Species Diversity 22: 81–85
25 May 2017
DOI: 10.12782/sd.22_81

First Japanese Record of the Barred Perchlet
Plectranthias fourmanoiri (Actinopterygii:
Perciformes: Serranidae) from the Ryukyu Islands
Satokuni Tashiro1,3 and Hiroyuki Motomura2
1 The United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan

E-mail: k0587888@kadai.jp

2 The Kagoshima University Museum, 1-21-30 Korimoto, Kagoshima 890-0065, Japan
3 Corresponding author(Received 26 July 2016; Accepted 17 March 2017)
A single specimen (31.6 mm standard length) of Plectranthias fourmanoiri Randall, 1980, previously known fromChristmas Island (western Indian Ocean) and from the Mariana Islands south to Indonesia and east to the Pitcairn Islands(Pacific Ocean), was collected from Yoron-jima island, Ryukyu Islands, Japan. A full description is given and comparisonsmade. The specimen represents the first record of P. fourmanoiri from Japan and northernmost record of the species.
Key Words: description, distribution, Yoron-jima island, Ryukyu Islands.

Introduction
The anthiine fish genus Plectranthias Bleeker, 1873 is currently known to comprise 52 species from the tropical totemperate Indo-Pacific and Atlantic Oceans, most being ofgenerally small body size and known from only one or two
specimens from relatively deep waters (below scuba-diving
depths from 90–420 m) (Allen and Walsh 2015; Gill et al.
2016). However, some species occur in shallower waters associated with coral or rocky reefs.
During ichthyofaunal surveys of Yoron-jima island,
Ryukyu Islands, Japan (Motomura and Matsuura 2014;
Motomura 2016), a single specimen of Plectranthias wascollected from a rocky reef at a depth of 13 m and subsequently identified as Plectranthias fourmanoiri Randall,
1980, a species previously recorded from Christmas Island(eastern Indian Ocean) and from the Mariana Islands south
to Indonesia and east to the Pitcairn Islands (Pacific Ocean).
Therefore, the Yoron-jima specimen represents the first record of P. fourmanoiri from Japan and northernmost recordof the species.

Materials and Methods
Counts and measurements generally followed Randall(1980). Counts where possible were made on both sides ofthe body. Measurements were made to the nearest 0.1 mm
with needle-point calipers under a dissecting microscope.
Standard length is expressed as SL. Curatorial procedures
followed Motomura and Ishikawa (2013), the specimen examined in present study being deposited in the Kagoshima
University Museum, Japan (KAUM). An underwater pho

tograph of P. fourmanoiri referenced to in present study isregistered at the Image Database of Fishes in the Kanagawa
Prefectural Museum of Natural History, Japan (KPM-NR).
Plectranthias fourmanoiri Randall, 1980
[New Japanese name: Tobiishi-hanadai](Figs 1, 2; Table 1)
Plectranthias fourmanoiri Randall, 1980: 126, fig. 7 (type locality: Enewetak Atoll, Enewetak Island, Marshall Islands;
paratypes localities: Pitcairn Islands; Mangareva, Tuamotu Islands; Tahiti, Society Islands; Tutuila Island, American Samoa; Rarotonga Island, Cook Islands; Christmas
Island); Myers and Shepard 1980: 317 (Guam, Mariana
Islands); Myers 1989: 102, fig. 2 (Guam, Mariana Islands); Kulbicki et al. 1994: 19 (Chesterfield Islands, New
Caledonia); Allen and Adrim 2003: 32 (Banda Islands,
Indonesia); Myers and Donaldson 2003: 616 (Mariana Islands); Randall 2005: 138, unnumbered fig. (Marshall Islands); Fricke et al. 2011: 385 (New Caledonia); Allen andErdmann 2012: 289, unnumbered fig. (Christmas Island;
Molucca Islands, Indonesia).
Material examined. KAUM–I. 70967, 31.6 mm SL, off
Chabana, Yoron-jima island, Ryukyu Islands, Japan, 13 m
depth, hand net, 15 March 2015, coll. by S. Tashiro.
Description. Counts and measurements given in Table
1. Body moderately elongate, laterally compressed; body
depth 3.0 in SL, body width 2.1 in body depth. Head length
2.1 in SL. Dorsal profile of head almost straight. Snoutslightly shorter than orbit diameter. Orbit diameter 4.2 inhead length. Anterior nostril with a short membranous
tube; posterior nostril opening elliptical, located on anterior margin of orbit. Interorbital space very narrow, concave.
© 2017 The Japanese Society of Systematic Zoology

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S. Tashiro and H. Motomura

Fig. 1. Color photographs of Plectranthias fourmanoiri. KAUM–I. 70967, 31.6 mm SL, off Chabana, Yoron-jima island, Ryukyu Islands,
Japan; A fresh, B after preservation.

Mouth large, oblique; maxilla expanded posteriorly, posterior margin slightly beyond level with posterior margin oforbit. Tip of lower jaw protruding anteriorly beyond upper
jaw. Caudal-peduncle depth 3.7 in head length.
Upper jaw with a band of villiform teeth, 6–8 irregularrows anteriorly, decreasing to 2–3 rows posteriorly; paired
stout canine teeth anteriorly on each side of upper jaw; 2stout, inwardly curved teeth near symphysis on either sideof villiform band. Lower jaw with a band of villiform teeth,
4–5 irregular rows anteriorly, decreasing to 2 rows posteriorly; canine teeth absent. Vomer crescent, with 2–3 irregularrows of small teeth. Palatine teeth absent.
Opercle with 3 flat spines; uppermost spine flexible; middle spine largest. Posterior margin of preopercle with three
weakly developed spines, ventral edge without antrorse
spine; subopercle and interopercle without serrae or spines.
Lateral line complete, with tubed scales, weakly archedover pectoral fin, highest below base of 5th dorsal-fin spine,

almost straight over caudal-peduncle region. Body covered
with ctenoid scales; 2 scale rows between lateral line anddorsal-fin origin; 8 scale rows between lateral line and analfin origin; 12 circumpeduncular scale rows; each fin basecovered with small ctenoid scales of ca. half or more small
body scale size; dorsum of head posterior to mid-point ofinterorbital space, preopercle and opercle scaled; 4 obliquescale rows from posteroventral margin of oribit to ventraledge of preopercle, except for single small scale present
close to orbit; no scales on snout, maxilla or ventral surfaceof head. Origin of dorsal fin above 2nd tubed lateral-line
scale; 4th dorsal spine longest; 2nd to 7th dorsal spines eachwith a short fleshy tab; deep notch between spinous andsoft-rayed portions; margin of soft-rayed portion rounded.
Origin of pelvic fin on vertical line between preopercular and opercular margins. Pectoral-fin rays unbranched;base of uppermost pectoral-fin ray below dorsal-fin origin;
8th pectoral ray longest and extending beyond base of pos-

First Japanese record of Plectranthias fourmanoiri83

Fig. 2. Dorsal (A) and lateral (B) views of head of Plectranthias
fourmanoiri. KAUM–I. 70967, 31.6 mm SL; stained with cyanine blue.

teriormost anal-fin ray. Origin of anal fin on vertical line
through 4th ray of dorsal fin; 2nd anal-fin spine longest;
posterior margin of soft-rayed portion truncate and membranes incised. Unbranched caudal-fin rays 13; posterior
margin of caudal fin rounded.
Coloration when fresh (Fig. 1A). Head yellowish-whitewith reddish blotches; pale brown band from anterior partof upper lip to anteroventral margin of orbit; posterior areaof interorbital region brown. Opercle and body with scattered bright yellow and blackish spots. Body reddish dorsally, whitish ventrally; with 5 broad brown bands; 1st bandfrom pre-dorsal region to upper part of opercle; 2nd bandfrom below 3–4th tubed lateral-line scales to below levelof pectoral-fin base; 3rd band from basal part of 4th to last
spinous dorsal fin to abdomen and anal fin base; 4th bandfrom posterior soft portion of dorsal-fin base to posterior
part of anal-fin base; posteriormost band on caudal peduncle. Three distinct black blotches on dorsal body surface, justanterior to dorsal-fin origin, on posterior spinous portion of
dorsal fin, extending onto body (largest), and on posterior
part of dorsal-fin base. Two distinct black blotches ventrally, on abdomen in front of anus and posteriorly on anal-finbase. Spinous part of dorsal fin with red and mottled yellow
blotches; a white membrane distally on 2nd and 3rd spine;
soft-rayed part of dorsal fin mostly pale red, red basally. Pectoral fin pale red, an indistinct dark spot on base. Anal fin
red with mottled yellow blotches basally, spines translucent.
Caudal fin red with 2 yellowish blotches on base.
Coloration of preserved specimen (Fig. 1B). Head whitewith scattered brown spots; posterior area of interorbital

region brown. Body white with 5 broad brown bands and 5
black blotches. All fins transparent.
Distribution. The species is known from Christmas
Island (eastern Indian Ocean), and the following locationsin the Pacific Ocean: Pitcairn Islands, Mangareva (Tuamotu
Islands), Tahiti (Society Islands), Tutuila Island (American Samoa), Rarotonga Island (Cook Islands), Chesterfield
Islands, New Caledonia, Enewetak Atoll (Marshall Islands),
Molucca Islands and Banda Islands (Indonesia), Guam(Mariana Islands) and Yoron-jima island (Ryukyu Islands,
Japan) (Randall 1980; Myers and Shepard 1980; Kulbicki etal. 1994; Allen and Adrim 2003; Fricke et al. 2011; Allen andErdmann 2012; this study).
Remarks. The specimen from Yoron-jima island
agrees well with the original description of Plectranthias
fourmanoiri Randall, 1980; e.g., body depth 3.0 in SL; pectoral-fin length 2.2 in SL; 18 dorsal-fin rays; all pectoral-fin
rays unbranched; lateral line complete, with 25 tubed scales;
3 distinct black blotches dorsally on body, in front of dorsalfin origin, on posterior spinous portion of dorsal fin (largest), extending onto body, and posteriorly on dorsal-finbase; two distinct black blotches ventrally, on abdomen in
front of anus and posteriorly on anal-fin base.
Some morphometric data for the Yoron-jima specimen differed from those given by Randall (1980) for P.
fourmanoiri [1st dorsal-fin spine length (2.8% of SL vs.
3.0–3.6% of SL in the latter); and 3rd anal-fin spine length(15.2% of SL vs. 16.1–16.8% of SL)]. These small differenceswere regarded as intraspecific variations.
Plectranthias fourmanoiri can be separated from all otherspecies of genus Plectranthias, except for P. cirrhitoides Randall, 1980, P. longimanus (Weber, 1913), P. nanus Randall,
1980, and P. winniensis (Tyler, 1966), by the rounded orslightly rounded caudal-fin margin, absence of branchedpectoral-fin rays and maxillary scales or present a single
small cycloid scale at the posterior margin of the maxilla,
and a ventral spot or blotch present from the anal-fin baseto the caudal peduncle (Randall 1980, 2005). The latter four
species, sharing those characters, all occur on coral or rocky
reefs in depths less than 65 m (Randall 2005; Allen andWalsh 2015) and the Yoron-jima specimen was collectedfrom a small crevice on a rocky reef at a depth of 13 m. Plectranthias fourmanoiri is clearly distinguished from the above
four species by having 18 [16–18 (usually 18) in Randall(1980)] dorsal-fin rays (vs. 15 in P. cirrhitoides; 13–15 in P.
longimanus and P. nanus; 15–17 in P. winniensis), a complete
lateral line, with 25 tubed scales (vs. complete, 29–30 in P.
cirrhitoides; incomplete, 10–15 in P. longimanus; incomplete, 15–22 in P. nanus; incomplete, 14–20 in P. winniensis)(Randall 1980, 2005; Heemstra and Randall 2009). Heemstra and Randall (2009) described P. winniensis as having an
incomplete lateral line, with 8–27 tubed scales, and the last
tubed scale below the soft-rayed portion of the dorsal fin.
However, they also described in the key to the western Indian Ocean species that P. winniensis has less than 22 tubed
scales. The counts of tubed scales of P. winniensis given byHeemstra and Randall (2009) as 8–27 is most likely to be
wrong. Plectranthias fourmanoiri is also separated from

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S. Tashiro and H. Motomura

Table 1.

Counts and measurements of Plectranthias fourmanoiri, expressed as percentages of standard length. Means in parentheses.
This study

Standard length (SL; mm)
Counts
Dorsal-fin rays
Anal-fin rays
Pectoral-fin rays
Pelvic-fin rays
Tubed lateral-line scales
Gill rakers (upper+lower)
Measurements (% of SL)
Body depth
Body width
Head length
Snout length
Orbit diameter
Bony interorbital width
Upper-jaw length
Caudal-peduncle depth
Caudal-peduncle lengthPre-dorsal-fin lengthPre-anal-fin length
Pre-pelvic-fin length
Dorsal-fin base length
First dorsal-fin spine length
Longest dorsal-fin spine length
Longest dorsal-fin soft ray length
Anal-fin base length
First anal-fin spine length
Second anal-fin spine length
Third anal-fin spine length
Longest anal-fin soft ray length
Caudal-fin length
Pectoral-fin length
Pelvic-fin spine length
Pelvic-fin length

Randall (1980)

Ryukyu Islands
Non-type
KAUM–I. 70967

Marshall Islands
Holotype
BPBM 17242

Eastern Indian and Pacific oceans
Paratypes
n =12*

31.6

28.9

14.0–37.4

X, 18
III, 7
12
I, 5
25
4+11

X, 18
III, 7
12
I, 5
25
7+12

X, 16–18
III, 7
12–13
I, 5
25
4–7+10–12

33.6
16.1
46.9
9.8
11.1
2.5
21.2
12.7
17.7
43.7
69.7
36.4
49.1
2.8
13.6
15.5
16.1
6.3
18.4
15.2
24.4
25.6
44.6
13.9
25.0

37.1
17.9
45.0
9.2
11.1
2.4
20.8
13.5
18.7
42.6
69.0
38.1
50.9
3.1
14.4
15.5
16.0
6.1
17.9
16.6
24.5
27.7
48.8
14.3
24.9

33.6–37.2 (35.3)
15.4–17.6 (16.8)
45.2–49.2 (46.3)
8.9–9.9 (9.5)
10.8–15.0 (12.0)
2.2–2.9 (2.7)
20.5–22.9 (21.4)
12.0–13.8 (12.8)
18.3–20.7 (19.3)
42.6–44.9 (43.6)
67.5–70.2 (69.0)
36.4–38.5 (37.2)
47.6–50.0 (48.6)
3.0–3.6 (3.3)
13.4–16.4 (14.6)
14.8–16.2 (15.7)
16.1–18.4 (17.2)
6.6–8.0 (7.2)
17.1–19.0 (18.0)
16.1–16.8 (16.4)
23.0–25.7 (24.5)
25.2–27.5 (26.3)
37.0–52.5 (44.0)
13.1–18.5 (15.2)
23.2–29.3 (25.3)*Measurements based on 5 of 14 paratypes.

these species, except for P. cirrhitoides, by having 3 spines[1–4 in Randall (1980)] on the upper part of the preopercular margin (vs. 9–19 in P. longimanus; 4–17 in P. nanus; 6–17
in P. winniensis), and lacking antrorse spine [0–2 (usually
1) in Randall (1980)] on the ventral edge of the preopercle(vs. 2 in the latter 3 species) (Randall 1980; Heemstra andRandall 2009). In addition, P. fourmanoiri differs from P. cirrhitoides by having 13 unbranched caudal-fin rays [13–14(usually 13) in Randall (1980)] (vs. 15 in P. cirrhitoides)(Randall 1980).
Plectranthias fourmanoiri has previously been recorded north of the equator only from Guam, Mariana Islands(Myers and Shepard 1980), and an underwater photographof the species was taken at Ie-jima island, Ryukyu Islands,
Japan (KPM-NR 61080) (Senou 2013). The present specimen from the Ryukyu Islands represents the first specimenbased record of P. fourmanoiri from Japan and the northernmost record for the species.

A new standard Japanese name “Tobiishi-hanadai” isherein proposed for P. fourmanoiri on the basis of the specimen from the Ryukyu Islands. “Tobiishi” meaning steppingstones in Japanese, is derived from the five black blotches on
the body, and “hanadai” is the common Japanese name formembers of the subfamily Anthinae.

Acknowledgments
We are especially grateful to T. Takeshita (Yoron Diving
Service) and K. Nakanishi (Diving Service Aoirokujira) for
their kind assistance while collecting the specimen. We also
appreciate the assistance of Y. Haraguchi (KAUM) and othervolunteers and students of KAUM. This study was supported in part by; Grant-in-Aid for JSPS Fellows (DC2: 289608) to the first author; JSPS KAKENHI Grant Numbers
JP26241027, JP24370041, JP23580259, and JP26450265; theFirst Japanese record of Plectranthias fourmanoiri85

JSPS Core-to-Core Program, “Research and Education Network on Southeast Asian Coastal Ecosystems”; the “Coastal
Area Capability Enhancement in Southeast Asia Project”
of the Research Institute for Humanity and Nature, Kyoto,
Japan; the “Biological Properties of Biodiversity Hotspots inJapan” project of the National Museum of Nature and Science, Tsukuba, Japan; and “Establishment of Research and
Education Network on Biodiversity and Its Conservation in
the Satsunan Islands” project of Kagoshima University adopted by the Ministry of Education, Culture, Sports, Scienceand Technology, Japan.

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