Bull. Natl. Mus. Nat. Sci., Ser. A, 35(4), pp. 227–232, December 22, 2009

Taxonomic Notes on the Rare Eelpout, Davidijordania lacertina(Perciformes, Zoarcidae)
Gento Shinohara1 and Ik-Soo Kim2
1

Department of Zoology, National Museum of Nature and Science,
3–23–1 Hyakunin-cho, Shinjuku-ku, Tokyo, 169–0073 Japan
E-mail: s-gento@kahaku.go.jp
2
Department of Biology, College of Natural Sciences, Chonbuk National University,Chonju, 560–756 Republic of Korea
E-mail: kim9620@chonbuk.ac.kr

Abstract Morphological characters of the rare eelpout, Davidijordania lacertina, were revised
based on a specimen collected from the Sea of Japan off South Korea in 1993. Davidijordania lacertina likely comprises a monophyletic group with Davidijordania poecilimon and Davidijordania
yabei in sharing an apomorphic condition: dark stripes on the head. The Korean specimen is thefirst occurrence from outside Russia for the species.
Key words : Zoarcidae, Davidijordania lacertina, morphology, Sea of Japan, South Korea.

Introduction
The zoarcid Davidijordania lacertina wasoriginally described by Pavlenko (1910) as Lycenchelys lacertinus on the basis of three syntypes from Peter the Great Bay. The genus Davidijordania was established for the species byPopov (1931). According to Anderson and Fedorov (2004), this genus contains the following
four species: Davidijordania brachyrhyncha(Shmidt, 1904), Davidijordania jordaniana
Schmidt, 1936, Davidijordania poecilimon (Jordan and Fowler, 1902) and D. lacertina. Recently, Anderson and Imamura (2008) described Davidijordania yabei based on 11 specimens fromJapan and Russia. All species except for D. poecilimon are very rare (Sokolovskaya et al., 1998;
Fedorov et al., 2003) and the genus is in need ofrevision (Anderson and Fedorov, 2004). Especially, detailed morphological data of the typespecies (D. lacertina) has been lacking.
Schmidt (1936) added Vladimir Bay (Russia)
to the distribution of D. lacertina, but did notgive detailed specimen data. Except for threesyntypes (whereabouts unknown, see Andersonand Fedorov, 2004), two additional specimens(69 and 170 mm in total length: TL) were reported from Peter the Great Bay (type locality)
by Lindberg and Krasyukova (1975). Recently,Balanov et al. (2006) reported two specimens(140–157 mm TL) from Peter the Great Bay andbriefly described some morphological characters.
In 1993, a single specimen of D. lacertina wascollected from the Sea of Japan off the Korean
Peninsula near the border between the Republicof Korea and the Democratic People’s Republicof Korea. We herein describe the external and internal morphologies of this specimen.
Materials and Methods
The specimen examined here is deposited in
the Department of Biology, College of NaturalSciences, Chonbuk National University, Republicof Korea (CNUC); comparative specimens in theHokkaido University Museum, Hakodate(HUMZ), the National Museum of Nature andScience, Tokyo (NSMT) and the National
Musuem of Natural History, Smithsonian Institution (USNM). Counts were made from radi-228

Gento Shinohara and Ik-Soo Kimographs, and measurements with digital caliper
to the nearest 0.1 mm following Anderson(1982). Standard length (SL) and head length(HL) are used throughout.
Osteological characters were observed fromboth radiographs and three-dimensional skull images constructed from X-ray CT scanning equipment for laboratory animals (LCT-100; Aloka,Tokyo).
Systematic Accounts
Order Perciformes
Suborder Zoarcoidei
Family Zoarcidae
Davidijordania lacertina (Pavlenko, 1910)[New Korean name: Kin-munzagalchi][Japanese name: Naga-sarasagaji](Figs. 1–4, Table 1)
Lycenchelys lacertinus Pavlenko, 1910: 53, figs. 10–11(original description, Peter the Great Bay); Soldatov
and Lindberg, 1930: 499.
Davidojordania lacertina [sic]: Schmidt, 1936: 99 (Peterthe Great Bay and Vladimir Bay); Lindberg andKrasyukova, 1975: 174, fig. 135 (keys, description,Peter the Great Bay).
Davidijordania lacertina: Matsubara, 1955: 780 (key);
Toyoshima, 1984: 305; Andrianov and Kussakin, 1998:327 (list); Sokolovskaya et al., 1998: 7 (list); Andersonand Fedorov, 2004: 4, 43 (list); Balanov et al., 2006:
256 (description, Peter the Great Bay).

Material examined. CNUC 34536, 1 specimen, male, 161.5mm SL (25.9 mm HL), Sea ofJapan off Mukho-dong Donhae City, Kanwon-do,
South Korea (37°31N, 129°02E), April 1993
(date unknown).
Description. Because tail tip is broken, standard and total lengths cannot be measured. Predorsal length about equal to HL (101.5% HL);
prepectoral length slightly larger than HL(103.1%); preanal length slightly smaller thantwice of HL (196.9%). Proportions in HL: body
depth 40.9% at pelvic fin origin and 27.4% atanal fin origin; prepelvic fin length 88.0%; snoutlength 24.3%; eye diameter 18.9%; interorbital
width 3.9%; gill slit length 24.3%; upper jaw

Table 1. Counts and proportional measurements ofDavidijordania lacertina from South Korea andRussia.
CNUC 34536

Balanov et al.
(2006)n1n2SL (mm)161
CountsPrecaudal vertebrae
22
Caudal vertebrae
94
Total vertebrae
116
Pectoral fin rays
17Pelvic fin rays
3
Pseudobranch filaments4Vomerine teeth
4
Palatine teeth
13–14
Nasal pores
2
Interorbital pores
1
Suborbital pores
7
Postorbital pores
4
Occipital pores
2
Mandibular pores
4
Preopercular pores
4
Proportional measurements (% HL)
Snout length
24.3
Eye diameter
18.9
Upper jaw length
48.7
Gill slit length
24.3

138–154
2298
120
15–16
3
4–5
3
10–11
2
1
6–7
4–5
3
4
4
24.4–24.8
20.5
45.4–46.7
4.4–28.6

length 48.7%; postorbital head length 55.7%;
pectoral fin length 55.6%; pelvic fin length
63.3%. Vertebrae more than 116 [22 (abdominal vertebrae)more than 94 (caudal)]; dorsal fin
rays more than 108 (last ray remains on 89th caudal vertebra); anal fin rays more than 90 (last rayremains on 90th caudal vertebra); pectoral fin
rays 17; pelvic fin rays 3; gill rakers 11911; pseudobranch filaments 4; pyloric caeca 2,nub-like. Body elongate, compressed laterally,cross section elliptical. Scales absent on head,nape and fin membranes, but present on body including abdomen. Dorsal fin origin above posterior end of opercle. Opercular flap at upper margin of gill slit well developed. Pectoral fin origin
at about level of body midline. Posterior marginof pectoral fin almost rounded. Pelvic fins present. Lateral line mediolateral, incomplete, ends
in anterior part of abdomen. Head large, its dorsal profile convex at snout. Nostril tube small,
not reaching upper lip when pressed forward.

Taxonomy of Davidijordania lacertina

Fig. 1.

229

Davidijordania lacertina, CNUC 34536, 161mm SL, from the Sea of Japan off Korea.

Mouth large, posterior end of upper jaw extending beyond a vertical line through posterior endof pupil. Eye ovoid, not entering dorsal profile ofhead. Interorbital space narrow, flattened. Gill slitwide, extending below a horizontal between 14thand 15th pectoral fin rays. Both jaws with enlarged conical teeth; anterior teeth in a patch,others in a single row. Four teeth on vomer; 14teeth on palatine (13 in right). Head pores small,rudimentary: nasal pores 2; interorbital pore 1;
suborbital pores 7; postorbital pores 4; occipitalpores 2; preoperculomandibular pores 8.
Coloration in preservative. Dark stripes on
dorsal and lateral surface of head (Figs. 1–2).
Anterior 1/3 of upper lip heavily pigmented ventrally; anterior tip of lower lip slightly pigmented.
Ventral midline and adjacent areas of head withdark pigment. Ventral half of body with isolatedgroups of large dark spots in which 3 form an
angle and sometimes fused to one another.
Osteology. Six suborbital bones present, forming semicircle around eye, the first largest andplate-like, the others tube-like. Premaxilla comprising a short ascending process and long,
dentigerous premaxillary process (Fig. 3). Maxilla long and robust. Retroarticular firmly attached
to anguloarticular. Mesopterygoid attached to ectopterygoid and separated from metapterygoid
and quadrate. Metapterygoid with a notch forsymplectic dorsoposteriorly. Metapterygoid articulating with hyomandibula and symplectic posteriorly. Hyomandibula with three articular heads
dorsally, anterior two attached to neurocranium
and posteriormost to opercle and not elongate.
Preopercle crescent-shaped, with 3 pores (preoperculomandibular pores 6–8 in Fig. 2) opening
from interior canal; 4 pores (preoperculomandibular pores 1–4) arising from dentary and1 (pore 5) from anguloarticular. Opercle triangular. Ceratohyal-epihyal juncture smooth. Branchiostegal rays 426, anterior 4 on ceratohyal
and remainder on epihyal. Posttemporal long,ventral ramus weak.
Remarks. The specimen can be identified as D.

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Gento Shinohara and Ik-Soo Kim

Fig. 2. Head pores and pigmentation of Davidijordania lacertina, CNUC 34536. IO, interorbital pore; NS, nasal
pores; OC, occipital pores; PO, postorbital pores; SO, suborbital pores. Numbers indicate preoperculomandibular pores.

Taxonomy of Davidijordania lacertina

Fig. 3. CT scanning images of Davidijordania
lacertina, CNUC 34536. Top, dorsal view;
middle, left side of lateral view; bottom, rightside of lateral view.

lacertina in having the following characters:
snout length more than eye diameter; ventral halfof body with isolated groups of large dark spots
in which 3 form an angle and sometimes fused to
one another.
Although Lindberg and Krasyukova (1975)
showed an illustration of a specimen of D. lacertina without dark stripes or dark blotches on
the head, Pavlenko’s original description (Fig. 4)
showed that this species had the bands andblotches as shown in the present specimen.
Toyoshima (1984) mistakenly described characters of this species as “[c]heek without band-likeblotches” based on the illustration of Lindberg
and Krasyukova (1975), followed by Hatooka(2002). Balanov et al. (2006) reported the dark
stripes on the head of their specimens, too.
Our specimen is different from the specimensof Balanov et al. (2006) in having only 2 occipital pores (vs. 3), but a left pore is abnormally absent (Fig. 2). Although the Korean specimen has231

Fig. 4. Dorsal view of Davidijordania lacertina.
From Pavlenko (1910: fig. 10).

slightly higher counts in pectoral fin rays andpalatine teeth (Table 1), this is intraspecificallyvariable in zoarcids (see Anderson, 1982, 1994).
There are two morphological groups in the 5
species of Davidijordania (Anderson and Imamura, 2009). Group 1 (sensu Anderson and Imamura, 2008) containing D. brachyrhyncha and D.
jordaniana, is defined by less than 110 vertebrae
and slightly restricted gill slit. Group 2 (sensuAnderson and Imamura, 2008) containing D. lacertina, D. poecilimon and D. yabei, is defined bymore than 112 vertebrae and large gill slit. In addition to these characters, dark stripes on thehead separate Group 2 from Group 1. Group 2 islikely monophyletic because dark bands on thehead are rare and may be apomorphic among thesubfamily Gymnelinae (sensu Anderson, 1994)
which includes Davidijordania.
Because D. lacertina is distributed in the Seaof Japan, the species is cited in books and treated232

Gento Shinohara and Ik-Soo Kim

inclusive of the ichthyofauna and/or keys ofJapanese fishes (e.g., Matsubara, 1955; Toyoshima, 1984), there are no collection records
from Japanese waters (Hatooka, 2002). The Korean specimen is the first occurrence outside
Russia for the species.
Comparative materials examined. Davidijordania brachryncha: HUMZ 70868, 1 specimen,
123 mm SL mm SL, Sea of Okhotsk (55°32'N,137°37.5E), 24 July 1917; Davidijordania jordaniana: USNM 92585, 1 specimen, 129.5 mm
SL, Sea of Okhotsk, 1912 (date and month unknown); Davidijordania poecilimon: NSMT-P64996, 1 specimen, 153.5 mm SL, Pacific coast
off Honshu Island, Japan (36°30.9N,140°59.6E–36°29.4N, 140°58.5E), 250 m
depth, 18 April 1996.
Acknowledgments
We express sincere thanks to M. Eric Anderson (South African Institute of Aquatic Biology)
for critical reading of a draft manuscript and providing English language corrections. Our special
thanks go to Jeffrey T. Williams (USMN) andKazuhiro Nakaya, Mamoru Yabe and Hisashi
Imamura (HUMZ) for comparative specimens.
This study was partially supported by the Core
University Program between the Japan Society
for the Promotion of Science (JSPS) and the Korean Science and Engineering Foundation(KOSEF).
References
Anderson, M. E., 1982. Revision of the fish genera Gymnelus Reinhardt and Gymnelopsis Soldatov (Zoarcidae),with two new species and comparative osteology ofGymnelus viridis. National Museums of Canada Publi-cation in Zoology, (17): i–iv1–76.
Anderson, M. E., 1994. Systematics and osteology of theZoarcidae (Teleostei: Perciformes). JLB Smith Instituteof Ichthyology, Ichthyological Bulletin, 60: 1–120.
Anderson, M. E. and V. V. Fedorov, 2004. Family Zoarcidae Swainson 1839. California Academy of Science Annotated Checklist of Fishes, 34: 1–58.
Anderson, M. E. and H. Imamura, 2008. Two new gymneline eelpouts (Perciformes: Zoarcidae) from Hokkaido,
Japan. Bulletin of the National Museum of Nature andScience, Series A (Zoology), Supplement 2: 59–67.
Andrianov, A. V. and O. G. Kussakin, 1998. A check listof biota of the Peter the Great Bay the Sea of Japan.
349 pp. Dalnauka, Vladivostok. (In Russian.)
Balanov, A. A., D. V. Antonenko and D. V. Izmyatinsky,
2006. New records of fish species for Peter the Great
Bay, Sea of Japan. Russian Journal of Marine Biology,
32: 255–258.
Fedorov, V. V., I. A.Chereshnev, M. V. Nazarkin, A. V.
Shestakov and V. V. Volobuev, 2003. Catalog of marine
and freshwater fishes of the northern part of the Sea ofOkhotsk. Dalnauka, Vladivostok. (In Russian withEnglish abstract.)
Hatooka, K., 2002. 287. Zoarcidae eelpouts. In: Nakabo,T. (ed.) Fishes of Japan with Pictorial Keys to theSpecies, English Edition. pp. 1028–1044, 1581–1583.
Tokai University Press, Tokyo.
Matsubara, K., 1955. Fish morphology and hierarchy, PartI. xviii789 pp. Ishizaki-shoten, Tokyo. (In Japanese.)
Pavlenko, M. N., 1910. Ryby Zaliva Petr Velikii [Fishes ofPeter the Great Bay]. Trudy Obshchestva Estestvoispytateley pri Imperatorskomy Kazanskomy Universitety,
42: 1–95. (In Russian.)Popov, A. M., 1931. On a new genus of fish Davidijordania (Zoarcidae, Pisces) from the Pacific. Comptes Rendus de l’Académie des Sciences de l’URSS, 1931:210–215. (In Russian with English abstract.)
Schmidt, P. J., 1936. On the two genera Davidojordania
Popov and Bilabria n. (Pisces, Zoarcidae). ComptesRendus (Doklady) de l’Academie des Science del’URSS, 1: 97–200.
Toyoshima, M., 1984. Family Zoarcidae eelpouts. In: Masuda H., K. Amaoka, C. Araga, T. Uyeno and T. Yoshino(eds.), The Fishes of the Japanese Archipelago, English
Text, pp. 304–309. Tokai University Press, Tokyo.