 mm, 28 May 1983.
2 specimens from off Tsushiro (31°17ƍN,
31°05ƍE), Uchinour Bay, Kouyama, Kimotsuki,
Kagoshima Prefecture, Japan, set net at 40 m,
coll. by M. Yamada, 20 Feb. 2007, KAUM
03944 (519 mm) and KAUM 06869 (513 mm).
Diagnosis. A moderately elongate species of
Ophichthus with the following characters: tail53–61% TL and head 8.5–10% TL; dorsal-¿norigin above or slightly behind pectoral ¿n; pectoral ¿ns elongate, longer than jaw; posterior
nostril opening within mouth; single labial barbel; head pores minute, dif¿cult to observe, SO 1
＋4, IO 4＋2, POM 2＋5; teeth small andnumerous, biserial centrally and uniserial anteriorly and posteriorly on vomer, uniserial on maxillary and mandible; coloration pale ventrally,brown dorsally, ¿ns pale; mean vertebral formula
13/56/154, total vertebrae 150–161 (n＝10).
Counts and measurements (in mm) of the holotype. Total length 580; head 51.6; trunk ; tail 341;
predorsal distance 77.1; pectoral-¿n length 19.3;
pectoral-¿n base 5.7; body depth at gill openings
18.5; body width at gill openings 16.7; body
depth at anus 18.5; body width at anus 17.6;
snout 9.4; tip of snout to tip of lower jaw 2.8; tipof snout to rictus 14.2; eye diameter 5.9; interorbital distance 7.7; gill-opening height 7.6; isthmus width 〜11. Vertebral formula 16/58/158.
Left lateral line pores minute, the majority
uncountable, 9 in branchial region, 57 preanal.
Description. Body (Fig. 4) moderately elongate, laterally compressed in posterior tail region,

We follow McCosker and Randall (2002) in recognizing O. melanochir as a junior synonym of O. altipennis. We follow
Hatooka (2002: 1457) and recognize Pisodonophis zophistius Jordan and Snyder, 1901 and Ophichthys intermedius Regan,
1905 as synonyms of O. altipennis.

Three New Species of Ophichthid Eels

Fig. 4.

Fig. 5.

9

Holotype of Ophichthus machidai sp. nov., NSMT-P 106572, 580 mm TL. Illustration by Juliana Olsson.

Head of holotype of Ophichthus machidai sp. nov., NSMT-P 106572, 580 mm TL. Illustration by Juliana Olsson.

depth at gill openings 27–40 in TL. Branchialbasket slightly wider and deeper than body. Headand trunk short, 2.1–2.6 in TL; head 10–12 in
TL, 2.8–3.9 in trunk. Snout conical, acute whenviewed from above. Snout bisected on underside
by a groove from posterior margin of anterior
nostril to anterior margin of posterior nostril.
Lower jaw included, upper and lower lips almost
meeting when mouth is closed. Underside ofsnout with numerous minute Àeshy bristles in
ethmoidal region. Mouth moderately elongate,
rictus beneath rear margin of eye. Eye 2.3–2.4 inupper jaw and 7.3–11.3 in head, its center wellbehind middle of upper jaw. Tube of anterior
nostril short, anterolaterally inclined, hardly
capable of being deÀected forward. A small barbel beneath 2nd infraorbital pore, about 1/3 thedistance between anterior and posterior nostrils.
A second small pore usually present beneath thecenter of the orbit. Posterior nostril opens into
mouth, not visible along margin of lip. Dorsal-¿norigin above or slightly behind pectoral ¿n; dorsal ¿n low in anterior trunk region, elevated inposterior trunk region. Anal ¿n elevated. Pectoral¿ns elongate, rounded posteroventrally, longer
than jaw in length. Pectoral ¿n (Fig. 5) arises
above gill opening and extends to mid-opening.
Head pores (Fig. 5) minute, inconspicuous.
Single median interorbital and temporal pores.
Supraorbital pores 1＋4, infraorbital pores 4＋2,
mandibular pores 5, preopercular pores 2, rarely
3. Lateral-line pores present but too small to enumerate, 9 before gill opening.
Teeth (Fig. 6) conical, small, very close set
and erect. Intermaxillary with an irregularly biserial patch of 3–5 teeth, followed by a gap, followed by a uniserial row of 6–7 (6 in holotype)
teeth, then 5–6 (6) pairs of vomerine teeth which10

J. E. McCosker, S. Ide and H. Endo

become a uniserial row of 〜5–6 teeth. Maxillaryteeth linear and uniserial, 29–30 (30) teeth oneach side, becoming smaller posteriorly. Mandibular teeth strictly uniserial, 36–40 (37) teeth oneach side, becoming smaller posteriorly.
Color in ethanol pale ventrally, brown above
lateral midline; cheeks, throat and ¿ns pale;
median ¿n bases darkened; a ¿ne brown speckling overlays pale region of body and tail; lower
lip, anterior chin region and anterior nostrils
darkened; palate overlain with ¿ne brown speckling; peritoneum pale.
Size. The largest known specimen is 672 mm
TL (FAK 19631), a gravid female captured in theKii-suido channel.
Etymology. Named in honor of Yoshihiko
Machida, who guided Sachiko Ide through herthesis at BSKU.
Distribution. Known only from the type
series, from Kuroshio-cho, Kochi Prefecture, theKii-suido channel separating Honshu and Shikoku islands, and from Uchinour Bay,
Kagoshima Prefecture, Japan. Specimens were
captured at approximately 30–150 m depth.
Remarks. The holotype of O. machidai is afemale with eggs 〜0.3–0.5 mm in diameter. Allof the FAK specimens captured in the Kii-suidochannel during late May and early August were
gravid females with well developed ova.
The range of total vertebrae of ten specimensof this species is expressed in Table 3. We haveexcluded two paratypes (BSKU 65174 and FAK
19631) which have 13/52/146 and 12/48/145 vertebrae, signi¿cantly less than the range of theother paratypes (150–161). It is not uncommon
for individuals of a large sample of an eel species
to have abnormally reduced vertebral numbers
resulting from developmental Àaws or damaged
and healed tails.
The new species is unique within Ophichthus
and would not be mistaken for any of its Japanese congeners. Minute Àeshy bristles are welldeveloped on the ethmoidal region of the underside of the snout (Fig. 6). Such structures arepresent on the lips and ethmoidal region of otherspecies of Ophichthus, however they are wellFig. 6. Semi-diagrammatic illustration of dentition ofholotype of Ophichthus machidai sp. nov., NSMTP 106572, 580 mm TL. Illustration by Claire
Schneider.

developed in O. machidai. They probably serve a
sensory function but have not been comprehensively analyzed within the genus. It shares several characters with some deepwater (living at or
below 200 m) Indo-Paci¿c species of Ophichthus

Three New Species of Ophichthid Eels
Table 2. Vertebral counts of valid Japanese speciesof Ophichthus. Sources: 1) this study; 2) McCosker and Randall, 2002; 3) Sumida andMachida, 2000; 4) McCosker, 2002; 5) Asano,
1987; 6) Asano, 1984; 7) Randall, 2007; 8)
Böhlke, 1982; 9) McCosker, 2010.
As described

Holotype

MVF

Range Source

altipennis
9/52/178 9/56/176 171–182 1,2
asakusae
11/54/128 11/54/130 126–132 1,3
bonaparti
9/89/164 9/89/164 163–164 1,4erabo
6/78/155 8/27/153 151–155
1lithinus
13/72/153 12/70/152 151–153
1machidai
16/58/158 13/56/154 150–161
1megalops
29/60/160 30/61/162 160–163 1,5obtusus12/57/151 11/55/151 148–153
1
polyophthalmus 8/74/145 8/74/145 141–149 1,6,7
stenopterus
17/63/169* 18/59/170 169–173 1,8
19/66/173*
urolophus
16/54–136 16/54/136 134–139 1,9* syntypes(McCosker, 2010), such as its pale coloration,
numerous conical and uniserial teeth, its moderately elongate body depth, the location of its dorsal-¿n origin, its pectoral-¿n condition (elongate,
but not attenuate), and having two preopercularpores. The preopercular pore numbers (either 2,
3, or 4) of species of Ophichthus is a useful indicator of phylogeny (McCosker, 1977). The presence of a small labial barbel between the anterior
and posterior nostrils is probably a signi¿cantcharacter among species of Ophichthus; it has
not yet been comprehensively assessed.
Ophichthus machidai is similar to Ophichthus
microstictus McCosker, 2010, known from 362–
450 m depth off Fiji and Tonga, and possibly a
specimen from 200 m off New Caledonia. It issimilar to O. machidai in its vertebral condition(O. microstictus has MVF 13/56/152, total vertebrae 151–156 vs. O. machidai MVF 13/56/154,
total vertebrae 150–161) its preopercular pores(2–3 vs. 2), and its head (10.8–11.3% vs. 8.5–
10%) and tail proportions (57–59% vs. 53–61%).
It differs from O. machidai in lacking a smalllabial barbel between the anterior and posterior
nostrils, in its pectoral-¿n length (less than the
jaw length vs. greater than the jaw length) and inits dentition (less numerous, slightly larger, andirregularly biserial on the maxillary). The new

11

Table 3. Counts and proportions (in thousandths)of the holotype (NSMT-P 106572) and 9 paratypes of Ophichthus machidai sp. nov. (BSKU
58158, BSKU 58465, BSKU 58930, BSKU
60738, BSKU 65076, BSKU 72119, BSKU
87093, CAS 231946 , KAUM O6869 and
USNM 404481). TL＝total length. HL＝head
length.
Mean

Range

TL (mm)HL/TL
Head and trunk/TL
Tail/TL
Depth at gill opening/TL
Dorsal-¿n origin/TL
Pectoral-¿n length/HL
Upper jaw/HL
Snout/HL
Eye/HLInterorbital/HL
Gill opening/HL
Isthmus/HL
Predorsal vertebrae
Preanal vertebrae

—
89
414
586
30
124
363
290
223
114
136
115
239
13.1
56.1

406–579
85–100
388–468
532–612
25–37
110–131
320–404
205–332
186–258
93–136116–150
81–138
212–287
11–16
52–59

Total vertebrae

154.3

150–161

species is also similar to the eastern Paci¿c species Ophichthus apachus McCosker and Rosenblatt, 1989 and Ophichthus longipenis McCosker
and Rosenblatt, 1989, both of which have thesingle barbel, two preopercular pores, and dorsal¿n origins and pectoral-¿n shapes similar to thatof O. machidai. They differ in having more vertebrae (176–186) and biserial upper jaw dentition, and are much more elongate (body depth
1.4–2.5% of TL). Other New World species withsimilar dorsal-¿n origins, pectoral-¿n conditions,and the presence of a minute labial barbel
between the nostrils are: Ophichthus cylindroideus (Ranzani, 1839), Ophichthus mecopterus
McCosker and Rosenblatt, 1989 (which has two
additional labial barbels), Ophichthus ophis (Linnaeus, 1758), Ophichthus rugifer Jordan and
Bollman, 1890, and Ophichthus triserialis(Kaup, 1856). All however typically have three,rather than two, preopercular pores and possess
quite different body colorations.

12

J. E. McCosker, S. Ide and H. Endo

Ophichthus obtusus sp. nov.
[New English name: Pug-nosed snake eel][New Japanese name: Shishi-gashira-umihebi](Figs. 7–9; Tables 2, 4)
Ophichthus sp. 2.: Ide (2004: 40).

Holotype. NSMT-P 106574 (previously BSKU
71725), 684 mm TL, a gravid female, west of
Tosa Bay, Irino ¿sh market, Kuroshio-cho, Kochi
Prefecture, Japan, 4 Mar. 2004.
Paratypes. 20 specimens. 18 from west of
Tosa Bay, off Kuroshio-cho, Saga ¿sh market:
AMS I.45673-001 (formerly BSKU 83168),
630 mm, female, 1 May 1997; BSKU 56056,
560 mm, 10 Aug. 2000; BSKU 56850, 614 mm,

Fig. 7.

Fig. 8.

coll. by T. Yamakawa and M. Nakae, 26 Aug.
2001; BSKU 60521, 697 mm, female, coll. by K.
Nishida, 16 Oct. 2002; BSKU 60737, 575 mm,coll. by Y. Machida et al., 30 Oct. 2002; BSKU
64546, 731 mm, female, BSKU 64547, 513 mm,coll. by Y. Machida et al., 29 Nov. 2002; BSKU
65078, 566 mm, female, coll. by Y. Takata et al.,22 June 2003; BSKU 68429, 573 mm, female,
BSKU 68430, 633 mm, coll. by Y. Matsuoka andK. Inoue, 4 Dec. 2003; BSKU 72117, 531 mm,
female, coll. by Y. Machida et al., 14 May 2004;
BSKU 77288, 630 mm, coll. by Y. Machida etal., 11 Dec. 2004; BSKU 90890, 632 mm, coll.
by Y. Machida et al., 15 Apr. 2007; BSKU
101341, 540 mm, male, BSKU 101342, 543 mm,
female, coll. by Y. Machida et al., 15 Nov. 2009;

Holotype of Ophichthus obtusus sp. nov., NSMT-P 106574, 684 mm TL. Illustration by Juliana Olsson.

Head of holotype of Ophichthus obtusus sp. nov., NSMT-P 106574, 684 mm TL. Illustration by Juliana Olsson.

Three New Species of Ophichthid Eels

CAS 231947 (formerly BSKU 68432), 664 mm,
NSMT-P 106575 (previously BSKU 68431),
690 mm, female, coll. by Y. Matsuoka and K.
Inoue, 4 Dec. 2003. USNM 404482 (previously
BSKU 64544), 570 mm, collected with BSKU
64545. 2 specimens from the Kii-suido channel(34°00ƍN, 134°50ƍE): FAK 15097, 553 mm,
female, 5 Nov. 1978; FAK 19242, 695 mm,
female, 3 Aug. 1983, 70–80 m.
Diagnosis. A moderately elongate species of
Ophichthus with the following characters: tail1.7–1.8 and head 10.9–11.9 in TL; body depth atgill openings 29–37 times in TL; dorsal-¿n origin
above pectoral-¿n tips; pectoral ¿ns short,slightly longer than jaw; posterior nostril withinmouth; upper jaw short, rear margin of orbit
above or slightly behind rictus; snout short,blunt; 2 labial cauliÀower-shaped barbels; head
pores minute, SO 1＋4, IO 4＋2, POM 3＋5;
teeth small and numerous, uniserial on vomer
and jaws; coloration yellow ventrally, brownishblack dorsally, median ¿ns black; mean vertebral
formula 11/55/151, total vertebrae 148–153 (n＝10).
Counts and measurements (in mm) of the holotype. Total length 684; head 61.5; trunk 232.5;
tail 390; predorsal distance 79.1; pectoral-¿nlength 17.3; pectoral-¿n base 6.6; body depth atgill openings 〜26; body width at gill openings〜21; body depth at anus 〜30; body width atanus 〜24; snout 10.6; tip of snout to tip of lower
jaw 4.0; tip of snout to rictus 14.2; eye diameter
5.8; interorbital distance 12.6; gill-opening
height 〜7; isthmus width 〜8.5. Vertebral formula 12/57/151. Left lateral line pores minute,the majority uncountable, 8 in branchial region,
56 preanal.
Description. Body (Fig. 7) moderately elongate, tail laterally compressed, depth at gill openings 29–37 in TL. Branchial basket wider anddeeper than body. Head and trunk short, 2.2–2.4
in TL; head 10.9–11.9 in TL, 3.7–4.2 in trunk.
Snout short and conical, acute when viewed fromabove. Snout bisected on underside from midanterior nostril to slightly in advance of anterior
nostril base by a groove. Lower jaw included,

13

upper and lower lips meet when mouth is closed.
Underside of snout with numerous minute Àeshy
bristles in ethmoidal region. Mouth short, rictus
ahead of rear margin of eye. Eye 2.1–3.2 inupper jaw and 10–16 in head, its center far
behind middle of upper jaw. Tube of anterior
nostril extends slightly below margin of lower
lip. Small cauliÀower-shaped barbels immediately behind base of anterior nostril and beneath
2nd infraorbital pore, followed by a second smallcauliÀower-shaped barbel beneath eye and 3rd
infraorbital pore (Fig. 8). Posterior nostril opens
into mouth, not visible along margin of lip, andcovered by a Àap. Dorsal-¿n origin slightly inadvance of pectoral-¿n tips. Dorsal ¿n low, in agroove. Anal ¿n slightly more elevated, in agroove similar to that of dorsal. Pectoral ¿ns
short, not elongate, central rays longest, slightly
longer than jaw. Pectoral-¿n base arises justabove and extends below middle of gill opening.
Head pores (Fig. 8) small, inconspicuous
except for supraorbital series. Single medianinterorbital and temporal pores. Supraorbital
pores 1＋4, infraorbital pores 4＋2, mandibularpores 5, preopercular pores 3.
Teeth (Fig. 9) conical, not enlarged. Intermaxillary with 5 teeth in an irregularly biserial row,followed by a gap, then a patch of 7 teeth, followed by a row of 35–40 (40) uniserial teeth onvomer, becoming smaller posteriorly. Maxillaryteeth uniserial, 18–21 (21) teeth in a row. Mandibular teeth small, about 5 pairs at symphysis
followed by 22–25 (24) teeth in a uniserial row.
Color in ethanol pale yellow ventrally, brownish-black on mid-Àank and dorsal surface. Snouttip, tip of mandible, anterior nostrils, and tailpale. A dark halo encircles anal opening. Pectoral¿ns brown. Median ¿ns black. Inside of mouth
dusky with ¿ne brown punctations. Peritoneumpale.
Size. The largest known specimen is 697 mm
TL, a female (BSKU 60521).
Etymology. From the Latin obtusus (blunt) inreference to its snout condition.
Distribution. Known only from the type series,
from Kuroshio-cho, Kochi Prefecture, and the

14

J. E. McCosker, S. Ide and H. Endo

Fig. 9. Semi-diagrammatic illustration of dentition ofholotype of Ophichthus obtusus sp. nov., NSMT-P
106574, 684 mm TL. Illustration by Claire Schneider.

Kii-suido channel separating Honshu and Shikoku islands, Japan. Specimens were captured at
approximately 30–150 m depth.
Remarks. The holotype is a gravid female witheggs 〜0.4–0.7 mm in diameter. The FAK specimens captured in the Kii-suido channel, likethose of O. machidai, were gravid females. The
large paratype (FAK 19242), collected in August,has very well-developed ova.
The new species could not be mistaken forother Japanese congeners using the characters inour diagnostic key. The condition of its smalllabial barbels, cauliÀower-shaped rather thansmooth, appears to differ from that of other barbel-bearing ophichthids.
This new species is similar in appearance andproportions to Ophichthus habereri (Franz,
1910), described from a 90 cm specimen from
Yokohama. The specimen was destroyed during
WWII and has received little notice since its
description (Eschmeyer, 2012). Franzʼs illustration and description indicate a robust eel with ananterior dorsal-¿n origin and uniserial teeth. Itseye position is slightly more anterior and thelength of its jaw is considerably longer than thatof O. obtusus, and we thereby consider it to be adifferent species.
Ophichthus obtusus is similar to the shallow
water (shoreline to 22 m depth), widely distributed Indo-Paci¿c (Kenya to Madagascar, Thailand, Philippines and Korea) species O. apicalis(Bennett, 1830). They have the same labial barbel number (both have a second barbel beneaththe orbit), similar head proportions and dentition,
have a dark dorsal ¿n, and similar vertebral numbers (O. obtusus has a MVF 12/55/151, total vertebrae 148–153 vs. O. apicalis with a MVF
12/52/144, total vertebrae 143–145). Ophichthus
obtusus differs in its preopercular pore condition(O. obtusus has three pores and O. apicalis hastwo) and in having a blunter snout. Ophichthus
obtusus is also similar to O. altipennis (Kaup,1856), a widely distributed Indo-Paci¿c species
known from western India, Malaysia, Indonesia,
Australia and Philippines to Japan, from 1–40 m
depth (McCosker and Randall, 2002). It is similar
in its dentition and head, tail, and body depth proportions, and both have a dark dorsal ¿n. HoweverO. obtusus has fewer vertebrae (O. altipennis has
a MVF 9/56/178, total vertebrae 172–182), a
blunter snout, and a low rather than an elevateddorsal ¿n.
Ophichthus obtusus is also similar to the widelydistributed eastern-Paci¿c species O. zophochir
Jordan and Gilbert 1882, found between 1–110 m
between northern California and Peru (McCosker
and Rosenblatt, 1998). They have a similar labial
barbel condition (both have a second barbel

Three New Species of Ophichthid Eels
Table 4. Counts and proportions (in thousandths)of the holotype (NSMT-P 106574) and 9 paratypes of Ophichthus obtusus sp. nov. (AMS I.
45673-001, BSKU 60521, BSKU 64546, BSKU
65078, BSKU 68429, BSKU 68432, BSKU
101341, CAS 231947, and NSMT-P 106575).
TL＝total length. HL＝head length.
Mean

Range

TL (mm)HL/TL
Head and trunk/TL
Tail/TL
Depth at gill opening/TL
Dorsal-¿n origin/TL
Pectoral-¿n length/HL
Upper jaw/HL
Snout/HL
Eye/HLInterorbital/HL
Gill opening/HL
Isthmus/HL
Predorsal vertebrae
Preanal vertebrae

—
88
429
571
31
112
310
230
180
88
162
109
250
11.4
55.3

540–697
84–92
417–449
551–583
27–35
106–120
272–330
187–270
138–211
62–104
133–186
85–130
214–287
11–19
52–57

Total vertebrae

150.8

148–153

beneath the orbit), similar head proportions anddentition, have a dark dorsal ¿n, and similar vertebral numbers (O. obtusus has a MVF 12/55/151,
total vertebrae 148–153 vs. O. zophochir with a
MVF 14/46/153, total vertebrae 149–162). They
differ in coloration (O. zophochir is gray dorsally, paler ventrally, and typically has black
median and pectoral ¿ns), somewhat in pectoral¿n length (O. zophochir has a longer pectoral¿n), and considerably in dentition (the jaw teethof O. zophochir are biserial).
Acknowledgments
We especially wish to thank Hirotoshi Asano(Kinki University) for supplying us with specimens and for his early assistance with this project. We also thank Jack Dumbacher (CAS) andNina Jablonski (Penn State University) for
advice concerning melanin; Patrice Pruvost(MNHN) for providing a radiograph of Ophichthus bonaparti; the late Eugenia Böhlke (ANSP)
for loaning us the syntypes of Ophichthus
stenopterus; Juliana Olsson and Claire Schneider
for the preparation of the illustrations; Hitoshi

15

Honda, Hideo Sakaji, and Kazuya Nashida (Fisheries Research Agency, Japan), the crew of R/V
Kotaka-maru (National Research Institute ofFisheries Science, Japan), Yoshihiko Machida(Professor Emeritus of Kochi University), Eri
Katayama, Naohide Nakayama, Shunsuke Yamamoto, and other BSKU members for collecting
specimens and various assistances; and Toshiyuki Ookawa (Kochi Prefecturel Fisheries Station) for assistance in taking radiographs. For
assistance with the transfer of specimens wethank: Mark McGrouther and Amanda Hay(AMS); Mysi Hoang and David Catania (CAS);
Hiroyuki Motomura (Kagoshima University);and Jeff Williams and Shirleen Smith (USNM).
We thank Kiyotaka Hatooka for his advice on
Japanese eels; and Keiichi Matsuura for assistance with this manuscript. Much of McCoskerʼs
participation in this project was accomplishedduring and following the 2010 Deep Sea Fish
Workshop held at the National Museum of
Nature and Science, Tokyo; he thanks Keiichi
Matsuura and Gento Shinohara for their kind
invitation. The second author thanks Yoshihiko
Machida for his generous advice during her thesis on snake eels from Tosa Bay at BSKU. The
study was supported in part by the grant-in-aid of
the Marine Science Project of the Natural Science Cluster, Sciences Unit, Kochi Univerisity.
Literature Cited
Asano, H. 1984. Ophichthidae. Pages 30–32, pls. 33–34,
338 in H. Masuda, K. Amaoka, C. Araga, T. Uyeno andT. Yoshino, eds. The ¿shes of the Japanese Archipelago. Tokai University Press, Tokyo.
Asano, H. 1987. A new ophichthid eel, Ophichthus megalops, from the Kumano-nada, Japan. Japanese Journalof Ichthyology, 34: 135–137.
Böhlke, E. B. 1982. Vertebral formulae of type specimensof eels (Pisces: Anguilliformes). Proceedings of the
Academy of Natural Sciences of Philadelphia, 134:
31–49.
Bonser, R. H. C. 1995. Melanin and the abrasion resistance of feathers. Condor, 97: 590–591.
Bonser, R. H. C. and M. S. Witter. 1993. Indentation hardness of the bill keratin of the European Starling, Sturnus vulgaris. Condor, 95: 736–738.
Castle, P. H. J. and J. E. McCosker. 1999. A new genus

16

J. E. McCosker, S. Ide and H. Endoand two new species of myrophine worm-eels, withcomments on Muraenichthys and Scolecenchelys(Anguilliformes: Ophichthidae). Records of the Australian Museum, 51: 113–122.
Eschmeyer, W. N. 2012. Catalogue of Fishes, electronic
version (23 January 2012). http//research.calacademy.
org/ichthyology/catalog/¿shcatmain.asp/
Franz, V. 1910. Die japanischen Knochen¿sche der Sammlungen Haberer und DoÀein. (Beiträge zur Naturgeschichte Ostasiens.) Abhandlungen der math.-phys.
Klasse der K. Bayer Akademie der Wissenschaften, 4(Supplement) (1): 1–135, Pls. 1–11.
Hatooka, K. 2002. Ophichthidae. Pages 215–225, 1456–
1459 in T. Nakabo, ed. Fishes of Japan with Pictorial
Keys to the Species, English edition. Tokai University
Press, Tokyo.
Ide, S. 2004. Taxonomic review of Ophichthidae from
Tosa Bay. Unpublished Masterʼs Thesis. Graduate
School of Sciences, Kochi University, Faculty of Natural Environmental Sciences. 127 pp. (In Japanese.)
Ide, S., Y. Machida and H. Endo. 2003. Coastal bottom¿shes collected by commercial trawlers from Tosa Bay
off Susaki, Southern Japan. Bulletin of Marine Sciencesand Fisheries, Kochi University, (22): 1–35. (In Japanese with English abstract.)
Kamohara, T. 1964. Revised catalogue of ¿shes of Kochi
Prefecture, Japan. Reports of the Usa Marine Biological Station, 11(1): 1–99.
Leviton, A. E., R. H. Gibbs, Jr., E. Heal and C. E. Dawson. 1985. Standards in herpetology and ichthyology:
part I. Standard symbolic codes for institutional
resources collections in herpetology and ichthyology.
Copeia (1985): 802–832.
McCosker, J. E. 1977. The osteology, classi¿cation, andrelationships of the eel family Ophichthidae. Proceedings of the California Academy of Sciences, Series 4,
41: 1–123.
McCosker, J. E. 2002. Notes on Hawaiian snake eels
(Pisces: Ophichthidae), with comments on Ophichthus
bonaparti. Paci¿c Science, 56: 23–34.
McCosker, J. E. 2010. Deepwater Indo-Paci¿c species ofthe snake-eel genus Ophichthus (Anguilliformes:
Ophichthidae), with the description of nine new spe-

cies. Zootaxa, 2505: 1–39.
McCosker, J. E., G. R. Allen, D. F. Hoese, J. E. Gates and
D. J. Bray. 2006. Ophichthidae. Pages 264–277 in D.F.
Hoese, D. J. Bray, J. R. Paxton and G. R. Allen, eds.
Fishes. Zoological Catalogue of Australia. Volume 35.
Australian Government Publishing Service, Canberra.
McCosker, J. E., E. B. Böhlke and J. E. Böhlke. 1989.
Family Ophichthidae. Pages 254–412 in E. B. Böhlke,ed. Fishes of the Western North Atlantic, Part 9, Volume 1, Memoirs of the Sears Foundation for Marine
Research, New Haven.
McCosker, J. E. and J. E. Randall. 2002. Ophichthys
melanochir Bleeker, 1865, A Junior Synonym of theHigh¿n Snake Eel Ophichthus altipennis (Kaup, 1856).
Copeia, 2002: 798–799.
McCosker, J. E. and R. H. Rosenblatt. 1998. A revision of
the eastern Paci¿c snake-eel genus Ophichthus(Anguilliformes: Ophichthidae) with the description of
six new species. Proceedings of the California Academy Sciences, 50: 397–432.
McGraw, K. J. 2005. The antioxidant function of many
animal pigments: are there consistent health bene¿ts ofsexually selected colourants? Animal Behaviour, 69:
757–764.
Randall, J. E. 2007. Reef and Shore Fishes of the Hawaiian Islands. University of Hawaiʼi, Honolulu. 546 pp.
Shinohara, G., H. Endo, K. Matsuura, Y. Machida and H.
Honda. 2001. Annotated checklist of the deepwater¿shes 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.
Sumida, S. and Y. Machida. 2000. Revision of the two
sympatric snake-eel species of the genus Ophichthus(Ophichthidae, Anguilliformes) from Tosa Bay, Southern Japan, with comments on O. tsuchidae. Bulletin ofMarine Sciences and Fisheries, Kochi University, (20):
51–69. (In Japanese with English abstract.)
Manuscript received 27 January 2012; revised 7 February2012; accepted 5 March 2012.
Associate editor: K. Matsuura