Platax 14: 46-54, 2017

Record of a flathead fish, Rogadius pristiger(Cuvier, 1829) (Platycephalidae) from Taiwan
Katsuya Kimura1*, Megumi Takagishi1, Toshio Kawai2, Hisashi
Imamura2,3, Hsuan-Ching Ho4, Taketeru Tomita5, Fumiya Tanaka6 andGento Shinohara7,8
1

Laboratory of Marine Biology and Biodiversity (Systematic Ichthyology), Graduate School of Fisheries
Sciences, Hokkaido University, 3–1–1 Minato-cho, Hakodate, Hokkaido 041–8611, Japan

2

Fisheries Science Center, The Hokkaido University Museum, 3–1–1 Minato-cho, Hakodate, Hokkaido
041–8611, Japan3Laboratory of Marine Biology and Biodiversity (Systematic Ichthyology), Faculty of Fisheries Sciences,Hokkaido University, 3–1–1 Minato-cho, Hakodate, Hokkaido 041–8611, Japan

4

National Museum of Marine Biology and Aquarium, no. 2, Houwan, Checheng, Pingtung 944, Taiwan

5

Okinawa Churashima Research Center, Okinawa Churashima Foundation, 888 Motobu, Okinawa
905–0206, Japan

6

National Research Institute of Far Seas Fisheries, Japan Fisheries Resedrch and Education Agency, 5–7–1
Orido, Shimizu ward, Shizuoka 424–8633, Japan

7

Department of Zoology, National Museum of Nature and Science, 4–1–1 Amakubo, Tsukuba, Ibaraki
305–0005, Japan

8The Hokkaido University Museum, Kita 10-jo, Nishi 8-chome, Kita-ku, Sapporo, Hokkaido 060–0810, Japan＊Corresponding author. E-mail: Katsuya.Kimura@me7.sings.jp

Abstract
In November 2013, a single specimen of the platycephalid Rogadiuspristiger (Cuvier in Cuvier and Valenciennes, 1829) was collected from theNanfang-ao Fishing Port, Yilan, Taiwan. Although R. pristiger has been
widely reported from the Indo-West Pacific, it has not been known fromTaiwan. The specimen represents the first record for R. pristiger fromTaiwanese water. Morphological characters for this specimen are reported indetail.
Key words: distribution, range extension, Taiwanese waters, taxonomy,
western North Pacific46

Platax 14: 46-54, 2017

Introduction

specimenOn 2 and 4 November, 2013,

ofplatycephalid

Rogadius

pristiger (Cuvier 1829).

Shao andThe Hokkaido University MuseumChen (1987) reported 17 platycephalid(HoUM), National Museum of Nature

species in 9 genera from Taiwan andand Science, Tsukuba (NSMT) of Japan,

recently Shen and Wu (2011) reported 20and National Museum of Marine Biology

species in 12 genera, but R. pristiger wasand Aquarium (NMMB) of Taiwan

not included in these works. Therefore,

conducted a joint survey of ichthyofauna

this species represents the first record

at the Nanfang-ao

Fi shing Port,

from Taiwanese waters. This report

Yilan, northeastern Taiwan (Fig. 1).

provides a detailed description of thisAmong the specimens we found a singlespecimen.

Fig. 1. Map showing sampling locality.

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Platax 14: 46-54, 2017

Materials and methods

Results

Methods for counts and measurements
follow Hubbs and Lagler (1958), except
for the counts of dorsal-fin spines and thelengths of the first dorsal-fin base that
follow Imamura and Gomon (2010).
Standard and head lengths areabbreviated as SL and HL, respectively.
Vertebrae were counted on a radiograph.
Body scales were examined in detailfrom Scanning Electron Microscope(SEM) images, and numbers of ctenii on
ctenoid scales were counted on thesame images. Institutional abbreviations
follow Fricke and Eschmeyer (2017).

Rogadius pristiger (Cuvier in Cuvier
and Valenciennes, 1829)
Figs. 2–3
Material examined. 1 specimen:
HUMZ 222085, 112 mm SL, Nanfang-ao
Fishing Port, Yilan, Taiwan, 4 Nov. 2013.
Description.
Countsandmeasurements are shown in Table 1.
Body depressed. Body deepest at firstdorsal-fin origin. Head strongly
depressed. Snout long; mouth superior.
Posterior end of upper jaw reaching
beyond anterior margin of eye. Teeth on

Fig. 2. Dorsal (upper) and lateral (lower) views of Rogadius pristiger, HUMZ 222085,
112 mm SL, Nanfang-ao Fishing Port, Yilan, Taiwan.

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Platax 14: 46-54, 2017

upper and lower jaws granular; upper jaw
tooth plate with a small notchanteromedially. Two separated toothplates on vomer; teeth villiform anteriorly,
small and conical posteriorly, becoming
larger posteriorly.
Palatine with two
tooth rows. Nasal with one small spine.
Anterior and posterior nostrils slightly
tubular; former with one flap on its
posteromedial margin. Upper iris lappet
bilobed; lower iris lappet simple. Ocular
flaps absent. Interorbital space narrowand concave. One preocular spine
present, without small spines on its base.
First infraorbital (= lachrymal) finely
serrated ventrally.
Supraorbital ridge
finely serrated. Distinct postocular andpreorbital spines absent. Dorsal surfaceof head with tubercles. Suborbital ridge
finely serrated. Fleshy sensory tubes oncheek region well developed.
Five
spines on preopercle; uppermost spinewith a supplemental spine on its base;lowermost spine antrorse and strong.
Two spines on opercle posteriorly; ridge
for lower spine without serration andtubercles. Cleithral spine short.
Interopercular flap absent. Scales onbody ctenoid dorsally, with ca. 24–33
ctenii posteriorly, cycloid ventrally.
Small ctenoid scales on postorbital area
and opercle. Lateral-line scales with two
external openings. Two dorsal finsnarrowly separated. First dorsal-fin
spine short and isolated. Pectoral fin
slightly concaved posteriorly. Posterior

tip of pelvic fin attaining third anal-fin ray.
Caudal fin truncated.
Color in alcohol. Dorsal side ofbody and head brown, ventral side pale.
First dorsal fin pale basally, with single
black, broad marginal band. Second
dorsal fin pale with many small dark spots.
Anal fin white. Pectoral fin pale withmany small dark spots. Pelvic fin dark,
except for pale base and outer margin.
Caudal fin with white basal band, broad
dusky submarginal band and narrow whiteedge.
Distribution. Widespread in theIndo-West Pacific, including Mozambique,
Madagascar, Red Sea, Gulf of Oman,
Andaman Sea, Indonesia, Gulf ofThailand, Philippines, northwestern
Australia, Papua New Guinea, New
Caledonia, Tonga (Randall, 1995, 2005;
Knapp, 1999; Imamura, 2009; Fricke etal., 2011) and Taiwan (this study).
This specimen isRemarks.
identifiable as a species of the genus
Rogadius Jordan and Richardson, 1908 in
having 54 lateral-line scales, a bilobed
upper iris lappet, no ocular and interopercularflaps, tubercles on the dorsal surface ofthe head, the suborbital ridge finelyserrated, well developed fleshy sensory
tubes on the cheek, and lateral-line scaleswith two external openings (Imamura,1996). Of the 12 valid species of Rogadius,
the present specimen agrees well with R.
pristiger, Rogadius asper (Cuvier in
Cuvier and Valenciennes, 1829) known

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Table 1.

Counts and proportional measurements of examined specimens ofRogadius pristiger.
Present specimen

Syntypes

Non-typesHUMZ 222085

n=5n=8112

94.5 – 119

63.8 – 130

First dorsal-fin rays

I + VIIII + VIIII + VII – VIII (VIII)

Second dorsal-fin rays

111111Anal-fin rays

1111112 + 13 + 8 = 23

2 + 9–12 + 8–9 = 20–23

2 + 9 – 12 + 8 – 9 = 20 – 23(12)Branched caudal-fin rays

6 + 5 = 11

6 + 5 – 6 = 11–12 (12)6 + 5 – 6 = 11–12 (12)Lateral-line scales (LLS)

54

52 – 53

51 – 54

Anterior LLS with a spine

10

6–94 – 10SL (mm)Counts:

Pectoral-fin rays*57

58 – 64

53 – 61

Gill rakers

1+6=71+6–7=7–8

1 + 6–7 = 7–8 (8)Vertebrae

27––

Head length

39.9

37.8 – 38.8

37.1 – 40.3

Predorsal length

37.7

36.9 – 38.3

36.3 – 38.7

Length of first dorsal-fin base

20.1

22.0 – 23.0

20.3 – 24.0

Length of second dorsal-fin base

25.5

24.6 – 26.0

24.4 – 28.3

Length of anal-fin base

28.8

25.3 – 26.3

25.3 – 27.9

Length of caudal peduncle

11.0

10.2 – 11.3

9.7 – 11.2

Depth of caudal peduncle6.8

4.9 – 5.7

5.2 – 5.9

Oblique scale rows**

Proportional measurements (% SL):

Length of first dorsal-fin spine

4.9

5.6 – 6.3 ***5.1 – 7.5

Length of second dorsal-fin spine

16.4

13.6 – 15.0 ****

14.0 – 15.0

Pectoral-fin length

20.8

18.1 – 20.2 ****

17.9 – 20.6

Pelvic-fin length

28.0

26.6 – 29.5 ****

22.1 – 29.3

Caudal-fin length

22.8

19.6 – 21.9 ***19.7 – 22.4

Snout length

29.6

28.6 – 29.7

27.1 – 30.7

Orbital diameter

26.7

28.0 – 30.3

26.1 – 30.5

Upper-jaw length

42.4

37.5 – 39.0

36.8 – 39.7

Lower-jaw length

55.5

57.2 – 59.5

55.3 – 57.1

Interorbital width
5.0
3.4 – 5.1
Mode values indicated in parentheses.
* Upper unbranched + middle branched + lower unbranched rays.
** Slanting downward and forward above lateral line.
*** Based on 3 syntypes.
**** Based on 4 syntypes.

4.0 – 5.8

Proportional measurements (% HL):

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Platax 14: 46-54, 2017from the western Pacific and Rogadius
fehlmanni Knapp, 2012 known fromSomalia, in having a single strong
antrorse preopercular spine (vs. absent or
weak in the others) (e.g., Imamura, 1996,2007, 2009; Knapp, 1999, 2012; Imamura
et al., 2006). It was identified as R.
pristiger by its possession of thefollowing three diagnostic characters forthis species: 57 oblique scale rows
slanting downward and forward above thelateral line (51–61 in R. pristiger vs.
66–76 in R. asper), first dorsal fin with asingle black, broad marginal band (vs.
with 3–5 irregular blackish bands or
randomly arranged blackish spots in R.
asper, and with a submarginal dark band
and a series of small dark spots on spines
in R. fehlmanni), and caudal fin with awhite basal band, a broad dusky
submarginal band and a narrow whiteedge (vs. with 3–5 irregular blackish
bands or a basal blackish band andrandomly arranged blackish spots
posteriorly in R. asper, and with a broadbasal dark blotch followed by a pale areaand 3 or 4 narrow vertical dark bands
posteriorly) (see also Imamura et al.,2006; Knapp, 2012). In addition, thepresent specimen has no remarkabledifferences in counts and proportional
measurements
withsyntypes
andnon-types of R. pristiger (Table 1).
We compared ctenoi d scales
between our 112 mm SL specimen of R.
pristiger with a 118 mm SL specimen of R.

asper (Fig. 3), and found a difference inthe number of ctenii (ca. 24–33 in R.
pristiger vs. ca. 21–23 in R. asper).
Hughes (1981) stated that “the number ofcteni increases with the age of the fish” inthe Platycephalidae and “the number ofcteni is of limited taxonomic value andmust be correlated to scale and specimensize.” The validity of the number ofctenii separating the two species should beevaluated as a taxonomic character in thefuture.
In the Pacific Ocean, this species has
been reported from Indonesia, Gulf ofThailand, the Philippines, Papua New
Guinea,New

Caledonia

andTonga(Randall, 1995, 2005; Knapp, 1999;
Imamura, 2009; Fricke et al., 2011).
Comparative material. Rogadius asper(1 specimen): NSMT-P 119548, 118 mm
SL, Mimase, Kochi, Japan.

Rogadius

pristiger (13 specimens): CAS 52338,63.8 mm SL, MNHN 4529, 101 mm SL,Selebes; CAS 52343, 74.8 mm SL, Luzon
Island; CSIRO CA1860, 130 mm SL,H3306-12, 94.6 mm SL, H3316-01, 125mm

SL,

H3361-06,120mm

SL,Australia; MNHN 4165, syntype, 106 mm
SL, 6855, syntype, 119 mm SL, HUMZ
131413, 123 mm SL, Papua New Guinea;
MNHN 6849, syntype, 94.5 mm SL, 6856,syntype, 108 mm SL, Sulawesi; MNHN
6850, syntype, 116 mm SL, New Caledonia.

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Fig. 3. SEM images of scales on right lateral side of body. A, Rogadius pristiger,HUMZ 222085, 112 mm SL, Taiwan; B, R. asper, NSMT-P 119548, 118mm SL, Japan.

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Platax 14: 46-54, 2017

Hughes, D.R. 1981. Development andorganization of the posterior field ofctenoid scales in the Platycephalidae.
Copeia, 1981: 596-606.
Imamura, H. 1996. Phylogeny of the family
Platycephalidae and related taxa (Pisces:Scorpaeniformes). Species Diversity, 1:123-233.
Imamura, H. 2007. Rogadius mcgroutheri, a
new species of flathead (Teleostei:Platycephalidae) collected from eastern
AustraliaandNew
Caledonia.
Ichthyological Research, 54: 303-307.
Imamura, H. 2009. Platycephalidae. pp. 74-77.
In: Kimura, S., U. Satapoomin and K.
Matsuura (eds). Fishes of Andaman Sea,
west coast of southern Thailand. NationalMuseum of Nature and Science, Tokyo.
Imamura, H. & M.F. Gomon. 2010.
Taxonomic revision of the genus
Ratabulus (Teleostei: Platycephalidae),with descriptions of two new species
from Australia. Memoirs of the Museumof Victoria, 67: 19-33.
Imamura, H., M. Komada & T. Yoshino. 2006.
Recordoftheflatheadfishes(Perciformes: Platycephalidae) collectedfrom Nha Trang, Vietnam. Coastal
Marine Science, 30: 293-300.
Knapp, L.W. 1999. Platycephalidae. pp.
2385-2421. In: Carpenter, K.E. & V.E.
Niem (eds). FAO species identification
guide for fishery purposes. The living
marine resources of the Western Central
Pacific. Volume 4. Bony fishes part 2(Mugilidae to Carangidae). FAO, Rome.
Knapp, L.W. 2012. Rogadius fehlmanni, a newflatheadfish(Scorpaeniformes:Platycephalidae)
fromSomalia.
Proceedings of Biological Society ofWashington, 125: 61-65.
Randall, J.E. 1995. Coastal fishes of Oman.
Crowford House Publishing Pty Ltd,Bathurst. xvi + 439 pp.
Randall, J.E. 2005. Reef and shore fishes ofthe South Pacific. New Caledonia toTahiti and the Pitcairn Islands. Universityof Hawai’i Press., Honolulu. xii + 707 pp.

Acknowledgments
We are especially grateful toMamoru Yabe (Faculty of Fisheries
Sciences, Hokkaido University / HoUM)
for his valuable advice. We also express
our sincere thanks to Martin F. Gomon(Museums Victoria) for his English
corrections and critical comments. This
study is partially conducted under theMoU between HoUM and NMMB signedon 29 July 2014. This study was partly
supported by JSPS (Japan Society for thePromotion of Science) KAKENHI Grant
Number JP 24120001 in Scientific
Research on Innovative Areas “InnovativeMaterials Engineering Based on
Biological Diversity” to the last author(GS) and JSPS KAKENH Grant Number
16K07472 and JSPS Core-to-Core
Program—Research and education
network on Southeast Asian coastal
ecosystems to the fourth author (HI).

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and their distribution in the Southwest
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