Review of Polydactylus species (Perciformes: Polynemidae)
characterized by a large black anterior lateral line spot,with descriptions of two new species
Hiroyuki Motomura1* and Yukio Iwatsuki2
1

Miyazaki University, the United Graduate School of Agricultural Sciences, Kagoshima University, 1-1 Gakuen-kibanadai-nishi,
Miyazaki 889-2192, Japan (e-mail: a02113u@cc.miyazaki-u.ac.jp)
2
Division of Fisheries Sciences, Faculty of Agriculture, Miyazaki University, 1-1 Gakuen-kibanadai-nishi, Miyazaki 889-2192,
Japan (e-mail: yuk@cc.miyazaki-u.ac.jp)
Received: February 5, 2001 / Revised: April 29, 2001 / Accepted: May 1, 2001

IchthyologicalResearch©The Ichthyological Society of Japan 2001

Ichthyol Res (2001) 48: 337–354

Abstract Nominal Polydactylus species characterized by a large black spot anteriorly on
the lateral line, P. microstomus (Bleeker), P. sextarius mullani (Hora), P. sextarius sextarius(Bloch and Schneider), and P. zophomus Jordan and McGregor, are reviewed. Polydactylus
zophomus, with 5 pectoral filaments, is synonymized under P. microstomus, and P. sextarius
mullani, with 7 pectoral filaments, is elevated to species level (as P. mullani). Polydactylus
microstomus and P. mullani together with P. sextarius (characterized by 6 pectoral filaments) are considered as valid species and redescribed accordingly. Two new species,
P. malagasyensis and P. persicus, each with 6 pectoral filaments, collected from the east coastof Africa, including Madagascar and the Persian Gulf, are also described. Polydactylus
sextarius and the 2 new species are characterized by 6 pectoral filaments. However, P.
sextarius is distinguished from the latter by having lower gill raker counts (mode 28
vs. 31 in the latter) and an atrophied swimbladder (vs. well-developed). Polydactylus
malagasyensis differs from P. persicus in having higher pectoral fin ray counts (14 vs. mode
12 in the latter), the palatines inwardly turned anteriorly (vs. straight), and a longer pectoralfin (mean 24% of standard length vs. 19%).
Key words Polydactylus malagasyensis sp. nov. · Polydactylus microstomus · Polydactylus
mullani · Polydactylus persicus sp. nov. · Polydactylus sextarius

Although the body of Polydactylus species isgenerally tinged with silvery or golden coloration(Motomura and Iwatsuki, 2001), sometimes with several
dark stripes along the longitudinal scale rows aboveand below the lateral line (Motomura et al., 2001a,c),
4 nominal species, P. microstomus (Bleeker, 1851),
P. sextarius mullani (Hora, 1926), P. sextarius sextarius(Bloch and Schneider, 1801), and P. zophomus Jordan
and McGregor in Jordan and Seale, 1907, have a large
black spot anteriorly on the lateral line. These species arefurther characterized by having all the pectoral fin rays
branched except the uppermost 1 or 2 and the vomer
without teeth.
Apart from numerous brief treatments in general classifications and regional faunal studies, Polydactylus
species with a large black lateral line spot have at no time
been reviewed on the basis of type and non-type materials representing wide distributional ranges. Thus, considerable taxonomic confusion has resulted. Accordingly,
the present review of the group has been made on an
Indo-West Pacific basis.

Polydactylus microstomus, originally described from
Bulukumba, Sulawesi, Indonesia, has been recognized
as a valid species characterized by 5 pectoral filaments(Weber and de Beaufort, 1922; Menon and Babu
Rao, 1984). Polydactylus zophomus, originally describedfrom Cavite, Luzon Island, Philippines, has also beenfrequently regarded as a valid species (Jordan andRichardson, 1908; Seale, 1910), although type specimensof the latter have apparently never been compared directly with those of the former. During the present study,
examination of the holotypes of P. zophomus and P. microstomus, and paratype of the former showed that they
represented a single species. Accordingly, P. zophomus isherein regarded as a junior synonym of P. microstomus.
The subspecies, P. sextarius mullani, originally described from Mumbai (⫽ Bombay), India, has often been
misidentified as Polynemus (or Polydactylus) heptadactylus Cuvier in Cuvier and Valenciennes, 1829 (nowrecognized as Filimanus heptadactyla) by subsequent
researchers (Kagwade, 1970; Talwar and Kacker, 1984).
However, the subspecies, characterized by 7 pectoral fila-

338

H. Motomura and Y. Iwatsuki

ments, is herein regarded as valid and raised to full
specific status because it is easily distinguished fromother congeners, including P. sextarius sextarius, by the
number of pectoral filaments and gill rakers and by
swimbladder condition.
Polydactylus sextarius, originally described from
Tranquebar, India, and characterized by 6 pectoral filaments, has been considered to be widely distributed in
the Indo-West Pacific (Menon, 1974; Menon and Babu
Rao, 1984). However, specimens collected from the east
coast of Africa, including Madagascar and the Persian
Gulf, previously identified as P. sextarius, are here
considered to represent 2 undescribed species of
Polydactylus.
This article includes redescriptions of P. microstomus(a senior synonym of P. zophomus), P. mullani, and P.
sextarius, and descriptions of 2 new species, on the basisof a large number of specimens, including types, from awide geographic range in the Indo-West Pacific.

Methods
Counts and measurements generally followed Hubbs
and Lagler (1947) and Feltes (1991), with modifications
following Motomura et al. (2000). Standard length andtotal length are expressed as SL and TL, respectively.
Terminology of the supraneural bones follows Mabee(1988), and the formula for configuration of thesupraneural bones, anterior neural spines, and anterior
dorsal fin pterygiophores follows Ahlstrom et al. (1976).
The configuration of the supraneural bones and vertebral counts were confirmed from radiographs. Institutional codes follow Leviton et al. (1985), with additional
institutional abbreviations as follows: Division ofFisheries Sciences, Miyazaki University, Japan (MUFS);
Phuket Marine Biological Center, Thailand (PMBC);
Shanghai Fisheries University, China (SFU).

2b. Pectoral filaments 6; all first dorsal fin spines
similar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3a. Gill rakers 25–30 (mode 28); second dorsal fin spine
short (mean 6% of SL); swimbladder atrophied(India to New Guinea) . . . . . . . . . . . . . . . P. sextarius
3b. Gill rakers 29–35 (mode 31); second dorsal fin
spine long (mean 7% of SL); swimbladder welldeveloped . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4a. Pectoral fin rays 14; scales below lateral line 10(rarely 9); palatines inwardly turned anteriorly; pectoral fin long (mean 24% of SL); pectoral filaments
short (mean 29% of SL) (east coast of Africa andMadagascar) . . . . . . . . . . . . .P. malagasyensis sp. nov.
4b. Pectoral fin rays 12–14 (mode 12); scales below
lateral line 9 (rarely 8); palatines straight anteriorly; pectoral fin short (mean 19% of SL); pectoral filaments long (mean 32% of SL) (PersianGulf) . . . . . . . . . . . . . . . . . . . . . . . . P. persicus sp. nov.

Polydactylus malagasyensis sp. nov.
(New English name: African blackspot threadfin)(Fig. 1)

Key to the species of Polydactylus
characterized by a large black anterior
lateral line spot

Holotype. AMNH 88029, 125 mm SL, estuary of
Mananjary River (ca. 100 m from sea), Mananjary, eastern
Madagascar (21°05⬘ S, 48°27⬘ E), 30 June 1988, collected by
M.L.J. Stiassny and P.N. Reinthal.
Paratypes. 35 specimens (59–149 mm SL), all from east
coast of Africa and Madagascar. AMNH 231222 (3 specimens),
95–141 mm SL, same data as holotype; AMS I. 28114009 (2),102–104 mm SL, northwest of Madagascar; ANSP 54807, 59 mm
SL, Durban, Natal, South Africa; ANSP 77390, 127 mm SL,
Tugela River, Natal, South Africa; ANSP 86372 (2), 94–136 mm
SL, Delagoa Bay, Mozambique; CAS 66577 (3), 99–117 mm
SL, off Nosy Be, northern Madagascar; CAS 131390 (2),
144–148 mm SL, Natal, South Africa; MUFS 20381, 104 mm
SL, same data as holotype; NRM 10479 (3), 135–149 mm SL,
Majunga, Madagascar; NRM 10480 (4), 74–87 mm SL, Majunga,
Madagascar; USNM 171045, 126 mm SL, Madagascar; USNM
278209, 113 mm SL, Malindi, Kenya; USNM 301505, 125 mm
SL, same data as holotype; USNM 307631, 129 mm SL, Pebane, Mozambique; USNM 358684 (3), 124–139 mm SL,
Mozambique Channel (16°11⬘ S, 43°53⬘ E); USNM 363484 (3),
63–126 mm SL, northwestern coast of Madagascar (13°24⬘ S,
48°42⬘ E); SAM 34057 (3), 121–134 mm SL, off Mozambique(17°56⬘ S, 37°42⬘ E).

1a. Pectoral filaments 5; body and fins tinged withyellowish-silver (India to New Caledonia) . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P. microstomus
1b. Pectoral filaments 6 or 7; body and fins tinged withsilver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2a. Pectoral filaments 7; second spine of first dorsal fin
more robust than other dorsal fin spines (northern
Arabian Sea) . . . . . . . . . . . . . . . . . . . . . . . . P. mullani

Diagnosis. A species of Polydactylus with the following combination of characters: 6 pectoral filaments,
uppermost not reaching to (or extending slightly beyond) posterior tip of pectoral fin; 14 pectoral fin rays;
46–51 (mode 47) pored lateral line scales; 10 (rarely 9, 1
of 21 specimens) scales below lateral line; 29–34 (31) gillrakers; pectoral fin rays long [mean 24% (range 21–26%)
of SL]; pectoral fin base long [12% (10–12%) of SL];

Review of Polydactylus with large spot

339

Fig. 1. Holotype of Polydactylus malagasyensis sp. nov., AMNH 88029, 125 mm SL, estuary of Mananjary River (ca. 100 m fromsea), Mananjary, eastern Madagascar

second dorsal fin spine long [7% (7–9%) of SL]; all pectoral fin rays branched, except uppermost 1 or 2; vomer
without teeth; palatines inwardly turned anteriorly;
swimbladder well-developed; a large black spot anteriorly on lateral line.
Description. Counts and proportional measurements as percentages of SL of the holotype andparatypes of Polydactylus malagasyensis sp. nov. aregiven in Table 1. Characters given in the diagnosis are notrepeated here. Data for the holotype are presented first,
followed by paratype data (if different) in parentheses.
Body oblong, compressed; maxilla covered with scales;
posterior margin of preopercle serrated; lower lip welldeveloped; posterior margin of maxilla extending slightly
beyond (same, or reaching) level of posterior margin of
adipose eyelid; depth of posterior portion of maxilla lessthan dermal eye opening; teeth villiform, in broad bands
on palatines and ectopterygoids; thickness of base of
second spine of first dorsal fin slightly more robust thanother first dorsal fin spines (same, or all first dorsal fin
spines similar); lateral line simple, extending from upper
end of gill opening to upper end of lower caudal fin lobe;
formula for configuration of supraneural bones, anterior
neural spines and anterior dorsal pterygiophores 0/0/0⫹ 2/1 ⫹ 1/1/1/1/1/; vertebrae 10 ⫹ 14.
Color of preserved specimens.—Head and body brown
dorsally, pale yellow ventrally; posterior margins of firstand second dorsal fins grayish-black, other parts paleyellow; pelvic fin and pectoral filaments pale yellow; density of pectoral fin pigmentation highly variable; base ofanal fin surrounded by scattered melanophores; a large
black spot anteriorly on lateral line.
Distribution and habitat. Polydactylus malagasyensis
is currently known only from Kenya, Mozambique,South Africa, and Madagascar (Fig. 2). The species islikely to be distributed over a wider area, including
Tanzania and Somalia, east coast of Africa. The collection data available for the species indicated that specimens had been collected from both estuaries (less than
5.5 m) and offshore (16–62 m).
Etymology. The name “malagasyensis” is based on
Malagasy, the old name for Madagascar, in reference tothe holotype locality.
Remarks. Polydactylus malagasyensis sp. nov., previously identified as P. sextarius (Smith, 1986; Menonand Babu Rao, 1984), is herein regarded as representing
a new species on the basis of its unique combination ofmorphological characteristics (see Discussion).

Polydactylus microstomus (Bleeker, 1851)(English name: small-mouthed threadfin)(Fig. 3)Polynemus microstoma Bleeker, 1851: 217 (type locality:
Bulukumba, Sulawesi, Indonesia).
Polydactylus zophomus Jordan and McGregor in Jordan and
Seale, 1907: 11, Fig. 4 (type locality: Cavite, Luzon Island,
Philippines).
Holotype. RMNH 6044, 53 mm SL, Bulukumba, Sulawesi,
Indonesia.
Other material. 50 specimens (51–158 mm SL), all fromeastern Indian and western Pacific Oceans. AMS I. 10471,
158 mm SL, Manila, Luzon Island, Philippines; CAS 120111(formerly SU 20111, non-type specimen of P. zophomus Jordan
and McGregor, 1907), 140 mm SL, Cavite Province, Manila Bay,
Luzon Island, Philippines; CAS 120113 (formerly SU 20113,
holotype of P. zophomus Jordan and McGregor, 1907), 138 mm
SL, Cavite Province, Manila Bay, Luzon Island, Philippines;

340

H. Motomura and Y. Iwatsuki

Fig. 2. Distributional records for Polydactylus species with a large anterior lateral line spot

CAS 127663 (2 specimens), 80–83 mm SL, Cotabato, Mindanao
Island, Philippines; FMNH 40769, 121 mm SL, Iloilo, Panay
Island, Philippines; FMNH 47393, 80 mm SL, Manila Bay,
Luzon Island, Philippines; FMNH 47411 (2), 79–80 mm SL,
Iloilo, Panay Island, Philippines; FMNH 90792 (2), 96–102 mm
SL, 12.8 km offshore of Mandapam, Tamil Nadu, India; FMNH
91310, 84 mm SL, 12.8 km offshore of Mandapam, Tamil Nadu,
India; FRLM 15773, 91 mm SL, Kuta, Lombok Island, Indonesia; FRLM 23518, 116 mm SL, Passo, Baguala Bay, Ambon,
Indonesia; FRLM 23520, 101 mm SL, Passo, Baguala Bay,
Ambon, Indonesia; FSKU 20101, 96 mm SL, Nuguria Island,
Papua New Guinea; MUFS 14159, 154 mm SL, mouth of
Ouenghi River, New Caledonia; MUFS 18543, 78 mm SL,
Makassar (⫽Ujung Pandang), Indonesia; NTM S. 14607-009,
140 mm SL, Pasar Oeba, Kupang, Timor, Indonesia; PMBC
uncatalogued, 81 mm SL, Bangrong, eastern Phuket Island,
Thailand; RMNH 33552 (8), 76–132 mm SL, Bali, Sumbawa,
Sulawesi, Ambon and Seram, Indonesia and New Guinea;
USNM 55598 (2 specimens including a paratype of P.
zophomus Jordan and McGregor, 1907), 137–151 mm SL,
Cavite Province, Manila Bay, Luzon Island, Philippines; USNM
113209, 148 mm SL, Manila, Luzon Island, Philippines; USNM
113210 (4), 78–148 mm SL, mouth of Santiago River, Pagapas
Bay, Luzon Island, Philippines; USNM 113211, 51 mm SL,
Sandakan Bay, Sabah, Malaysia, Kalimantan; USNM 278196,
148 mm SL, Kampung Loleba, Halmahera Island, Indonesia;
USNM 278211 (10), 115–131 mm SL, Talemaninar, Gulf ofMannar, Sri Lanka; USNM 300898, 132 mm SL, off Myanmar,
northern Bay of Bengal (19°32⬘ N, 92°52⬘ E); ZMH 13649,
128 mm SL, New Guinea; ZMH 13650, 88 mm SL, Manila Bay,
Luzon Island, Philippines.

Diagnosis. A species of Polydactylus with the following combination of characters: 5 (rarely asymmetrically

5 and 6, 1 of 51 specimens) pectoral filaments, uppermost
not reaching to (or extending slightly beyond) posterior
tip of pectoral fin; 13 or 14 (mode 13; rarely 12 or 15, 2 of
51 specimens) pectoral fin rays; 46–49 (47) pored lateralline scales; 9 or 10 (10; rarely 8, 1 of 36 specimens) scales
below lateral line; 24–33 (29) gill rakers; pectoral fin rays
short [mean 18% (range 17–20%) of SL]; all pectoral fin
rays branched, except uppermost 1 or 2; vomer without
teeth; swimbladder well-developed; a large black spot
anteriorly on lateral line.
Description. Counts and proportional measurements
as percentages of SL of the holotype and other specimens
of Polydactylus microstomus are given in Table 2. Characters given in the diagnosis are not repeated here. Data forthe holotype are presented first, followed by other specimen data (if different) in parentheses.
Body oblong, compressed; maxilla covered with scales;
posterior margin of preopercle serrated; lower lip welldeveloped; posterior margin of maxilla reaching to(same, or slightly short of) level of posterior margin of
adipose eyelid; depth of posterior portion of maxilla lessthan dermal eye opening; teeth villiform, in broad bands
on palatines and ectopterygoids; palatines inwardly
turned anteriorly; thickness of base of all first dorsal
fin spines similar (same, or second spine of first dorsal fin
slightly more robust than others); lateral line simple,
extending from upper end of gill opening to upper endof lower caudal fin lobe; [formula for configuration of
supraneural bones, anterior neural spines, and anterior

Review of Polydactylus with large spot

341

Table 1. Counts and measurements of the holotype and paratypes of Polydactylus malagasyensis sp. nov., expressed as percentages of standard length

Standard length (mm)Counts
Dorsal fin rays
Anal fin rays
Pectoral fin rays
Pectoral filaments
Pelvic fin rays
Pored lateral line scales
Scales above/below lateral line
Gill rakers
Measurements
Head length
Body depth
Second body depth
Body width at pectoral fin base
Snout length
Dermal eye opening
Orbit diameter
Interorbital width
Postorbital length
Upper jaw lengthPre-1st dorsal fin lengthPre-2nd dorsal fin length
Preanal fin length
First dorsal fin origin to anal fin origin
Pelvic fin origin to anal fin origin
Second dorsal fin base length
Anal fin base length
Longest pectoral fin length
Longest pectoral filament length (6th)Pectoral fin base length
Longest pelvic fin ray length (1st)Longest 1st dorsal fin spine length (3rd)Second dorsal fin spine length
Longest 2nd dorsal fin ray length (2nd)Longest anal fin spine length (3rd)Longest anal fin ray length (2nd)Caudal peduncle length
Caudal peduncle depth
Upper caudal fin lobe length
Lower caudal fin lobe length

Holotype of
Polydactylus malagasyensis
AMNH 88029

Paratypes of
Polydactylus malagasyensis(n ⫽ 35)

125

59–149

VIII-I, 13
III, 12
14
6
I, 5
47
6/10
13 ⫹ 18 ⫽ 31

VIII-I, 12–13 (usually 13)
III, 12
14
6
I, 5
46–51
5–6/9–10
12–16 ⫹ 17–19 ⫽ 29–34

34
35
35
16
6
8
9
8
19
14
40
64
65
48
26
17
18
26
28
12
17
24
7
22
8
21
21
15
39
38

31–35 (33)
31–35 (34)
32–36 (34)
11–17 (14)
5–7 (6)
7–9 (8)
8–11 (9)7–10 (8)18–20 (19)
13–14 (13)36–41 (39)61–65 (64)
63–68 (66)45–48 (46)
25–31 (27)
16–19 (17)
16–19 (18)
21–26 (24)
27–31 (29)
10–12 (12)14–19 (17)22–25 (23)
7–9 (8)
20–24 (21)
7–11 (9)18–22 (19)
19–23 (21)
14–16 (15)35–40 (39)
34–38 (36)Means in parentheses include holotype data

dorsal pterygiophores usually 0/0/0 ⫹ 2/1 ⫹ 1/1/1/1/1/,
rarely 0/0/0 ⫹ 2/1 ⫹ 1/1/1 ⫹ 1/1/1/ (1 of 46 specimens
confirmed, probably a malformation)]; (vertebrae
10 ⫹ 14).
Color in fresh.—Based on color transparencies of
FRLM 15773, 23518, 23520, and MUFS 14159 (4 specimens, 91–154 mm SL): head and upper sides of trunk
tinged yellowish-silver, becoming lighter silver on lower
sides; snout semitranslucent; posterior margins of firstand second dorsal fins and caudal fin slightly blackish,remaining parts translucent yellowish-white; pectoral finmembrane yellowish; pectoral filaments faintly white;anterior margins and origins of pelvic and anal fins
faintly white, remaining parts yellow; a large black spot
anteriorly on lateral line.
Color of preserved specimens.—Head and body brown
dorsally, pale yellow ventrally; posterior margins of firstdorsal fin grayish-black, other parts with scatteredmelanophores; posteriormost portions of second dorsal,
anal, and caudal fins blackish, other parts translucent;342

H. Motomura and Y. Iwatsuki

Fig. 3. Polydactylus microstomus (Bleeker, 1851). A Holotype of Polynemus microstomus Bleeker, 1851, RMNH 6044, 53 mm SL,
Bulukumba, Sulawesi, Indonesia. B Polydactylus microstomus, MUFS 14159, 154 mm SL, mouth of Ouenghi River, New
Caledonia

pelvic fin and pectoral filaments pale yellow; density ofpigmentation of pectoral fin highly variable; a large black
spot anteriorly on lateral line.
Distribution and habitat. Polydactylus microstomus
is currently known from the Indian Ocean, where it
ranges from Tamil Nadu, east of the southernmost tip ofIndia, Sri Lanka, Myanmar, and Phuket Island, Thailand,
to the West Pacific where it ranges from Taiwan (Shen,
1984, 1993) to New Caledonia, being relatively common
in the eastern part of Indonesia and Philippines (see Fig.
2). However, examples of P. microstomus have at no time
(apparently) been collected from Australian waters.
The species inhabits turbid coastal waters, estuaries,
and mangrove creeks as well as mangrove-lined rivers.
Most of the collection data available indicated the specimens were taken from depths of less than 2 m. However,

Schroeder (1980) reported the species in depths of lessthan 20 m in the Philippines. Furthermore, a specimen(USNM 300898, 132 mm SL) from Myanmar was purportedly collected from a depth of 55 m.
Remarks. Bleeker (1851) described Polynemus
microstoma on the basis of a single specimen, 74 mm TL,
but subsequently (Bleeker, 1878) referred to 13 specimens (74–190 mm TL) in his Trichidion microstoma(group A, 10 specimens; group B, 1 specimen; group C,
1 specimen; group D, 1 specimen) (Hubrecht, 1879).
Nine Bleeker specimens are presently held at RMNH,
all registered as RMNH 6044; 53 mm SL (caudal fin
broken but ca. 73 mm TL), 76 mm SL (100 mm TL),
77 mm SL (100 mm TL), 79 mm SL (101 mm TL), 81 mm
SL (107 mm TL), 89 mm SL (122 mm TL), 91 mm SL(125 mm TL), 106 mm SL (143 mm TL), and 132 mm

Review of Polydactylus with large spot

343

Table 2. Counts and measurements of the holotype of Polynemus microstomus, holotype, paratype, and non-type specimen of
Polydactylus zophomus, and non-type specimens of Polydactylus microstomus, expressed as percentages of standard length
Holotype of
Polynemus
microstomus
RMNH 6044

Holotype of
Polydactylus
zophomusCAS 120113

Paratype and non-type
specimen of
Polydactylus zophomus
USNM 55598(n ⫽ 2)

Non-type
specimens of
Polydactylus
microstomus(n ⫽ 47)

Standard length (mm)

53

138

137–151

51–158Counts
Dorsal fin rays

VIII-I, 13

VIII-I, 13

VIII-I, 12–13

III, 12

III, 12

III, 12

14
5
I, 5
—
—/—
12 ⫹ 16 ⫽ 28

14
5
I, 5
47
—/—
13 ⫹ 16 ⫽ 29

13–14
5
I, 5
48–49
—/9
12–13 ⫹ 16–18 ⫽ 28–31

VIII-I, 12–14(usually 13)
III, 11–12(usually 12)
12–15
5
I, 5
46–49
6–7/8–10
10–14 ⫹ 13–18 ⫽ 24–33

31
27
28
8
—
—
—
—
18
—
35
61
64
40
29
16
15
—
—
10
—
21
—
17
10
16
25
11
—
—

34
30
32
17
6
8
10
9
19
13
39
64
68
46
29
18
17
20
27
11
19
25
7
22
8
20
20
13
33
—

33–34
29–32
30–32
15–17
6
8–9
9
9
19–20
13–14
37–39
62–63
67–68
45–46
29
15–17
17
19–20
26–28
11
19
23–24
8
21–22
8
18–19
20–21
13–14
36–37
29–36

29–36 (33)
26–36 (32)
30–37 (34)
11–15 (13)
5–7 (6)
7–10 (8)
8–11 (10)
8–10 (9)17–22 (19)
12–14 (13)35–41 (39)59–67 (64)
62–71 (68)
45–51 (47)
25–32 (30)
15–18 (17)
14–19 (17)17–20 (18)
21–30 (26)
10–12 (11)
16–20 (18)
21–26 (24)
6–10 (8)17–24 (21)
7–11 (9)16–21 (19)
18–22 (21)
13–15 (14)31–41 (36)
31–39 (35)Anal fin rays
Pectoral fin rays
Pectoral filaments
Pelvic fin rays
Pored lateral line scales
Scales above/below lateral line
Gill rakers
Measurements
Head length
Body depth
Second body depth
Body width at pectoral fin base
Snout length
Dermal eye opening
Orbit diameter
Interorbital width
Postorbital length
Upper jaw lengthPre-1st dorsal fin lengthPre-2nd dorsal fin length
Preanal fin length
First dorsal fin origin to anal fin origin
Pelvic fin origin to anal fin origin
Second dorsal fin base length
Anal fin base length
Longest pectoral fin length
Longest pectoral filament length (5th)Pectoral fin base length
Longest pelvic fin ray length (1st)Longest 1st dorsal fin spine length (3rd)Second dorsal fin spine length
Longest 2nd dorsal fin ray length (2nd)Longest anal fin spine length (3rd)Longest anal fin ray length (2nd)Caudal peduncle length
Caudal peduncle depth
Upper caudal fin lobe length
Lower caudal fin lobe length

Means in parentheses include data from type specimens

SL (178 mm TL). Although the caudal fin was broken in
the smallest specimen, the total length of the latter
was estimated from the measurements of 30 undamaged
specimens (76–154 mm SL) of Polydactylus microstomus
examined during this study, the total length being 1.37
times as long as standard length. The estimated total

length (ca. 73 mm TL) of the smallest specimen of
RMNH 6044 is closest to that (74 mm TL) given by
Bleeker. Accordingly, we recognized this specimen as theholotype of Polynemus microstoma, the remaining 8
being reregistered (RMNH 33552) as nontype Bleeker
specimens.

344

Polydactylus zophomus was described as a new
species, on the basis of 2 specimens, by Jordan and
McGregor (in Jordan and Seale, 1907). Although theauthors referred to 4 examples of the species, they clearly
indicated a “Type” (⫽holotype) and “Co-type” (single
specimen only), being registered as USNM 55598 and SU
20113, respectively. The 2 remaining specimens, therefore, cannot be considered as having any type status.
Notwithstanding, Böhlke (1953) listed a holotype and2 paratypes, being registered as USNM 55598 (1 specimen), SU 20111 (1 specimen), and SU 20113 (1 specimen), respectively, in the type catalogue of the Natural
History Museum, Stanford. However, in actual fact
USNM 55598 and CAS 12011 (formerly SU 20111) each
included 2 specimens. Examination of these specimens
during the present study showed 3 of them to be P.
zophomus, whereas the fourth (included in CAS 120111)
was a sciaenid fish, Dendrophysa russelli (Cuvier, 1830),
characterized by a single tapering mental barbel on thelower jaw, uniform teeth on the lower jaw, and a strong
second anal fin spine (14.3% of SL) (Trewavas, 1977; K.
Sasaki, personal communication). The sciaenid specimen
has been reregistered as CAS-SU 69833 and is considered as having no type status and no relevance to thedescription of P. zophomus.
Of the remaining specimens, therefore, CAS 120113(1 specimen) is the only unequivocal type specimen of
P. zophomus, being the most likely holotype. Although
the figure of the “Type” in the original description did
not indicate the size of the specimen, CAS 120113 wasfound to have a label with the inscription “drawn,” attached to the abdomen on the right side. Therefore, we
believe that this specimen is the true holotype of thespecies, despite the (presumably erroneous) reference to
USNM 55598 as “Type” in the original description.
Regarding the remaining specimens, CAS 120111
clearly has no type status, there being no labels or registration evidence suggesting otherwise. On the other
hand, the 2 specimens included in USNM 55598 constitute a single paratype and another non-type specimen. In
the absence of any documented evidence enabling
identification of the paratype, which of the two specimens is in fact the latter must for the meantime remainunresolved.
The holotype, paratype, and 2 non-type specimens of
P. zophomus were all found to be conspecific, being
the same species as the specimens considered here as P.
microstomus. Their meristic and morphological characters are included in Table 2.
Günther (1860) described 2 specimens with 5 pectoral
filaments and a black blotch on the lateral line nearits origin as Polynemus plebejus, but the specimens wereclearly Polydactylus microstomus. Incidentally, the spe-

H. Motomura and Y. Iwatsuki

cies name, microstoma, given by Bleeker (1851), ischanged to microstomus in accordance with the masculine gender of the genus name.

Polydactylus mullani (Hora, 1926)(New English name: Arabian blackspot threadfin)(Fig. 4)Polynemus sextarius mullani Hora, 1926: 453 (type locality:
Mumbai [⫽Bombay], India).
Holotype. ZSI-F 10747, 157 mm SL, Mumbai, Maharashtra,
India.
Paratypes. 3 specimens (92–106 mm SL). ZSI-F 1074810750 (3 specimens), 92–106 mm SL, same data as holotype.
Other material. 41 specimens (42–188 mm SL), all from thenorthern Arabian Sea. ANSP 77129 (2), 52–82 mm SL, off
Mumbai, Maharashtra, India; ANSP 77527 (4), 49–94 mm SL,
off Mumbai, Maharashtra, India; ANSP 105539, 151 mm SL,
Mumbai, Maharashtra, India; MUFS 19110-19113, 19127,
19534, 19550 (7), 116–188 mm SL, Mumbai, Maharashtra, India;
USNM 278229 (2), 105–125 mm SL, off Gavater, Pakistan(24°54⬘ N, 61°54⬘ E); USNM 357760 (3), 42–172 mm SL, off Gulf
of Kutch, Gujarat, India (22°45⬘ N, 68°24⬘ E); USNM 358687 (2of 22), 132–175 mm SL, off Kathiawar Peninsula, Gujarat, India(20°10⬘ N, 65°50⬘ E); USNM 358688 (16), 123–148 mm SL,
Pakistan (24°54⬘ N, 63°52⬘ E); USNM 358690 (4), 42–117 mm
SL, off Kathiawar Peninsula, Gujarat, India.

Diagnosis. A species of Polydactylus with the following combination of characters: 7 (rarely asymmetrically 6
and 7, 1 of 45 specimens) pectoral filaments, uppermost
extending well beyond posterior tip of pectoral fin; 13 or
14 (mode 13) pectoral fin rays; 46–50 (48) pored lateralline scales; 9 or 10 (10) scales below lateral line; 31–35(32) gill rakers; pectoral fin rays moderate [mean 20%(range 19–22%) of SL]; all pectoral fin rays branched,
except uppermost 1 or 2; vomer without teeth; swimbladder well-developed; a large black spot anteriorly onlateral line.
Description. Counts and proportional measurements as percentages of SL of the holotype, paratypes,
and other specimens of Polydactylus mullani are given in
Table 3. Characters given in the diagnosis are not repeated here. Data for the holotype are presented first,
followed by paratype and other specimen data (if different) in parentheses.
Body oblong, compressed; maxilla covered with scales;
posterior margin of preopercle serrated; lower lip welldeveloped; posterior margin of maxilla reaching to (justreaching in adults; extending well beyond in young) levelof posterior margin of adipose eyelid; depth of posterior
portion of maxilla less than dermal eye opening; teeth
villiform, in broad bands on palatines and ectopterygoids; palatines inwardly turned anteriorly; thickness ofbase of second spine of first dorsal fin more robust than

Review of Polydactylus with large spot

345

Fig. 4. Polydactylus mullani (Hora, 1926). A Holotype of Polynemus sextarius mullani Hora, 1926, ZSI-F 10747, 157 mm SL,
Mumbay, India. B Polydactylus mullani, MUFS 19127, 169 mm SL, Mumbai, India

other first dorsal fin spines; lateral line simple, extending
from upper end of gill opening to upper end of lower
caudal fin lobe; (formula for configuration of supraneuralbones, anterior neural spines, and anterior dorsal
pterygiophores usually 0/0/0 ⫹ 2/1 ⫹ 1/1/1/1/1/); (vertebrae 10 ⫹ 14).
Color in fresh.—Based on color transparencies of
MUFS 19110-19113 (4 specimens, 130–167 mm SL): headand upper sides of trunk tinged darkly silver, becoming
lighter silver on lower sides; snout semitranslucent; anterior and posterior margins of first and second dorsal, anal,and caudal fins slightly blackish, other parts gray; pectoral
fin membrane gray with scattered melanophores; base ofpectoral filaments white, becoming dark posteriorly; anterior margin and lower tip of pelvic fin gray, other parts
white; a large black spot anteriorly on lateral line.
Color of preserved specimens.—Head and body brown
dorsally, silver ventrally; anterior and posterior margins

of first and second dorsal, anal, and caudal fins black,other parts yellowish-white; pectoral fin membrane pale
white with scattered melanophores; base of pectoral filaments white, becoming dark posteriorly; lower tip ofpelvic fin black, other parts white; a large black spot
anteriorly on lateral line.
Distribution and habitat. Polydactylus mullani is currently known only from the northern Arabian Sea (seeFig. 2), the species being relatively common in that area.
The collection data available indicated the specimens as
having been taken from depths of 14–115 m.
Remarks. Polynemus sextarius mullani was originallydescribed as a new subspecies by Hora (1926) on the basisof 4 specimens (holotype and 3 paratypes) (Menon andYazdani, 1968). Although the 3 paratypes each have apreliminary label, 167, 197, and 210, respectively, attachedto the body, 3 collection registration labels (ZSI-F 1074810750) had simply been assigned to the lot as a whole,

346

H. Motomura and Y. Iwatsuki

Table 3. Counts and measurements of the holotype and paratypes of Polynemus sextarius mullani and non-type specimens of
Polydactylus mullani, expressed as percentages of standard length

Standard length (mm)Counts
Dorsal fin rays
Anal fin rays
Pectoral fin rays
Pectoral filaments
Pelvic fin rays
Pored lateral line scales
Scales above/below lateral line
Gill rakers
Measurements
Head length
Body depth
Second body depth
Body width at pectoral fin base
Snout length
Dermal eye opening
Orbit diameter
Interorbital width
Postorbital length
Upper jaw lengthPre-1st dorsal fin lengthPre-2nd dorsal fin length
Preanal fin length
First dorsal fin origin to anal fin origin
Pelvic fin origin to anal fin origin
Second dorsal fin base length
Anal fin base length
Longest pectoral fin length
Longest pectoral filament length (7th)Pectoral fin base length
Longest pelvic fin ray length (1st)Longest 1st dorsal fin spine length (3rd)Second dorsal fin spine length
Longest 2nd dorsal fin ray length (2nd)Longest anal fin spine length (3rd)Longest anal fin ray length (2nd)Caudal peduncle length
Caudal peduncle depth
Upper caudal fin lobe length
Lower caudal fin lobe length

Holotype of
Polynemus sextarius
mullani
ZSI-F 10747

Paratypes of
Polynemus sextarius
mullani
ZSI-F 10748-10750(n ⫽ 3)

Non-type specimens of
Polydactylus mullani(n ⫽ 41)157

92–10642–188

VIII-I, 13
III, 12
14
7
I, 5
49
6/10
16 ⫹ 19 ⫽ 35

VIII-I, 12–13
III, 11–12
14
6–7
I, 5
47–48
6/9–10
14–15 ⫹ 18–20 ⫽ 33–34

VIII-I, 12–13 (usually 13)
III, 11–12 (usually 12)
13–14
7
I, 5
46–50
5–7/9–10
13–16 ⫹ 18–21 ⫽ 31–35

34
33
32
13
6
6
9
9
21
16
40
63
70
48
32
17
16
21
36
11
18
—
—
20
9
19
20
13
—
—

33–34
31–34
30–34
14–15
6
8
9
9–10
17–20
14–15
36–40
61–64
64–67
43–48
27–29
17–19
16
19–21
26–32
10–11
16–18
20–25
8–9
17–23
8–9
17–21
21–22
13–14
32–40
39

33–37 (35)
28–35 (33)
26–35 (32)
12–17 (14)
4–7 (5)
5–9 (8)
9–11 (10)
8–10 (9)19–22 (21)
14–17 (15)37–41 (39)
61–67 (64)
65–72 (68)
38–50 (46)
26–32 (29)
15–18 (17)
14–17 (16)
19–22 (20)28–45 (33)
11–12 (11)
16–20 (18)
21–27 (23)
7–12 (8)19–25 (22)
7–13 (9)18–24 (20)
18–25 (21)
10–14 (13)32–52 (39)
32–50 (38)Means in parentheses include data from type specimens

without allocation to individual specimens. Accordingly,
we arbitrarily refer the registration numbers ZSI-F 10748,-10749, and -10750 to specimens 167 (106 mm SL), 197(97 mm SL), and 210 (92 mm SL), respectively.
Polydactylus sextarius mullani is herein raised to
specific status (as P. mullani), because the species canbe easily distinguished from other congeners, including
P. sextarius sextarius. Polydactylus mullani has been fre-quently misidentified as Filimanus heptadactyla (Cuvier
in Cuvier and Valenciennes, 1829) (Kagwade, 1970, as
Polynemus heptadactylus; Talwar and Kacker, 1984, as
Polydactylus heptadactylus). However, P. mullani differsfrom the latter in having wider teeth bands on the upperand lower jaws (compared with the space separating theteeth bands on opposing premaxilla vs. narrower teeth
bands on the upper and lower jaws in the latter), theReview of Polydactylus with large spot

347

Fig. 5. Holotype of Polydactylus persicus sp. nov., MCZ 60001, 121 mm SL, Kuwait Bay, Kuwait, Persian Gulfbasisphenoid in contact with the prootic (vs. not in contact), lower gill raker counts (31–35 vs. 35–41), and alarge black spot present anteriorly on the lateral line (vs.
absent; Feltes, 1991; this study, see Comparative material
examined). Furthermore, whereas P. mullani is currently
known only from the northern Arabian Sea in the Indian
Ocean, F. heptadactyla is distributed in the western
Pacific Ocean (Feltes, 1991; this study).
The body appearance of P. mullani varies remarkably
with overall fish growth, compared with that of the other4 species with a large black anterior lateral line spot. The
uppermost pectoral filament and posterior margin of themaxilla in young specimens (less than ca. 60 mm SL) of P.
mullani reach (vs. not reaching in adults) the anal
fin origin and extend well beyond (vs. just reaching or
not reaching) the posterior margin of the adipose eyelid,
respectively. Furthermore, the upper and lower caudal
fin lobes of young specimens (less than ca. 60 mm SL) of
P. mullani are extremely long [mean 51% (range 50–52%) of SL and 47% (43–50%) of SL, respectively vs.
38% (32–42%) of SL and 36% (32–39%) of SL, respectively, in adults]. These growth-related features are notfound in the other 4 species.

Polydactylus persicus sp. nov.
(New English name: Persian blackspot threadfin)(Fig. 5)
Holotype. MCZ 60001, 121 mm SL, Kuwait Bay, Kuwait,
Persian Gulf (29°30⬘ N, 47°50⬘ E), July 1982, collected by
R.G. Arndt.

Paratypes. 12 specimens (48–124 mm SL), all from thePersian Gulf. AMS I. 40432-001, 103 mm SL, same data as
holotype; BMNH 2000.9.25.1, 93 mm SL, same data as holotype;
KU 10528, 112 mm SL, Al Faw, Iraq; MCZ 59251 (5 specimens,
including 1, 63 mm SL, cleared and stained), 48–80 mm SL,
mouth of Qasr River, Kuwait Bay, Kuwait, Persian Gulf (29°30⬘
N, 48°15⬘ E); MCZ 158350 (2), 92–121 mm SL, same data as
holotype; MUFS 20410, 124 mm SL, same data as MCZ 59251;
USNM 363075, 96 mm SL, same data as holotype.

Diagnosis. A species of Polydactylus with the following combination of characters: 6 pectoral filaments, uppermost extending well beyond posterior tip of pectoral
fin; 12 or 13 (mode 12; rarely 14, 1 of 12 specimens)
pectoral fin rays; 46–49 (48) pored lateral line scales; 9(rarely 8, 1 of 12 specimens) scales below lateral line;
29–35 (31) gill rakers; pectoral fin rays short [mean19% (range 18–20%) of SL]; pectoral fin base short[10% (10–11%) of SL]; second dorsal fin spine long
[7% (6–9%) of SL]; all pectoral fin rays branched, except
uppermost 1 or 2; vomer without teeth; palatines straightanteriorly; swimbladder well-developed; a large black
spot anteriorly on lateral line.
Description. Counts and proportional measurements as percentages of SL of the holotype andparatypes of Polydactylus persicus sp. nov. are given in
Table 4. Characters given in the diagnosis are not repeated here.
Body oblong, compressed; maxilla covered with scales;
posterior margin of preopercle serrated; lower lip welldeveloped; posterior margin of maxilla not reaching tolevel of posterior margin of adipose eyelid; depth ofposterior portion of maxilla less than dermal eye opening; teeth villiform, in broad bands on palatines and348

H. Motomura and Y. Iwatsuki

Table 4. Counts and measurements of the holotype and paratypes of Polydactylus persicus sp. nov., expressed as percentages ofstandard length

Standard length (mm)Counts
Dorsal fin rays
Anal fin rays
Pectoral fin rays
Pectoral filaments
Pelvic fin rays
Pored lateral line scales
Scales above/below lateral line
Gill rakers
Measurements
Head length
Body depth
Second body depth
Body width at pectoral fin base
Snout length
Dermal eye opening
Orbit diameter
Interorbital width
Postorbital length
Upper jaw lengthPre-1st dorsal fin lengthPre-2nd dorsal fin length
Preanal fin length
First dorsal fin origin to anal fin origin
Pelvic fin origin to anal fin origin
Second dorsal fin base length
Anal fin base length
Longest pectoral fin length
Longest pectoral filament length (6th)Pectoral fin base length
Longest pelvic fin ray length (1st)Longest 1st dorsal fin spine length (3rd)Second dorsal fin spine length
Longest 2nd dorsal fin ray length (2nd)Longest anal fin spine length (3rd)Longest anal fin ray length (2nd)Caudal peduncle length
Caudal peduncle depth
Upper caudal fin lobe length
Lower caudal fin lobe length

Holotype of
Polydactylus persicus
MCZ 60001

Paratypes of
Polydactylus persicus(n ⫽ 12)121

48–124

VIII-I, 13
III, 12
13
6
I, 5
48
5/9
15 ⫹ 20 ⫽ 35

VIII-I, 12–13 (usually 13)
III, 12
12–13
6
I, 5
46–49
5–6/8–9
12–16 ⫹ 17–20 ⫽ 29–35

31
33
33
14
4
8
9
8
19
13
36
63
66
46
28
17
17
19
29
11
17
22
7
18
8
20
21
14
35
33

31–34 (33)
33–35 (34)
32–35 (33)
13–15 (14)
4–5 (5)
7–8 (8)
8–10 (9)7–9 (8)
18–20 (19)
13–15 (14)35–38 (37)60–64 (62)64–68 (67)42–48 (46)26–28 (27)
16–19 (17)
16–18 (17)18–20 (19)26–36 (32)
10–11 (10)
16–18 (17)22–24 (23)
6–9 (7)
18–22 (21)
7–9 (8)
16–21 (20)
19–23 (21)
13–15 (14)35–40 (38)
34–44 (37)Means in parentheses include holotype data

ectopterygoids; thickness of base of second spine of firstdorsal fin slightly more robust than other first dorsal fin
spines; lateral line simple, extending from upper end ofgill opening to upper end of lower caudal fin lobe; formula for configuration of supraneural bones, anterior
neural spines, and anterior dorsal pterygiophores
0/0/0⫹2/1⫹1/1/1/1/1/; vertebrae 10 ⫹ 14.
Color in fresh.—Based on color transparencies of a
specimen that was not retained and Randall (1995, fig.
607): head and upper sides of trunk with slightly darkish

silver tinge, becoming lighter on lower sides; snout
semitranslucent; posterior margin of first and second
dorsal fins and caudal fin indistinctly blackish, other partstranslucent; pectoral fin membrane white with scatteredmelanophores; pectoral filaments whitish, becoming
blackish on posterior tips; pelvic fin whitish; a large black
spot anteriorly on lateral line.
Color of preserved specimens.—Head and body brown
dorsally, pale yellow ventrally; posterior margins of firstdorsal fin grayish-black, other parts translucent; poster-

Review of Polydactylus with large spot

iormost portions of second dorsal, anal, and caudal fins
blackish, other parts translucent; pelvic fin and pectoral
filaments pale yellow; density of pectoral fin pigmentation highly variable; a large black spot anteriorly onlateral line.
Distribution and habitat. Polydactylus persicus sp.
nov. is currently known only from the Persian Gulf (seeFig. 2).
Etymology. The name “persicus” is based on the
Persian Gulf in reference to the holotype locality.
Remarks. Polydactylus persicus sp. nov., previously
identified as P. sextarius (Kuronuma and Abe, 1972;
Randall, 1995), is regarded here as representing a new
species on the basis of its unique combination of morphological characteristics (see Discussion).

Polydactylus sextarius (Bloch andSchneider, 1801)(English name: blackspot threadfin)(Japanese name: kataguro-agonashi)(Fig. 6)Polynemus sextarius Bloch and Schneider, 1801: 18, pl. 4 (typelocality: Tranquebar, Tamil Nadu, India).
Holotype. ZMB 565, 125 mm SL, Tranquebar, Tamil Nadu,
India.
Other material. 47 specimens (57–168 mm SL), all fromeastern Indian and western Pacific Oceans. ANSP 52870,
135 mm SL, Hong Kong, China; ANSP 163038, 89 mm SL, SanTu, Fuzhou, China; BMNH 1889.2.1.3072, 73 mm SL, Cochin,
Kerala, India; BMNH 1984.1.18.245-246 (2 specimens), 81–
82 mm SL, Singapore; CSIRO C. 1002, 157 mm SL, Mambare
Bay, Papua New Guinea; FMNH 58981, 120 mm SL, Colombo,
Sri Lanka; FMNH 90768 (2), 120–121 mm SL, Rameswaram fish
market, Palk Bay, Tamil Nadu, India; FMNH 91309 (2), 125–132 mm SL, Rameswaram fish market, Palk Bay, Tamil Nadu,
India; FSKU-P 4095, 115 mm SL, Kuala Kedah fish market,
Malaysia; FSKU-P 4108, 111 mm SL, Hong Kong, China;
FSKU-P 4125, 57 mm SL, Kalangatu fish market, Serang, Java,
Indonesia; MUFS 3390, 93 mm SL, Pinang Island, Malaysia;
MUFS 14501, 105 mm SL, Songkhla, Thailand; MUFS 1562815630 (3), 128–145 mm SL, Oshima, Meitsu, Nango, Miyazaki,
Japan; MUFS 16643-16647 (5), 151–168 mm SL, Kushima,
Miyazaki, Japan; MUFS 16819-16821 (3), 120–140 mm SL,
Shanmugam fish market, Chennai (⫽Madras), Tamil Nadu,
India; MUFS 18287, 123 mm SL, Sarawak, Kalimantan, Malaysia; NTM S. 14784-006 (3), 111–120 mm SL, Gadong, Ikan Pasar,
Brunei; SFU 1669, 126 mm SL, Hainan Island, China; SFU
3833-3834 (2), 98–124 mm SL, Hong Kong, China; SFU 3835,
139 mm SL, Guangzhou, China; SFU 3871, 127 mm SL,
Dongshan, Fuzhou, China; SFU A006560, 113 mm SL,
Dongshan, Fuzhou, China; UMMZ 196223, 124 mm SL, Jakarta,
Java, Indonesia; UMMZ 219965, 142 mm SL, mouth of MekongRiver, Vietnam; URM-P 12993, 157 mm SL, Samyan market,
Thailand; URM-P 33101, 132 mm SL, Taiwan; USNM 358683,
124 mm SL, off Myanmar, northern Andaman Sea; USNM
363486, 121 mm SL, off Myanmar, northern Bay of Bengal

349(19°50⬘ N, 92°55⬘ E); YCM-P 6200, 104 mm SL, Taiwan; ZMH
13665, 86 mm SL, Java, Indonesia; ZMH 13666 (2), 67–78 mm
SL, China.

Diagnosis. A species of Polydactylus with the following combination of characters: 6 pectoral filaments, uppermost not reaching to posterior tip of pectoral fin; 13–15 (mode 14) pectoral fin rays; 45–51 (46) pored lateralline scales; 8–11 (11) scales below lateral line; 25–30 (28)gill rakers; pectoral fin rays moderate [mean 22% (range
19–25%) of SL]; second dorsal fin spine short [6% (5–8%) of SL]; all pectoral fin rays branched, except uppermost 1 or 2; vomer without teeth; swimbladder atrophied,
like a fine string; a large black spot anteriorly on lateralline.
Description. Counts and proportional measurements as percentages of SL of the holotype and otherspecimens of Polydactylus sextarius are given in Table 5.
Characters given in the diagnosis are not repeated here.
Data for the holotype are presented first, followed byother specimen data (if different) in parentheses.
Body oblong, compressed; maxilla covered with scales;
posterior margin of preopercle serrated; lower lip
well-developed; posterior margin of maxilla extending
slightly beyond (same, or not reaching) level of posterior
margin of adipose eyelid; depth of posterior portion of
maxilla less than dermal eye opening; teeth villiform,in broad bands on palatines and ectopterygoids; palatines inwardly turned anteriorly; thickness of base of
all first dorsal fin similar; lateral line simple, extending from upper end of gill opening to upper end oflower caudal fin lobe; (formula for configuration of
supraneural bones, anterior neural spines, and anterior
dorsal pterygiophores 0/0/0⫹2/1⫹1/1/1/1/1/); (vertebrae
10 ⫹ 14).
Color in fresh.—Based on color transparencies of
MUFS 15628–15630, 16643–16647 (8 specimens, 128–168 mm SL): head and upper sides of trunk with slightly
darkish silver tinge, becoming lighter on lower sides;
snout semitranslucent; posterior margin of first andsecond dorsal fins and caudal fin slightly blackish, otherparts translucent; posterior tip of anal fin whitish, otherparts blackish; pectoral fin membrane white with scattered melanophores; pectoral filaments whitish; anterior
parts of pelvic fin slightly yellowish-white, other parts
whitish; a large black spot anteriorly on lateral line.
Color of preserved specimens.—Head and body brown
dorsally, pale yellowish-silver ventrally; posterior margins of first dorsal fin black, other parts with scatteredmelanophores; posterior parts of second dorsal, anal, andcaudal fins grayish-black, other parts pale yellow with
scattered melanophores; anterior parts of pelvic fin with
scattered melanophores, other parts without melanophores; pectoral filaments pale yellow; density of pecto-

350

H. Motomura and Y. Iwatsuki

Fig. 6. Polydactylus sextarius (Bloch and Schneider, 1801). A Holotype of Polynemus sextarius Bloch and Schneider, 1801, ZMB
565, 125 mm SL, Tranquebar, Tamil Nadu, India. B Polydactylus sextarius, MUFS 16643, 164 mm SL, Kushima, Miyazaki, Japanral fin pigmentation highly variable; a large black spot
anteriorly on lateral line.
Distribution and habitat. Polydactylus sextarius is
known from the eastern Indian Ocean to western Pacific
Ocean where it ranges from southwestern India to Papua
New Guinea, and Miyazaki, Kyushu Island, Japan (see Fig.
2). Although Munro (1967) reported a single example(examined herein; CSIRO C. 1002, 157 mm SL) of thespecies collected from Papua New Guinea, P. sextarius isconsidered to occur rarely west of Huxley’s line (sensu
Whitmore, 1981), that is, in the Philippines, eastern Indonesia, including the Lesser Sunda Islands, Sulawesi Island,
Moluccas, and Irian Jaya, and Papua New Guinea, within
the limits of this investigation (see Fig. 2).

The collection data available for the species indicatedthat specimens had been taken from depths of 16–62 m.
Randall (1995) and Motomura et al. (1999) reported
specimens taken as deep as 60 m in trawls in the Bay of
Bengal and from depths of less 50 m off Miyazaki,
Kyushu Island, southern Japan, respectively.
Remarks. Fricke (1999) synonymized Polynemus
sexfilis Valenciennes in Cuvier and Valenciennes, 1831
and P. astrolabi Sauvage, 1881 under Polydactylus
sextarius. However, Polydactylus (⫽Polynemus) sexfilis is
now recognized as a valid species (Motomura et al.,2001a), and Polynemus astrolabi was synonymized with
Galeoides decadactylus (Bloch, 1795) (Motomura et al.,2001b).

Review of Polydactylus with large spot

351

Table 5. Counts and measurements of the holotype of Polynemus sextarius and non-type specimens of Polydactylus sextarius,
expressed as percentages of standard length

Standard length (mm)Counts
Dorsal fin rays
Anal fin rays
Pectoral fin rays
Pectoral filaments
Pelvic fin rays
Pored lateral line scales
Scales above/below lateral line
Gill rakers
Measurements
Head length
Body depth
Second body depth
Body width at pectoral fin base
Snout length
Dermal eye opening
Orbit diameter
Interorbital width
Postorbital length
Upper jaw lengthPre-1st dorsal fin lengthPre-2nd dorsal fin length
Preanal fin length
First dorsal fin origin to anal fin origin
Pelvic fin origin to anal fin origin
Second dorsal fin base length
Anal fin base length
Longest pectoral fin length
Longest pectoral filament length (6th)Pectoral fin base length
Longest pelvic fin ray length (1st)Longest 1st dorsal fin spine length (3rd)Second dorsal fin spine length
Longest 2nd dorsal fin ray length (2nd)Longest anal fin spine length (3rd)Longest anal fin ray length (2nd)Caudal peduncle length
Caudal peduncle depth
Upper caudal fin lobe length
Lower caudal fin lobe length

Holotype of
Polynemus sextarius
ZMB 565

Non-type specimens of
Polydactylus sextarius(n ⫽ 47)125

57–168

VIII-I, 13
III, 12
13
6
I, 5
45
6/8
11 ⫹ 17 ⫽ 28

VIII-I, 12–13 (usually 13)
III, 11–13 (usually 12)
13–15
6
I, 5
45–51
5–6/8–11
10–14 ⫹ 14–18 ⫽ 25–30

30
33
33
14
4
8
9
7
17
12
39
62
68
46
26
21
17
22
24
12
14
22
8
19
7
15
18
18
34
33

30–35 (33)
29–36 (32)
31–37 (34)
10–16 (14)
4–7 (6)
7–9 (8)
8–10 (9)7–10 (8)17–21 (19)
12–14 (13)36–41 (39)59–66 (63)
61–68 (64)
42–49 (45)
22–29 (26)
15–21 (18)
16–23 (18)
19–25 (22)
20–29 (25)
10–13 (12)
14–18 (17)21–26 (23)
5–8 (6)16–23 (19)
6–9 (8)
15–21 (17)18–24 (22)
14–18 (15)33–41 (36)
31–41 (34)Means in parentheses include holotype data

Discussion
Five Polydactylus species, P. malagasyensis sp. nov.,
P. microstomus, P. mullani, P. persicus sp. nov., and P.
sextarius, are characterized by having all pectoral fin rays
branched, except the uppermost 1 or 2, the vomer without teeth, and a large black spot anteriorly on the lateralline. Characters of the pectoral fin and coloration of thisgroup are unique among the family Polynemidae. In

addition to the group, only a single species, P. nigripinnis
Munro, 1964, has the vomer without teeth in the genus(Motomura et al., 2001a).
The above 5 species are similar to each other in overall
body appearance (see Figs. 1, 3–6). However, P. microstomus and P. mullani can be easily distinguished from theother 3 species by the number of pectoral filaments [5(rarely asymmetrically 5 and 6) and 7 (rarely asymmetrically 6 and 7), respectively, vs. 6 in the latter; Table 6].

352

H. Motomura and Y. Iwatsuki

Table 6. Frequency comparison of the numbers of pectoral fin rays and pectoral filaments in Polydactylus species with a large
anterior lateral line spot
Pectoral fin rays

P. malagasyensis
sp. nov.
P. microstomus
P. mullani
P. persicus sp. nov.
P. sextariusa

Pectoral filaments

12

13

14

15

5 on eachside

Asymmetrically
5 and 6

6 on eachside

Asymmetrically
6 and 7

7 on eachside

n ⫽ 36

—

—

36a

—

—

—

36a

—

—

n ⫽ 51n ⫽ 45n ⫽ 12n ⫽ 45

1
—
7
—

30
33
4a
8a

19a
12a
1
34

1
—
—
3

50a
—
—
—

1
—
—
—

—
—
12a
45a

—
1
—
—

—
44a
—
—

Includes holotype

Table 7. Frequency comparison of the numbers of gill rakers in Polydactylus species with a large anterior lateral line spot
Gill rakers

P. malagasyensis sp. nov.
P. microstomus
P. mullani
P. persicus sp. nov.
P. sextariusan ⫽ 35n ⫽ 51n ⫽ 44n ⫽ 12n ⫽ 45

24

25

26

27

28

29

30

31

32

33

34

35

—
2
—
—
—

—
4
—
—
2

—
6
—
—
9

—
6
—
—
13

—
5a
—
—
15a

1
14
—
2
3

6
9
—
—
3

12a
3
1
4
—

9
1
15
3
—

6
1
10
1
—

1
—
12
—
—

—
—
6a
2a
—

Includes holotype

Table 8. Frequency comparison of the numbers of pored lateral line scales and scales above and below the lateral line in
Polydactylus species with a large anterior lateral line spot
Pored lateral line scales
45
P. malagasyensis sp. nov.
P. microstomus
P. mullani
P. persicus sp. nov.
P. sextariusan ⫽ 21n ⫽ 39n ⫽ 30n ⫽ 12n ⫽ 28

—
—
—
—
3a

46
4
8
8
3
9

47
a

7
20
8
3
7

48
5
8
11
5a
6

49
3
3
2a
1
1

Scales above/below lateral line
50
1
—
1
—
1

51
1
—
—
—
1

5
n ⫽ 21n ⫽ 36n ⫽ 32n ⫽ 12n ⫽ 26

3
—
5
4a
9

6

7
a

18
34
25a
8
17a

—
2
2
—
—

/

8
—
1
—
1
3a

9
1
16
10
11a
4

10

11

a

—
—
—
—
11

20
19
22a
—
8

Includes holotype

The remaining 3 species, having 6 pectoral filaments,
P. malagasyensis sp. nov., P. persicus sp. nov., andP. sextarius, have to date been considered as conspecific(Menon, 1974; Menon and Babu Rao, 1984). However, P.
sextarius differs from the other 2 species in having an
atrophied, stringlike swimbladder (length ca. 20% of SL
vs. well-developed, ca. 40–45% of SL in the latter; Fig. 7)
and lower counts of gill rakers [mode 28 (range 25–30)
vs. 31 (29–34) in P. malagasyensis and 31 (29–35) in
P. persicus; Table 7]. Furthermore, the second dorsal fin
spine length in P. sextarius [mean 6% (range 5–8%)
of SL; Table 5] is significantly (P ⬍ 0.01) shorter thanthat of the other 2 species [7% (7–9%) of SL in P.
malagasyensis; Table 1, and 7% (6–9%) of SL in P.
persicus; Table 4].
Polydactylus malagasyensis differs from P. persicus inhaving higher counts of pectoral fin rays [14 vs. mode 12(range 12–14) in the latter; Table 6] and scales below thelateral line [10 (9–10) vs. 9 (8–9); Table 8], in addition
to the palatine being inwardly turned anteriorly (vs.
straight; Fig. 8). The posterior tip of the uppermost pectoral filament of P. malagasyensis extends slightly beyondor does not reach to the posterior tip of the pectoral fin,whereas that of P. persicus extends well beyond the latter,

Review of Polydactylus with large spot

353

Fig. 8. Ventral view of left side of oral cavity. A Polydactylus
malagasyensis sp. nov., SAM 34057 (paratype), 121 mm SL. B
P. persicus sp. nov., MCZ 60001 (holotype), 121 mm SL. ECT,
ectopterygoid; PAL, palatine; PM, premaxilla; V, vomer. Bar
5 mm

Fig. 7. Swimbladders of Polydactylus species with a large anterior lateral line spot. A P. malagasyensis sp. nov., MUFS 20381(paratype), 104 mm SL; B P. microstomus, FRLM 23518,
116 mm SL; C P. mullani, MUFS 19550, 116 mm SL; D P.
persicus sp. nov. (anteriormost tip missing), AMS I. 40432-001(paratype), 103 mm SL; E P. sextarius, MUFS 14501, 105 mm SL.
Anterior to left in each case. Bar 5 mm

because P. malagasyensis has both a longer pectoral fin[mean 24% (range 21–26%) of SL; Table 1 vs. 19% (18–20%) of SL in P. persicus; Table 4] and shorter pectoral
filaments [29% (27–31%) of SL; Table 1 vs. 32% (26–36%) of SL; Table 4]. Furthermore, the pectoral finbase length, including the pectoral filament base, of
P. malagasyensis [mean 12% (range 10–12%) of SL;
Table 1] is significantly (P ⬍ 0.01) greater than that of P.
persicus [10% (10–11%) of SL; Table 4].
Comparative material examined. Filimanus heptadactyla:
FSKU-P 19771 (2 specimens), 89–90 mm SL, Mukah fish market, Sarawak, Malaysia; NTM S. 14784-007 (2), 112–113 mm SL,
Gadong Ikan Pasar, Brunei, Kalimantan; UMMZ 213333 (2),99–106 mm SL, Pasan Ikan fish market, Jakarta, Java, Indonesia;
USNM 72741, 52 mm SL, Java, Indonesia.
Acknowledgments We greatly appreciate the following persons and institutions for specimen loans: B. Brown and X.

Freilich (AMNH); M. McGrouther and K. Parkinson (AMS);
M. Sabaj, M. Littmann, and D.D. Dagit (ANSP); J. Maclaine(BMNH); M.A. Rogers and K. Swagel (FMNH); S. Kimura(FRLM); H. Ida and M. Okamoto (FSKU-P); K. Rhode and A.
Bentley (KU); K.E. Hartel (MCZ); S.O. Kullander (NRM);
H.K. Larson, B.C. Russell, G. Dally, and S. Gregg (NTM); U.
Satapoomin (PMBC); M.J.P. van Oijen and J. van Egmond(RMNH); L. Hoenson (SAM); H.-L. Wu (SFU); D.W. Nelson(UMMZ); T. Yoshino (URM-P); S.L. Jewett, L. Palmer, S.J.
Raredon, and J.T. Williams (USNM); M. Hayashi (YCM); H.
Wilkens (ZMH). We are most grateful to H.-J. Paepke (ZMB)
for his provision of type data and a photograph of Polynemus
sextarius, W.N. Eschmeyer, T. Iwamoto, D. Catania, and J. Fong(CAS) and S.L. Jewett, L. Palmer, S.J. Raredon, and S. Smith(USNM) for the loans of the types of Polydactylus zophomus,
M.J.P. van Oijen and J. van Egmond (RMNH) for opportunities
to examine the holotype of Polynemus microstomus, A.K.
Karmakar (ZSI-F) for opportunities to examine the typesof Polynemus sextarius mullani, K. Sasaki (BSKU) for identification of Dendrophysa russelli, and Y. Fukuyo (Asian Natural
Environmental Science Center, the University of Tokyo) for
providing color photographs of Polydactylus persicus. We thankV. Lheknim and P. Pholpunthin (Faculty of Science, Princeof Songkhla University, Thailand), M.N. Venugopal and A.
Chakraborty (Department of Fishery Biology, College ofFisheries, India), B.V. Seshagiri Rao (Department of Zoology,
D.N.R. College, India), M.I. Djawad (Faculty of Marine andFishery Sciences, Hasanuddin University, Indonesia), and A.I.
Burhanuddin (MUFS) for their assistance in field work at various times. We thank Y. Motomura (Miyazaki, Japan) for her
assistance and G.S. Hardy (Thames, New Zealand), who readthe initial manuscript and offered helpful comments. This study
was supported in part by a grant awarded to the first author by
Research Fellowships of the Japan Society for the Promotion of
Science for Young Scientists (Tokyo, Japan).

Literature Cited
Ahlstrom EH, Butler JL, Sumida BY (1976) Pelagic
stromateoid fishes (Pisces, Perciformes) of the eastern

354
Pacific: kinds, distributions, and early life histories andobservations on five of these from the northwest Atlantic.
Bull Mar Sci 26:285–402
Bleeker P (1851) Nieuwe bijdrage tot de kennis der ichthyologische fauna van Celebes. Nat Tijdschr Ned-Indië 2:209–224
Bleeker P (1878) Quatrième mèmoire sur la faune ichthyologique de la Nouvelle-Guinèe. Versl Akad Amsterdam 13:35–
66
Bloch ME, Schneider JG (1801) Systema ichthyologiae
iconibus cx illustratum. Post obitum auctoris opus inchoatum
absolvit, correxit, interpolavit J. G. Schneider, Saxo Berolini.
Berolini, Berlin
Böhlke JE (1953) A catalogue of the type specimens of Recent
fishes in the Natural History Museum of Stanford University.
Stanford Ichthyol Bull 5:1–168
Feltes RM (1991) Revision of the polynemid fish genus
Filimanus, with the description of two new species. Copeia
1991:302–322
Fricke R (1999) Fishes of the Mascarene Islands (Réunion,
Mauritius, Rodriguez). An annotated checklist with descriptions of new species. Koeltz, Köenigstein
Günther A (1860) Catalogue of the acanthopterygian fishes in
the collection of the British Museum (Natural History). Vol.
2. Squamipinnes, Cirrhitidae, Triglidae, Trachinidae, Sciaenidae, Polynemidae, Sphyraenidae, Trichiuridae, Scombridae,
Carangidae, Xiphiidae. British Museum, London
Hora SL (1926) Notes on fishes in the Indian Museum. IX. Rec
Indian Mus 27:453–469
Hubbs CL, Lagler KF (1947) Fishes of the Great Lakes region.
Bull Cranbrook Inst Sci (26):i–xi ⫹ 1–186
Hubrecht AA (1879) Catalogue des collections formées etlaissées par M.-P. Bleeker. De Breuk & Smits, Leiden
Jordan DS, Richardson RE (1908) Fishes from islands of thePhilippine Archipelago. Bull Bur Fish 27:233–287
Jordan DS, Seale A (1907) Fishes of the islands of Luzon andPanay. Bull Bur Fish 26:1–48
Kagwade PV (1970) The polynemid fishes of India. Bull CentMar Fish Res Inst 18:1–69
Kuronuma K, Abe Y (1972) Fishes of Kuwait. Kuwait Institutefor Scientific Research, Kuwait
Leviton AE, Gibbs RH Jr, Heal E, Dawson CE (1985) Standards in herpetology and ichthyology: Part I. Standard
symbolic codes for institutional resource collections in herpetology and ichthyology. Copeia 1985:802–832
Mabee PM (1988) Supraneural and predorsal bones in fishes:development and homologies. Copeia 1988:827–838
Menon AGK (1974) Polynemidae. In: Fischer W, Whitehead
PJP (eds) FAO species identification sheets for fisherypurposes: eastern Indian Ocean and western central Pacific.
Fishing area 57 and 71, vol 3. FAO, Rome, pp 1–2 ⫹ “POLYN
Eleu 1” to “POLYN Poly 5”
Menon AGK, Babu Rao M (1984) Polynemidae. In: Fischer W,
Bianchi G (eds) FAO species identification sheets for fisherypurposes: western Indian Ocean. Fishing area 51, vol 3. FAO,
Rome, pp 1–2 ⫹ “POLYN Eleu 1” to “POLYN Poly 7”

H. Motomura and Y. Iwatsuki
Menon AGK, Yazdani GM (1968) Catalogue of type-specimens
in the Zoological Survey of India. Part 2. Fishes. Rec Zool
Surv India 61:91–190
Motomura H, Iwatsuki Y (2001) A new genus, Leptomelanosoma, for the polynemid fish previously known as Polydactylus indicus (Shaw, 1804) and a redescription of the species.
Ichthyol Res 48:13–21
Motomura H, Iwatsuki Y, Yoshino T, Kimura S (1999) A recordof a polynemid fish, Polydactylus sextarius, from southern
Japan (Perciformes: Polynemidae) (in Japanese). Jpn J
Ichthyol 46:57–61
Motomura H, Iwatsuki Y, Kimura S, Yoshino T (2000) Redescription of Polydactylus macrochir (Günther, 1867), a seniorsynonym of P. sheridani (Macleay, 1884) (Perciformes:
Polynemidae). Ichthyol Res 47:327–333
Motomura H, Iwatsuki Y, Kimura S (2001a) Redescriptionof Polydactylus sexfilis (Valenciennes in Cuvier andValenciennes, 1831), a senior synonym of P. kuru (Bleeker,1853) with designation of a lectotype (Perciformes:
Polynemidae). Ichthyol Res 48:83–89
Motomura H, Iwatsuki Y, Kimura S (2001b) A poorly known
polynemid fish, Polynemus astrolabi Sauvage, 1881, a juniorsynonym of Galeoides decadactylus (Bloch, 1795). Ichthyol
Res 48:197–202
Motomura H, Iwatsuki Y, Yoshino T (2001c) A new
species, Polydactylus siamensis, from Thailand and redescription of P. plebeius (Broussonet, 1782) with designation of aneotype (Perciformes: Polynemidae). Ichthyol Res 48:117–
126
Munro ISR (1967) The fishes of New Guinea. Department ofAgriculture, Stock and Fisheries, Port Moresby
Randall JE (1995) Coastal fishes of Oman. Crawford House,
Bathurst
Schroeder RE (1980) Philippine shore fishes of the western
Sulu Sea. Bureau of Fisheries and Aquatic Resources and
NMPC Books, Manila
Seale A (1910) Fishes of Borneo, with descriptions of four new
species. Philipp J Sci 5:263–289
Shen S-C (1984) Coastal fishes of Taiwan. Shih-Chieh Shen,
TaipeiShen S-C (1993) Fishes of Taiwan. National Taiwan University,
TaipeiSmith MM (1986) Polynemidae. In: Smith MM, Heemstra PC(eds) Smiths’ sea fishes. Macmillan South Africa, Johannesburg, pp 720–721
Talwar PK, Kacker RK (1984) Commercial sea fishes of India.
Zoological Survey of India, Calcutta
Trewavas E (1977) The sciaenid fishes (croakers or drums) of
the Indo-West-Pacific. Trans Zool Soc London 33:253–541
Weber M, de Beaufort LF (1922) The fishes of the IndoAustralian Archipelago, vol 4. Heteromi, Solenichthyes,
Synentognathi, Percesoces, Labyrinthici, Microcyprini.
EJ Brill, Leiden
Whitmore TC (ed) (1981) Wallace’s line and plate tectonics.
Oxford University Press, New York