Bull. Natl. Mus. Nat. Sci., Ser. A, Suppl. 6, pp. 33–40, March 30, 2012

Careproctus rausuensis, a New Liparid Fish (Percomorphacea:
Cottiformes), Collected from Hokkaido, Japan
Keisuke Machi1, Takahiro Nobetsu2 and Mamoru Yabe3
1

Toyama Prefectural Agricultural, Forestry & Fisheries Research Center Fisheries Institute,
364 Takatsuka, Namerikawa, Toyama 936–8536, Japan
E-mail: keisuke.machi@pref.toyama.lg.jp
2
Shiretoko Nature Foundation, 531 Iwaobetsu, Shari-chou, Hokkaido 099–4356, Japan
E-mail: nobe@shiretoko.or.jp
3
Laboratory of Marine Biology and Biodiversity (Systematic Ichthyology),
Research Faculty of Fisheries Sciences, Hokkaido University,
Hakodate, Hokkaido 041–8611, Japan
E-mail: myabe@¿sh.hokudai.ac.jp

Abstract A new liparid ¿sh, Careproctus rausuensis, is described on the basis of 35 specimens(54.0–164.3 mm in standard length: SL) collected by deep-sea water pumps set at 356 m depth off
Hokkaido, Japan (Rausu Fishing Port, Shiretoko Peninsula). It is distinguished from known congeners by the following combination of characters: tips of the anterior dorsal- and anal-¿n rays
extending beyond distal margin of each ¿n membrane, head wide, its width 21.6–28.4% SL, gillslit long, reaching to 7–11th pectoral-¿n rays, chin pore single, dorsal-¿n rays 50–54, pectoral-¿nrays 34–37, vertebrae 56–59, pectoral radials 4 (3＋1), round, and lower pectoral lobe shorter thanthe upper one.
Key words: Liparidae, Careproctus rausuensis, new species, deep-sea water pump, Shiretoko
Peninsula, Japan.

The genus Careproctus Krøyer, 1862 is one of
the species-rich groups in the Laparidae, including over 100 species (Chernova et al., 2004).
According to Burke (1930) and Kido (1988),
Careproctus is diagnosed by the following characters: disk present, nostril single, pseudobranchiae absent, and pectoral-¿n with less rays thananal-¿n. Nakabo (2002) recognized 19 species of
Careproctus from Japan and adjacent waters. In
addition, three species of Careproctus (Careproctus
parvidiscus Imamura and Nobetsu, 2002, C.
rotundifrons Sakurai and Shinohara, 2008 and
C. notosaikaiensis Kai et al., 2011) were describedfrom Japan. Nobetsu et al. (1998) listed 7 speciesof Careproctus from the Shiretoko Peninsula andadjacent waters, Hokkaido, Japan (e. g., C. colletti
Gilbert, 1895, C. cyclocephalus Kido, 1983,
C. mederi Schmidt, 1915, C. rastrinus Gilbert
and Burke, 1912, C. roseofuscus Gilbert andBurke, 1912), and suggested that more species
should be still present around the Shiretoko Peninsula.
Three deep-sea water pumps capturing deepsea water for the local industries (e. g., for thematerial of drinking, for cooling ¿sh) in Rausu,
Shiretoko Peninsula were set up at 356 m depth
about 2.8 km (44°00.09ƍN, 145°14.01ƍE) from
Rausu Fishing Port, in the Nemuro Straits connecting the Sea of Okhotsk and the Paci¿c
Ocean. While pumping up deep-sea water, many
¿shes were collected as impurities (e. g., Malacocottus zonurus Bean, 1890, Careproctus macrodiscus Schmidt, 1937, C. mederi, C. rastrinus,
C. roseofuscus, Liparis ochotensis Schmidt,
1904). Recently, 35 specimens of a uniqueliparid ¿sh were pumped up. These specimens
were classi¿ed into the genus Careproctus
Krøyer, 1862 owing to the following diagnostic

34

K. Machi, T. Nobetsu and M. Yabe

characters of this genus: snout without barbels, a
single nostril, presence of disk and pleural ribs,
pectoral-¿n rays fewer than anal-¿n rays (Burke
1930; Stein, 1978; Kido 1988; Orr and Maslenikov, 2007). Within the genus, this species
resembles C. cyclocephalus Kido 1983, C. comus
Orr and Maslenikov, 2007, C. homopterus Gilbert and Burke, 1912, and C. sinensis Gilbert andBurke, 1912 in having similar ¿n ray counts ofthe dorsal, anal and pectoral ¿ns, but differs fromthem in having the unique morphology in the
distal margin of the dorsal and anal ¿ns. We
herein describe it as a new species of the genus
Careproctus.
Materials and Methods
Counts, measurements, and terminology follow Andriashev and Stein (1998), except for the
lower lobe of pectoral ¿n following Kido (1988).
Cephalic pores are shown as a series as describedby Burke (1930): nasal-mandibular-maxillarysuprabranchial series. Counts of vertical ¿n rays,
vertebrae, and pleural ribs are based on radiographs. Standard and head lengths are expressed
as SL and HL, respectively. Although the family
Liparidae was previously included in the order
Scorpaeniformes, we follow Wiley and Johnson(2010) in placing it in the order Cottiformes.
Specimens examined in this study are depositedin the Fisheries Science Center, Hokkaido University Museum, at Hakodate (HUMZ), Department of Zoology, National Museum of Natureand Science, Tsukuba (NSMT), and the National
Museum of Natural History, Washington, D.C.
(USNM).
Careproctus rausuensis sp. nov.
(New Japanese name: Tama-Konnyaku-uo)(Figs. 1–3, Tables 1, 2)

Holotype. HUMZ 202085, 146.0 mm SL,
female, 29 Sep., 2007, 44°00.09ƍN, 145°14.01ƍE,
the Nemuro Straits, about 2.8 km distant from
Rausu ¿shing port, Paci¿c coast of Shiretoko
Peninsula, Hokkaido, Japan, 356 m depth, col-lected by deep-sea water pump.
Paratypes. 34 specimens, 54.3–164.3 mm SL.
HUMZ 202086, 106.1 mm SL, female, 2 Oct.
2007; HUMZ 203619, 59.5 mm SL, female, 25
Feb. 2008; HUMZ 203635, 137.8 mm SL,
female, 5 Feb. 2008; HUMZ 203638, 92.6 mm
SL, female, 22 June. 2008; HUMZ 203640,
164.3 mm SL, female, 21 July. 2008; HUMZ
203644, 88.0 mm SL, male, 14 Feb. 2008;
HUMZ 203647, 136.2 mm SL, female, 1 Aug.
2008; HUMZ 203783, 56.0 mm SL, male, 5 Dec.
2008; HUMZ 203786, 106.8 mm SL, female, 26
Sep. 2008; HUMZ 203804, 74.8 mm SL, sex
unknown, 12 Feb. 2008; HUMZ 203815,
161.2 mm SL, female, 20 Oct. 2008; HUMZ
203822, 108.0 mm SL, male, 13 Nov. 2008;
HUMZ 203828, 135.0 mm SL, male, 27 Oct.
2008; HUMZ 203836, 54.3 mm SL, male, 22
Oct. 2008; HUMZ 203839, 84.0 mm SL, female,
19 Aug. 2008; HUMZ 203840, 79.5 mm SL,
female, 10 Sep. 2008; HUMZ 203850, 54.0 mm
SL, male, 4 Sep. 2008; HUMZ 203855, 97.2 mm
SL, male, 19 Sep. 2008; HUMZ 204741,
107.0 mm SL, female, 19 Dec. 2008; HUMZ
204747, 111.8 mm SL, male, 16 Jan. 2009 (dissected); HUMZ 204756, 81.3 mm SL, female, 14
April. 2009; HUMZ 204768, 62.2 mm SL,
female, 18 Jan. 2009; HUMZ 204776, 112.0 mm
SL, male, 10 Jan. 2009; HUMZ 204791,
58.8 mm SL, female, 31 Dec. 2008; HUMZ
205645, 71.4 mm SL, male, 3 June. 2008;
HUMZ 205764, 92.0 mm SL, female, 11 June.
2009. NSMT-P 106564, 120.8 mm SL, male, 20
Nov. 2007; NSMT-P 106565, 114.9 mm SL,
female, 7 Jan. 2008; NSMT-P 106566, 91.0 mm
SL, female, 19 Nov. 2007; HUMZ 202110,
73.1 mm SL, female, 7 Jan. 2008; NSMT-P
106567, 58.7 mm SL, male, 28 Sep. 2007;
NSMT-P 106568, 151.4 mm SL, male, 20 Feb.
2008; USNM 404475, 114.9 mm SL, female, 4Sep. 2008; USNM 404476, 125.0 mm SL, male,
15 Jan. 2008.
Diagnosis. A species of Careproctus diagnosed by the following characters: dorsal-¿n rays
50–54 (mode 53); anal-¿n rays 44–48 (mode 47);
pectoral-¿n rays 34–37, caudal-¿n rays 10–11,

New Liparid from Japan

35

Fig. 1. Lateral view of Careproctus rausuensis sp. nov., collected from the western North Paci¿c. A: holotype, HUMZ
202085, 146.0 mm SL; B: paratype, HUMZ 203804, 74.8 mm SL. Bars 10 mm.

vertebrae 56–59. Pectoral radials 4 (3＋1),
round. Head width 22.6–28.4 % SL. Teeth trilobed. Gill slit long, reaching to 7–11th pectoral¿n ray. Lower pectoral ¿n lobe shorter than theupper lobe. Tips of anterior dorsal- and anal-¿nrays extending beyond distal margin of ¿n membranes.
Description. Data for the holotype are shown¿rst, followed by data for paratypes in parentheses if different. Frequency distributions of counts
are shown in Table 1.
Dorsal-¿n rays 50 (50–54), anal-¿n rays 45(45–48), pectoral-¿n rays 6＋29＝35 (5–6
＋29–31＝34–37), caudal-¿n rays 10 (10–11),
vertebrae 11＋45＝56 (10–11＋46–48＝56–59),
preural ribs 2, gill rakers 14 (observed in only
HUMZ 204747), pyloric caeca 25 (24–28),
epural 1.
Proportional measurements: head length 32.1

(26.7–38.8) %SL, head width 28.4 (22.6–27.4)%SL, body depth 31.7 (20.8–31.5) %SL, predorsal length 36.6 (27.4–37.8) %SL, preanal length47.9 (37.9–49.4) %SL, distance between snout
and disk 21.9 (14.9–24.0) %SL, distance
between snout and anus 32.2 (23.5–31.4) %SL,
distance between mandible and disk 20.9 (14.2–
21.0) %SL, distance between mandible and anus
29.6 (23.1–29.2) %SL.
Snout length 30.5 (25.6–35.6) %HL, eyediameter 19.2 (16.5–28.9) %HL, orbit diameter
26.2 (22.4–34.5) %HL, interorbital width 43.1
(32.5–48.7) %HL, bony interorbital width 28.6
(20.6–33.0) %HL, postorbital distance 48.8
(37.2–56.4) %HL, gill opening length 30.7
(20.4–39.2) %HL, upper jaw length 43.5 (30.7–
46.1) %HL, lower jaw length 44.6 (29.7–43.3)%HL, upper lobe of pectoral-¿n length 59.3
(42.1–67.6) %HL, lower lobe of pectoral-¿n

36

K. Machi, T. Nobetsu and M. Yabe

Fig. 2. Careproctus rausuensis sp. nov., holotype, HUMZ 202085, 146.0 mm SL: dorsal view (A), mandible and disk
(B, ventral view), premaxillary teeth (C, ventral view), and anterior dorsal-¿n membrane (D, picked up by a tweezers). Bars 10 mm in A and B, 0.1 mm in C, and 1 mm in D.

length 49.5 (33.9–54.1) %HL, caudal-¿n length29.0 (20.2–41.6) %HL, disk length 19.6 (16.5–
25.1) %HL.
Body weakly compressed, deepest at nape,tapering to caudal ¿n. Head extremely wide andheavy; upper pro¿le descending slowly to snout;
width almost equal to its depth. Snout short,deep. Eye large; pupil round. Nostril opening on
horizontal level between central and upper margins of eye. Nostril tube short. Mouth small, horizontal, maxilla extending just below anterior
margin of eye. Teeth small, trilobed, arranged in
6–9 oblique rows in upper jaw, and in 5–8
oblique rows in lower jaw. Outer teeth weakly
trilobed, smaller than inner teeth. Cephalic sensory pores large, its pore pattern 2-6-7-2. Anteriormost mandibular pore single, both canals opening into a single pore. Gill opening moderately
large, upper margin at level of mid-orbit, extending to ventrally to 11th pectoral-¿n ray (7–11th

in paratypes). Gill rakers short, triangular, covered with ¿ne spines (in HUMZ 204747). Opercular Àap supported by two spines extending horizontally, tip of upper spine on level with lower
margin of eye.
Dorsal ¿n originating above gill opening. Anal¿n originating below base of 9th dorsal-¿n ray(7–9th). Caudal ¿n narrow, continuous with dorsal and anal ¿ns for about half its length. Pectoral¿n shallowly notched, uppermost ¿n ray on level
between lower margin of eye and posterior corner of maxilla. Upper lobe of pectoral ¿n slightly
not reaching a vertical through origin of anal ¿n(reaching 1–4 anal-¿n ray in some paratypes).
Lower lobe of pectoral ¿n short, reaching anus in
the holotype (between the posterior portion of
disk and anus in some paratypes), about the half
length of rays free from ¿n membrane. Symphysis of lower lobe of pectoral ¿n below posterior
portion of eye. No gelatinous layer in dorsal- andNew Liparid from Japan
Table 1.

Frequency distributions of counts in Careproctus rausuensis sp. nov.

Dorsal-¿n raysn

Anal-¿n rays

Pectoral-¿n rays

50

51

52

53

54

55

45

46

47

48

33

34

35

36

37

1*

1

5

10

5

1

3*

7

10

3

2

4

7*

8

12

Caudal-¿n rays
10
n

37

Pyloric caeca

11

11*

4

Gill opening

24

25

26

27

28

6

7

8

9

10

11

4

6*

7

3

3

2

9

9

8

3

2*

Vertebrae
AbdominalnCaudal

Total

10

11

45

46

47

48

56

57

58

59

5

18*

1*

1

12

9

2*

3

10

8

* holotype.

Fig. 3. Lateral views of pectoral girdle (A, left side) and caudal complex (B, right side) of Careproctus rausuensis sp.
nov., paratype, HUMZ 204747, 111.8 mm SL. c, coracoid; r, radial; s, scapula; e, epural; hs, haemal spine; lhp, lower
hypural plate; pc1, preural centrum 1; pc2, preural centrum 2; ph, parhypural; uhp, upper hypural plate. Bars 10 mm
in A and 1 mm in B.

anal-¿n membranes (weak layer in some paratypes). Tips of all dorsal- and anal-¿n rays soft,
free from ¿n membrane (Fig. 2D). Disk small,Àat, round with wide and thin margin, its diameter about equal to eye diameter. Posterior marginof disk situated below posterior margin of preopercle. Anus situated almost below posterior
margin of opercular Àap, separated from disk by
a space equal to orbit diameter. Stomach small,pyloric caeca long, slender. Skin smooth andthick, lacking prickles. Gelatinous tissue thinbeneath skin. Male with short and conical genital
papilla.
Abdoninal vertebrae 11 (10–11). Caudal skeleton composed of two elements separated by anarrow slit: upper hypoural plate and lower

hypural plate＋parhypural (Fig. 3B).
Pectoral radials four (3＋1), round, unnotched(Fig. 3A), with no fenestra. No distal radials.
Scapula with strong helve. Coracoid triangularwith broad lamina.
Color. Color in alcohol: body pale pinkish,caudal ¿n and posterior portions of dorsal andanal ¿ns black. Nostril, iris, and lips pale. Anterior margin of both jaws with black pigments.
Orobranchial cavities pale. Peritoneum andpyloric caeca pale. Stomach black. Color whenfresh (HUMZ 203804, Fig. 1B): body dark reddish, caudal ¿n and posterior portions of dorsal
and anal ¿ns black.
Distribution. Known only from the type locality
in the western North Paci¿c off Hokkaido, Japan

38

K. Machi, T. Nobetsu and M. Yabe

(Rausu, Shiretoko Peninsula), 356 m depth.
Etymology. The name rausuensis is in reference to the type locality, Rausu, a town on the
Paci¿c coast of the Shiretoko Peninsula, Hokkaido, Japan.
Comparison. Within the genus Careproctus, C.
rausuensis most resembles C. cyclocephalus
Kido 1983, known from the southern Okhotsk
Sea, in having a greater head length (26.7–38.8%
SL in C. rausuensis vs. 25.7–29.9% SL in C.
cyclocephalus), similar numbers of dorsal- andanal-¿n rays (50–54 and 44–48 vs. 54–57 and
47–51), and dark reddish body color. However,C. rausuensis differs from the latter in having

more pectoral-¿n rays (34–37 in C. rausuensis
vs. 26–31 in C. cyclocephalus), fewer pyloric
caeca (24–28 vs. 33–50), tooth form (trilobed vs.
canine), shorter lower lobe of pectoral ¿n (33.9–
54.1% HL vs. 84.5–126.6% HL), and larger headwidth (Fig. 4). Although C. rausuensis resembles
C. comus Orr and Maslenikov, 2007, C. homopterus Gilbert and Burke, 1912, and C. sinensis
Gilbert and Burke, 1912 in having similar ¿n ray
counts of dorsal, anal, and pectoral ¿ns, it differsfrom the latter three species in having a wider
head width, and from C. homopterus and C.
sinensis in having gill openings extending farther
ventrally (Table 2) (Gilbert and Burke, 1912;

Fig. 4. Relationship between standard length (SL) and proportion of head width (% SL) for Careproctus rausuensis sp.
nov. (holotype, solid circle; paratypes, open circles) and C. cyclocephalus (open squares).

Table 2.

Comparisons of Careproctus rausuensis sp. nov. and three species of genus Careproctus.

Measurements% of SL
Head width
Counts
Dorsal-¿n rays
Anal-¿n rays
Pectoral-¿n rays
Gill opening

C. rausuensis

C. comusC. homopterus

C. sinensis

22.6–28.4

7.4–15.6

14.0

13.2

50–54
45–48
34–37
7–11

50–56
44–50
33–39
0–5

55
49
32–34
0

53
47
33
1

Data of C. comus from Orr and Maslenikov (2007), C. homopterus and C. sinensis from Kido (1988).

New Liparid from Japan

Kido, 1988; Orr and Maslenikov, 2007). Furthermore, C. rausuensis is clearly distinguished fromall known congeners by having the tips of rayson the anterior parts of the dorsal and anal ¿ns
extending beyond the distal margin of each ¿nmembrane (Fig. 2D). Although this character has
been regarded as a diagnosis of genus Allocareproctus Pitruk and Fedorov, 1993, C. rausuensis
lacks other diagnostic characters of Allocareproctus: i.e. anterior dorsal-¿n rays spiny, small
papillae present on some pores of cephalic sensory system, an extremely large disk (30.0–
45.0% HL), and a gill slit entirely above the pectoral ¿n (Pitruk and Fedorov, 1993; Orr andBusby, 2006).
It is similar to the following North Paci¿c species, Careproctus simus Gilbert, 1896, C. bowersianus Gilbert and Burke, 1912, C. attenuates
Gilbert and Burke, 1912, C. mollis Gilbert andBurke, 1912, C. opistotremus Gilbert and Burke,
1912, C. faunus Orr and Maslenikov, 2007, andC. rotundifrons Sakurai and Shinohara, 2008, by
having similar counts and three-lobed teeth, butdiffers from all of them by having longer gill slit
(reaching to 7–10th pectoral-¿n base vs. 1–5th)and single chin pore (Gilbert and Burke, 1912;
Mecklenburg et al., 2002; Orr and Maslenikov,
2007; Sakurai and Shinohara, 2008).
Comparative materials. Careproctus cyclocephalus: Holotype: HUMZ 77754, 267.1 mm
SL, female, 44°27ƍN, 144°26.5ƍE, 930–950 m
depth. Paratype: HUMZ 70923, 226.3 mm SL,
44°12ƍN, 144°54ƍE, 750 m depth. Non types: 17
specimens (HUMZ 77613, 77947, 78743, 78865,
78867, 78868, 78898, 79699, 79701, 79702,
79706, 79719–79721, 124057, 126054 and
126082, 140.4–254.3 mm SL, southern OkhotskSea).
Acknowledgments
We express our sincere thanks to T. Watanabeand H. Yamaishi (Rausu Town Of¿ce), Rausu¿shermanʼs cooperative, and A. Yamaguchi(Hokkaido University), for providing many samples collected by the deep-sea water pump of39

Rausu, and to J. W. Orr (U. S. National Marine
Fisheries Service, Alaska Fisheries Science Center) and H. Imamura (Hokkaido University) for
critically reading an early draft of the manuscript
and providing important comments.
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Manuscript received 27 July 2011; revised 10 December
2011; accepted 14 February 2012.
Associate editor: K. Matsuura