Review of seven-spined Polynemus species (Perciformes:
Polynemidae) with designation of a neotype for Polynemus
paradiseus Linnaeus, 1758
Hiroyuki Motomura1*, Sven O. Kullander2, Tetsuo Yoshino3, and Yukio Iwatsuki4
1

Fish Division, Department of Zoology, National Science Museum (Natural History), 3-23-1 Hyakunin-cho, Shinjuku-ku,
Tokyo 169-0073, Japan (e-mail: motomura@kahaku.go.jp)
2
Department of Vertebrate Zoology, Swedish Museum of Natural History, P.O. Box 50007, SE-104 05 Stockholm, Sweden(e-mail: sven.kullander@nrm.se)3
Department of Marine Sciences, Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan(e-mail: b985005@sci.u-ryukyu.ac.jp)
4
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: November 7, 2001 / Revised: May 15, 2002 / Accepted: June 3, 2002

IchthyologicalResearch©The Ichthyological Society of Japan 2002

Ichthyol Res (2002) 49: 307–317

Abstract A taxonomic review of seven-spined Polynemus species recognizes two species as valid:
P. hornadayi Myers, 1936, currently known only from western Sarawak, Kalimantan, Malaysia, and P.
paradiseus Linnaeus, 1758, distributed from India to Thailand and regarded as a senior synonym of P.
aureus Hamilton, 1822, P. longifilis Cuvier in Cuvier and Valenciennes, 1829, P. risua Hamilton, 1822,
and P. toposui Hamilton, 1822. Polynemus hornadayi differs from P. paradiseus in having a strongly
protruded occipital profile (vs. nearly straight in the latter), lower counts of anal fin soft rays (mode 11
vs. 12) and gill rakers (26 vs. 32 or 33), higher counts of pectoral fin rays (18 vs. 17), scales above andbelow the lateral line (11 and 18 vs. 7 and 11, respectively), and pored lateral line scales (94 vs. 70), thefifth pectoral filament longest (vs. sixth), the fourth pectoral filament longer (extending well beyond theposterior central margin of the caudal fin vs. not reaching posterior central margin), a longer pectoral
fin ray (posterior tip of pectoral fin reaching to midpoint of anal fin base vs. not reaching), a deeper
maxilla posterior margin (mean 5% of SL vs. 4% of SL), and a well-developed swimbladder (vs.
absent).
Key words

S

Review · Polynemus hornadayi · Polynemus paradiseus · Neotype

pecies of the family Polynemidae generally have 8
spines in the first dorsal fin (Motomura et al., 1999,
2000a–c, 2001a–j, 2002; Motomura and Iwatsuki, 2001a,b).
Examination of all known available type material and original species descriptions, and also a wide range of non-type
specimens, disclosed that six nominal species belonging
to the genus Polynemus are characterized by 7 spines in
the first dorsal fin. They are P. aureus Hamilton, 1822, P.
hornadayi Myers, 1936, P. longifilis Cuvier in Cuvier andValenciennes, 1829, P. paradiseus Linnaeus, 1758, P. risua
Hamilton, 1822, and P. toposui Hamilton, 1822.
Apart from numerous brief treatments in general fishclassification and regional faunal studies, Polynemus species
with 7 spines in the first dorsal fin have never been reviewed
on the basis of type and non-type materials representing
wide distributional ranges. Thus, considerable taxonomic
confusion has resulted.
Polynemus paradiseus, the oldest available name for thefamily, was originally described from Bengal, India, on thebasis of a figure and description by Edwards (1743–1751),
and has been recognized as a valid species (Menon, 1974;
Menon and Babu Rao, 1984). Four nominal species, viz., P.

aureus, P. longifilis, P. risua, and P. toposui, are herein
regarded as junior synonyms of P. paradiseus.
A rare species, P. hornadayi, originally described from
Sarawak, Malaysia, has also been subsequently regarded asvalid (Kottelat and Lim, 1995; Randall and Lim, 2000).
However, the species has never been described in detailsince the original description. Only brief accounts havebeen published in general classificatory works and regional
faunal studies.
Both species of Polynemus characterized by 7 spines in
the first dorsal fin. Polynemus hornadayi and P. paradiseus
are herein redescribed as valid on the basis of type and nontype materials representing wide distributional ranges. In
addition, a neotype is designated for P. paradiseus.

Methods
Counts and measurements follow Hubbs and Lagler (1947)
and Motomura et al. (2000b, 2002). Counts of pectoral
filaments begin with the anterior (ventralmost) element.
Standard length is expressed as SL. Terminology of the308

supraneural bones follows Mabee (1988), and the formulafor configuration of the supraneural bones, anterior neuralspines, and anterior dorsal fin pterygiophores follows
Ahlstrom et al. (1976). Presence of a swimbladder in
Polynemus hornadayi was confirmed from USNM 321610 (8of 10 specimens), the abdomens of these fish having alreadybeen dissected. The neotype (NRM 47529) and all 4 MUFS
specimens of P. paradiseus were also dissected and theabsence of a swimbladder was confirmed. Osteologicalcharacters were confirmed from X-ray photos taken of all
specimens of each species. Institutional codes follow
Leviton et al. (1985), with additional institutional abbreviations as follows: Division of Fisheries Sciences, Faculty of

H. Motomura et al.

Agriculture, Miyazaki University, Japan (MUFS) andRaffles Museum of Biodiversity Research, Departmentof Biological Sciences, National University of Singapore(ZRC, formerly NMS). Comparative materials for this study
are listed in Motomura et al. (1999, 2000a–c, 2001a–j, 2002)
and Motomura and Iwatsuki (2001a,b).

Polynemus hornadayi Myers, 1936
(English name: Hornaday’s paradise fish)(Figs. 1, 2, 3A,B, 6A, 7, 8; Tables 1, 3–5)
Polynemus hornadayi Myers, 1936: 376, fig. 1 [type locality: EnsengiRiver (tributary of Sadong River), Sarawak, Kalimantan, Malaysia].

Fig. 1. Polynemus hornadayi Myers, 1936. A Holotype, USNM 100632, 193 mm SL, Ensengi River (emptying into Sadong River), Sarawak,
Kalimantan, Malaysia. B Non-type specimen, USNM 321610, 178 mm SL, Sunday Dayak market at Kuching, Sarawak, Kalimantan, Malaysia

Review of the seven-spined Polynemus

309

Table 1. Counts and measurements of Polynemus hornadayi, including the holotype, paratypes, and non-type specimens, expressed as percentagesof 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 (means)
Head length
Body depth at 1st dorsal fin origin
Body depth at 2nd dorsal fin origin
Body width at pectoral fin base
Snout length
Dermal eye opening
Orbit diameter
Interorbital width
Postorbital length
Upper jaw length
Depth at posterior margin of maxilla
Pre-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 baseLongest pelvic fin ray length (1st)Longest 1st dorsal fin spine length (2nd)Second dorsal fin spine length
Longest 2nd dorsal fin ray length (2nd)Longest anal fin spine length (2nd or 3rd)Longest anal fin ray length (2nd)Caudal peduncle length
Caudal peduncle depth
Upper caudal fin lobe length
Lower caudal fin lobe length

Holotype
USNM 100632

Paratypesn⫽9

Non-type specimensn ⫽ 16193

109–146

94–201

VII–I, 15
II, 12
18
7
I, 5
92
11/19
10 ⫹ 16 ⫽ 26

VII–I, 15–16
II–III, 11–12
16–18
7
I, 5
90–99
8–12/18–20
10–11 ⫹ 16–17 ⫽ 26–28

VII–I, 14–16
II–III, 11–12
17–19
7
I, 5
90–103
10–12/16–21
10–11 ⫹ 16–17 ⫽ 26–28

28
25
25
13
7
1
3
9
20
15
5
35
60
63
41
30
20
15
43
Damaged
15
18
Damaged
7
19a
8
21
25
11
Damaged
36a

27–28
24–25
22–25
12–14
6–7
1–2
2–3
9
20
13–15
5
34–35
59–62
59–64
38–41
27–31
18–20
13–16
40–42
Damaged
13–15
18–19
18–20
7–9
22–24
7–10
19–22
25–28
10–11
43
40–43

26–29 (28)
24–30 (26)
23–27 (25)
13–17 (14)
6–7 (7)
1–2 (1)2 (2)9–10 (9)18–21 (20)
13–16 (14)
4–5 (5)34–39 (36)
58–63 (60)
58–63 (61)38–43 (40)
27–32 (29)
19–22 (20)
12–17 (14)39–47 (42)323–339 (331)
14–15 (14)19–22 (20)
19–20 (20)
7–9 (8)
21–25 (23)
6–10 (9)20–24 (22)26–31 (27)
10–11 (11)
41–46 (44)37–46 (41)

Means in parentheses include data of type specimensaSlightly damaged at tip
Holotype. USNM 100632, 193 mm SL, Ensengi River (tributary of
Sadong River), Sarawak, Kalimantan, Malaysia, 2 Oct. 1877, collectedby W.T. Hornaday.
Paratypes. 9 specimens, 109–146 mm SL. BMNH 1935.8.29.31,
142 mm SL, same data as holotype; USNM 35719 (8 specimens), 109–
146 mm SL, same data as holotype.
Other material. 16 specimens, 94–201 mm SL. MCZ 313497,
126 mm SL, Sungai River at Kota Samarahan (about 20 km southeastof Kuching), Sarawak, Kalimantan, Malaysia; NMS at ZRC 2883 (3),
121–201 mm SL, Stambak Saribas, Sarawak, Kalimantan, Malaysia;

USNM 321610 (10), 166–188 mm SL, Sunday Dayak market at
Kuching, Sarawak, Kalimantan, Malaysia; ZRC 39739, 94 mm SL,
Sungai River at Kota Samarahan, Sarawak, Kalimantan, Malaysia;
ZRC 46032, 173 mm SL, Kapit, Rajang River, Sarawak, Kalimantan,
Malaysia.

Diagnosis. A species of Polynemus with the following
combination of characters: 7 first dorsal fin spines; 14–16(mode 15) dorsal fin soft rays; 7 pectoral filaments, fifth
longest and fourth extending well beyond posterior central

310

margin of caudal fin; 16–19 (18) pectoral fin rays; 2 or 3
(3) anal fin spines; 11 or 12 (11) anal fin soft rays; 90–103(94) pored lateral line scales; 8–12 (11) scale rows above
lateral line, 16–21 (18) below; 10 or 11 (10) upper series
gill rakers, 16 or 17 lower, 26–28 (26) total; occipitalprofile strongly protruding; vomer with villiform teeth; pectoral fin long [mean 42% (range 39–47%) of SL], posterior
tip reaching to midpoint of anal fin base; posterior portionof maxilla deep [5% (4–5%) of SL]; swimbladder present,
large.
Description. Counts and proportional measurements aspercentages of SL of the holotype and other material of
Polynemus hornadayi are given in Table 1. Characters givenin the species diagnosis are not repeated here. Data for theholotype are presented first, followed by other material data
(if different) in parentheses.
Body oblong, compressed; maxilla covered with scales;
lip on lower jaw well developed; posterior margin of
preopercle serrated; posterior margin of maxilla extending
well beyond level of posterior margin of adipose eyelid;
teeth villiform in broad bands on palatines and ectopterygoids; all pectoral fin rays unbranched, inserted nearbody midline; fifth to seventh pectoral filaments (fifth
longest) longer than total length (filaments tips easily
damaged); fourth pectoral filament slightly longer thanstandard length (same or slightly shorter); third pectoral
filament reaching to near level of posterior end of anal
fin base (same or reaching between levels of origin andposterior end of anal fin base); second pectoral filament
not reaching to level of anal fin origin; first pectoral
filament shortest, not reaching to level of posterior tip ofpelvic fin; all first dorsal fin spine bases of similar thickness;lateral line simple, extending from upper end of gill
opening to middistal margin of caudal fin membrane;
formula for configuration of supraneural bones, anterior
neural spines, and anterior dorsal pterygiophores /0/0⫹1/1⫹1/1/1/1/1/ (same or /0/0⫹1/1/1⫹1/1/1/1/); 10 ⫹ 15vertebrae.
Color of preserved specimens.—Head and body grayishblack dorsally, pale yellowish-silver ventrally (bodyuniformly grayish-black in older preserved specimens,
including holotype); membranes of first dorsal fin translucent, spines pale yellow; bases of second dorsal, pectoral,
pelvic, anal, and caudal fins pale yellow, posterior marginsof these fins translucent; pectoral filaments uniformly
whitish-yellow.
Distribution. Polynemus hornadayi is currently known
only from three rivers, the Ensengi, Rajang, and Sungai
Rivers, in western Sarawak, Kalimantan, Malaysia (Fig. 2).
The species inhabits only freshwater regions of these rivers,
having never been recorded from the estuarine areas
behind the river mouths.
Remarks. Polynemus hornadayi Myers, 1936 wasdescribed as a new species on the basis of 11 specimens(holotype and 10 paratypes) from the Ensengi River, atributary of the Sadong River, Sarawak, Kalimantan,
Malaysia. One and 8 paratypes are now registered as
BMNH 1935.8.29.31 and USNM 35719, respectively, theremaining paratype apparently having been lost.

H. Motomura et al.

Fig. 2. Localities of specimens of Polynemus hornadayi (stars) and P.
paradiseus (circles) examined in this study

Fig. 3. First pterygiophore of first dorsal fin in Polynemus hornadayi (AUSNM 321610, 170 mm SL; B MCZ 313497, 126 mm SL), and P. dubius(C URM-P 13930, 136 mm SL). Bars 5 mm

In the original description of Polynemus hornadayi,
Myers (1936) described the species as having 94–97 pored
lateral line scales, 8–9 scale rows above the lateral line, and
12 and 15 gill rakers in the upper and lower series, respectively. However, reexamination of the holotype and 9paratypes in this study revealed that the types actually have
90–99 pored lateral line scales, 8–12 scale rows above thelateral line, and 10–11 and 16–17 gill rakers in the upper andlower series, respectively.
Polynemus hornadayi and P. paradiseus Linnaeus,
1758 (below) both have 7 first dorsal fin spines, whereas allother polynemid species have 8 spines (Motomura et al.,1999, 2000a–c, 2001a–j, 2002; Motomura and Iwatsuki,
2001a,b; Fig. 3). However, radiographs of P. hornadayi
indicate that 4 of 26 specimens have a grain of oval bone
(diameter less than ca. 1 mm) buried under the subcutaneous tissue in front of the first dorsal fin spine and associated with the first pterygiophore (Fig. 3B). Although theanteriormost dorsal fin spine of other polynemid species isalso small, the spine is conventionally “spine-shaped” (notoval) with a dorsally exposed tip (Motomura et al., 2001b:
fig. 4; Fig. 3C). The oval bone associated with the firstpterygiophore in some P. hornadayi is considered to represent the final stages of degeneration from an original
spine precursor.

Review of the seven-spined Polynemus

Polynemus paradiseus Linnaeus, 1758
(English name: paradise threadfin)(Figs. 2, 4, 5, 6B, 7, 8; Tables 2, 3–5)
Polynemus paradiseus Linnaeus, 1758: 317 [original locality: Bengal,
India, based on the figure (see Fig. 5) and description of Edwards(1743–1751); type locality (of newly designated neotype): Gariahat,
Calcutta, West Bengal, India].
Polynemus risua Hamilton, 1822: 228, 381 (type locality: vicinity ofLukhipur, India).
Polynemus toposui Hamilton, 1822: 232, 381 (type locality: estuary ofGanges River, West Bengal, India; original drawing reproduced in
Hora, 1929: pl. 16, fig. 1).
Polynemus aureus Hamilton, 1822: 232, 381 (type locality: Calcutta,
West Bengal, India).
Polynemus longifilis Cuvier in Cuvier and Valenciennes, 1829: 365 [typelocality: Pondicherry and Ganges River, India; Manila, Philippines(probably erroneous, see Distribution)].
Neotype. NRM 47529, 198 mm SL, Gariahat, Calcutta, West Bengal,
India, 24 Mar. 2000, collected by H. Motomura and Y. Iwatsuki.
Other material. 41 specimens, 72–182 mm SL. AMNH 217854 (3specimens), 134–144 mm SL, San Pya fish market, Yangon, Myanmar;
ANSP 11498 (2), 135–147 mm SL, Indonesia; ANSP 85770, 101 mm SL,
Mumbai, Maharashtra, India; ANSP 87575, 137 mm SL, Mumbai,
Maharashtra, India; MCZ 16313 (4), 131–147 mm SL, Thailand; MHNG
148.24 (syntype of Polynemus longifilis Cuvier in Cuvier andValenciennes, 1829), 134 mm SL, Ganges River, West Bengal, India;
MNHN 2200 (3 syntypes of P. longifilis), 141–157 mm SL, Ganges River,West Bengal, India; MNHN A. 3045 (syntype of P. longifilis), 115 mm SL,
Manila, Philippines (locality probably erroneous, see Distribution);
MNHN A. 4803 (dried syntype of P. longifilis), 154 mm SL, Pondicherry,
India; MUFS 19051–19052 (2), 154–166 mm SL, Gariahat, Calcutta, West
Bengal, India; MUFS 19065–19066 (2), 150–155 mm SL, Namkhana,West Bengal, India; NRM 3483, 110 mm SL, West Bengal, India; SMF 439

311(syntype of P. longifilis), 124 mm SL, Ganges River, West Bengal, India;
USNM 343563 (3 of 12), 108–113 mm SL, Yangon fish market, Myanmar;
USNM 363714 (2), 100–107 mm SL, off Myanmar (21°00⬘ N, 91°59⬘ E);
USNM 363715 (4), 93–124 mm SL, off Bangladesh (21°43⬘ N, 91°33⬘ E);
USNM 363716 (6), 116–126 mm SL, off Bangladesh (21°32⬘ N, 91°29⬘ E);
URM-P 10846, 182 mm SL, Hooghly River, West Bengal, India; URM-P
10905, 72 mm SL, Hooghly River, West Bengal, India; URM-P 29087,
145 mm SL, Bangkok, Thailand.

Diagnosis. A species of Polynemus with the following
combination of characters: 7 first dorsal fin spines; 14–15(mode 15) dorsal fin soft rays; 7 pectoral filaments, sixth
longest and fourth not reaching to posterior central marginof caudal fin; 15–18 (17) pectoral fin rays; 2 anal fin spines;
11–13 (12) anal fin soft rays; 66–71 (70) pored lateral line
scales; 6 or 7 (7) scale rows above lateral line, 10–12 (11)below; 12–14 (13) upper series gill rakers, 17–20 (20) lower,
30–34 (32 or 33) total; occipital profile nearly straight;
vomer with villiform teeth; pectoral fin short [mean 33%(range 30–35%) of SL]; posterior tip of pectoral fin reachingto (or just short of) level of anal fin origin [but in juveniles(less than ca. 100 mm SL) extending slightly beyond anal fin
origin]; posterior portion of maxilla shallower [4% (3–4%)
of SL]; swimbladder absent.
Description. Counts and proportional measurements aspercentages of SL of the neotype and other material of
Polynemus paradiseus, and syntypes of P. longifilis are given
in Table 2. Characters given in the species diagnosis are notrepeated here. Data for the neotype are presented first,
followed by other material data (if different) in parentheses.
Body oblong, compressed; maxilla covered with scales;
lip on lower jaw well-developed; posterior margin of
preopercle serrated; posterior margin of maxilla extending

Fig. 4. Neotype of Polynemus paradiseus Linnaeus, 1758 (NRM 47529, 198 mm SL, Gariahat, Calcutta, West Bengal, India)

312

H. Motomura et al.

Table 2. Counts and measurements of the neotype and non-type specimens of Polynemus paradiseus, and syntypes of P. longifilis, expressed aspercentages 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 (means)
Head length
Body depth at 1st dorsal fin origin
Body depth at 2nd dorsal fin origin
Body width at pectoral fin base
Snout length
Dermal eye opening
Orbit diameter
Interorbital width
Postorbital length
Upper jaw length
Depth at posterior margin of maxilla
Pre-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 baseLongest pelvic fin ray length (1st)Longest 1st dorsal fin spine length (2nd)Second dorsal fin spine length
Longest 2nd dorsal fin ray length (2nd)Longest anal fin spine length (2nd)Longest anal fin ray length (2nd)Caudal peduncle length
Caudal peduncle depth
Upper caudal fin lobe length
Lower caudal fin lobe length

Neotype of P. paradiseus
NRM 47529

Syntypes of P. longifilisn ⫽ 7aNon-type specimens of P. paradiseusn ⫽ 34198

115–157

72–182

VII–I, 15
II, 12
16
7
I, 5
70
7/12
13 ⫹ 20 ⫽ 33

VII–I, 15
II, 12
16–18
7
I, 5
67–70
6–7/10–12
12–14 ⫹ 18–20 ⫽ 30–34

VII–I, 14–15
II, 11–13
15–18
7
I, 5
66–71
6–7/10–12
12–14 ⫹ 17–20 ⫽ 30–34

25
26
27
15
6
1
2
8
18
13
4
34
58
61
39
30
20
17
33
181b
12
17c
18
6
18
7
17
27
12
36
33

25–26
20–24
22–23
12–13
6
2
2–3
9
17–18
13–15
3–4
34–35
57–59
57–63
35–37
27–33
19–21
14–16
30–34
171–243
11–13
14–16
14–18
7–8
20–21
7–8
17–19
25–28
9–11
39–44
35–40

24–27 (26)
20–28 (24)
21–28 (24)
11–16 (14)
6–7 (6)
1–2 (2)
2–3 (2)
8–10 (9)17–19 (18)
13–15 (14)
3–4 (4)30–36 (34)
57–61 (58)
56–61 (59)35–41 (37)
25–31 (28)
18–21 (20)
15–17 (16)30–35 (33)
181–248 (208)
13–14 (13)15–18 (16)
17–20 (18)
5–8 (7)
18–24 (21)
7–10 (8)17–22 (19)26–29 (28)
9–12 (10)39–49 (44)33–47 (40)

Means in parentheses include data of type specimensaIncluding a dried specimen (MNHN A. 4803)b
Slightly damaged at tip
cMeasurement made on right side of the body

well beyond level of posterior margin of adipose eyelid;
teeth villiform in broad bands on palatines and ectopterygoids; all pectoral fin rays unbranched, inserted nearbody midline; fifth to seventh pectoral filaments (sixth
longest), longer than total length (filament tips easily
damaged); fourth pectoral filament reaching near levelof posterior base of anal fin (same or just reaching to caudal
fin base); third pectoral filament not reaching to level ofanal fin origin (same or just reaching); second pectoral
filament not reaching to level of posterior tip of pelvic fin(same or extending slightly beyond); first pectoral filament
shortest, not reaching to level of posterior tip of pelvic fin;
all first dorsal fin spine bases of similar thickness; lateralline simple, extending from upper end of gill opening to
middistal margin of caudal fin membrane; formula for
configuration of supraneural bones, anterior neural spines,

Review of the seven-spined Polynemus

and anterior dorsal pterygiophores /0/0⫹1/1/1⫹1/1/1/1/;
10 ⫹ 15 vertebrae.
Color when fresh.—Based on neotype (NRM 47529,
198 mm SL): head and body grayish-black dorsally, yellow
ventrally; anterior parts of first and second dorsal fins
grayish-black, other parts pale yellow; pectoral and pelvic
fins uniformly vivid yellow; base of pectoral filaments vivid
yellow, becoming whitish-yellow on posterior tips; anal fin
uniformly yellow; posterior margin of caudal fin yellow,
other parts grayish-black.
Color of preserved specimens.—Head and body grayishblack dorsally, pale yellowish-silver ventrally (body uniformly white in older preserved specimens); membranes
between first and third spines of first dorsal fin dense black,membranes of other parts white; first to third spines of firstdorsal fin grayish-black, other spines pale yellow; anterior
margin and base of second dorsal fin dark yellow and posterior margin pale yellow; pectoral fin pale yellow or translucent (intensity of pectoral fin pigmentation variable, rarely
posterior parts of pectoral fin dense black (pigmentation
lacking in neotype with no pigmentation); bases of pectoral
filaments whitish-yellow, becoming grayish-black on posterior tips (grayish-black on tips of pectoral filaments often
lost in older preserved specimens); pelvic and anal finsuniformly pale yellow; posterior margin of caudal fin
whitish-yellow, other parts pale yellow.
Distribution and habitat. Polynemus paradiseus is currently known from the eastern Indian to the western Pacific
Ocean, where it ranges over continental shelves from western India to Thailand (based on specimens examined during
this investigation; see Fig. 2). Two specimens (ANSP 11498,
135–147 mm SL) collected (probably pre-1900) fromIndonesia by H.C. Wood, lacked detailed locality and othercollection data. An Indonesian distribution of the species
therefore needs reconfirmation and, accordingly, has been
omitted from the distribution map (Fig. 2). Furthermore,
Blanc and Hureau (1971) indicated in the type catalogue of
Muséum National d’Histoire Naturelle that a syntype of P.
longifilis (MNHN A. 3045, 115 mm SL) had been collectedfrom Manila, Philippines. However, because P. longifilis(⫽P. paradiseus, see Remarks) has currently been recorded only from continental shelf areas, including India,
Bangladesh, Myanmar, and Thailand, the Philippines
locality of the syntype is likely to have been erroneous.
The available collection data indicated that P. paradiseus
specimens had been collected from fresh, estuarine, andoffshore waters (from depths of less than 25 m). Although P.
paradiseus is known to regularly enter freshwater (limited
to spawning season only; David, 1954), the species is considered to be more heavily dependent on marine and brackish
habitats, compared with other congeners that generally
inhabit completely freshwater basins (Motomura et al.,
2001j).
Remarks. Polynemus paradiseus Linnaeus, 1758, oneof three of the oldest available names in the family
Polynemidae, was described on the basis of a figure (Fig. 5)
and description given by Edwards (1743–1751), who briefly
described the figured fish (collected from Bengal, India by
Dr. Mead) as the “Mango-Fish.” The specimen used for313

Fig. 5. Drawing of the “Mango-Fish” of Edwards (1743–1751)

Edwards’ figure and description apparently no longer exists.
However, Edwards’ figure (Fig. 5) clearly indicates 7 spines
in the first dorsal fin and 7 pectoral filaments, the uppermost
3 extending beyond the posterior tips of the caudal fin lobes
and fourth pectoral filament not extending beyond thecaudal fin base. The characters of the specimens consideredhere as P. paradiseus agree well with those shown on the
figure.
Subsequently, Hamilton (1822) described three new
species with 7 pectoral filaments, Polynemus risua, P.
toposui, and P. aureus, all from India, but gave no indicationof any type specimens. In fact, Hamilton’s (1822) monograph of the Gangetic fishes is based only on drawings andfield notes. He did not preserve any specimens of the species
he described, including the types of the aforenamed three
species (Hora, 1929). According to their original descriptions (Hamilton, 1822), all three species were characterizedby having 7 long pectoral filaments and 7 first dorsal fin
spines, but differed from each other in the numbers of dorsal fin soft rays (17 in P. risua, 16 in P. toposui, and 15 in P.
aureus), pectoral fin rays (17, 16, and 17, respectively), andanal fin rays (including spines; 15, 16, and 14, respectively).
However, these fin ray numbers are almost wholly within
the range of intraspecific variation found during the present
study (see Tables 2, 3), based on a large number of specimens. The diagnostic characters of 7 long pectoral filaments
and 7 first dorsal fin spines given in the original descriptions(supported by the collection locality) of these species are
consistent with those of P. paradiseus. Accordingly, P. risua,
P. toposui, and P. aureus are herein regarded as juniorsynonyms of P. paradiseus.
Although Fricke (1999) believed P. longifilis to be a juniorsynonym of Polydactylus plebeius (Broussonet, 1782), being
widely distributed in the Indo-Pacific (Motomura et al.,2001c), the syntypes of the former clearly differ fromexamples of the latter, including the neotype, in having 7
pectoral filaments (longer than SL vs. 5, shorter than SL in
the latter) and the orbit diameter smaller than the posterior
depth of the maxilla (vs. larger) (see Motomura et al.,

314

H. Motomura et al.

Table 3. Frequency comparison of dorsal fin soft ray, anal fin spine and soft ray, and pectoral fin ray numbers in seven-spined Polynemus species

P. hornadayi
P. paradiseusabn ⫽ 26n ⫽ 40Dorsal fin soft rays

Anal fin spines

Anal fin soft rays

Pectoral fin rays

14

15

16

2

3a

11

12

13

15

16

17

18

19

1
8

17b
32b

8
—

10
40b

16b
—

22
1

4b
38b

—
1

—
2

1
17b

10
18

14b
3

1
—

First of 3 spines vestigial, confirmed by radiograph
Includes holotype of P. hornadayi or neotype of P. paradiseus

Table 4. Frequency comparison of scales above and below lateral line and pored lateral line scale numbers in seven-spined Polynemus species
Scales above/below lateral line

P. hornadayi
P. paradiseusn ⫽ 24n ⫽ 28

6

7

8

9

10

11

12

—
6

—
22a

1
—

2
—

7
—

11a
—

3
—

/

10

11

12

—

16

17

18

19

20

21

—
6

—
19

—
3a

—
—

2
—

2
—

10
—

6a
—

3
—

1
—

Pored lateral line scales

P. hornadayi
P. paradiseusan ⫽ 25n ⫽ 33

66

67

68

69

70

71

—

90

91

92

93

94

95

96

97

98

99

—

103

—
2

—
4

—
8

—
7

—
11a

—
1

—
—

3
—

2
—

2a
—

2
—

5
—

2
—

3
—

1
—

3
—

1
—

—
—

1
—

Includes holotype of P. hornadayi or neotype of P. paradiseus

Table 5. Frequency comparison of gill raker numbers in seven-spined Polynemus species
Upper limb

P. hornadayi
P. paradiseusan ⫽ 26n ⫽ 40Lower limb

Total

10

11

12

13

14

16

17

18

19

20

26

27

28

29

30

31

32

33

34

19a
—

7
—

—
17

—
19a

—
4

13a
—

13
1

—
8

—
14

—
17a

12a
—

8
—

6
—

—
—

—
8

—
7

—
11

—
11a

—
3

Includes holotype of P. hornadayi or neotype of P. paradiseus

2001c). Examination of the syntypes of P. longifilis showed
them to correspond closely with the specimens consideredhere as P. paradiseus. Accordingly, P. longifilis is also regarded as a junior synonym of P. paradiseus. The meristic
and morphological characters of the types of P. longifilis areincluded in Table 2.
The proposal of a neotype for P. paradiseus is hereinjustified as being necessary to avoid taxonomic confusion,owing to the similarity of that species to other congeners.
Polynemus paradiseus was originally described from
Bengal, India (detailed locality not given; Edwards, 1743–
1751; Linnaeus, 1758). A specimen (NRM 47529, 198 mm
SL) collected from Gariahat, Calcutta, West Bengal, India isherein proposed as the neotype for the species. Accordingly,
Gariahat, Calcutta becomes the type locality of P. paradiseus under Article 76.3 (ICZN, 1999).
Comparison. Polynemus hornadayi and P. paradiseus
are clearly distinguished from other members of the family
Polynemidae, including other congeners, by having 7 dorsal
fin spines (vs. 8 in the latter). At a glance, the two species canbe easily distinguished from each other by the shape of theoccipital profile, that of P. hornadayi protruding strongly
whereas that of P. paradiseus is nearly straight throughout
life (Figs. 1, 4, 6).
In meristic characters, P. hornadayi differs from P.
paradiseus in having lower counts of anal fin soft rays [mode11 (range 11–12) vs. 12 (rarely 11 or 13) in the latter; see
Table 3] and gill rakers [26 (26–28) vs. 32 or 33 (30–34);
Table 5], and higher counts of pectoral fin rays [18 (16–19)
vs. 17 (15–18); Table 3], scales above and below the lateralline [11 (8–12) and 18 (16–21) vs. 7 (6 or 7) and 11 (10–12),
respectively; Table 4], and pored lateral line scales [94 (90–103) vs. 70 (66–71); Table 4].
While P. hornadayi is similar to P. paradiseus in having 7
pectoral filaments (Tables 1, 2), in the former the fifth pectoral filament is the longest [mean 331% (range 323–339%)
of SL; see Table 1] and the fourth filament extends wellbeyond the posterior central margin of the caudal fin,whereas in the latter the sixth filament is the longest [208%(181–248%) of SL; Table 2] and the fourth filament fails toreach the posterior central margin of the caudal fin. The
pectoral fin of P. hornadayi is also relatively longer than that

Review of the seven-spined Polynemus

315

Fig. 6. Juveniles of Polynemus hornadayi (A ZRC 39739, 94 mm SL)
and P. paradiseus (B URM-P 10905, 72 mm SL)

Fig. 8. Relationships of A head length, B postorbital length, C pectoralfin (PF) base length, and D pelvic fin ray length to standard length in
Polynemus hornadayi (stars) and P. paradiseus (circles)

Fig. 7. Relationships of A pectoral fin length and B depth at posterior
margin of maxilla to standard length in Polynemus hornadayi (stars)
and P. paradiseus (circles)of P. paradiseus [posterior tip of pectoral fin reaching to
midpoint of anal fin base, 42% (39–47%) of SL vs. notreaching, 33% (30–35%) of SL, respectively; Tables 1, 2, Fig.
7A]. Furthermore, the posterior margin of the maxilla of P.

hornadayi is deeper than that of P. paradiseus [5% (4–5%)
of SL vs. 4% (3–4%) of SL, respectively; Tables 1, 2, Fig. 7B],
P. hornadayi also tending to have a slightly longer head
[28% (26–29%) of SL], postorbital [20% (18–21%) of SL],and pectoral fin base [14% (14–15%) of SL], and greater
pelvic fin ray lengths [20% (19–22%) of SL] than P.
paradiseus [27% (24–27%), 18% (17–19%), 13% (13–14%),and 16% (15–18%) of SL, respectively], although theproportional length measurements overlapped between thetwo species (Tables 1, 2, Fig. 8).
Internally, P. hornadayi differs from P. paradiseus inhaving a well-developed swimbladder (absent in the latter).
Furthermore, the former frequently has a vestigial anal fin
spine buried under subcutaneous tissue (62%, 16 of 26
specimens), such being absent in P. paradiseus (see Table 3).
Acknowledgments We are greatly appreciative to the following forspecimen loans: B. Brown and X. Freilich (AMNH), M.H. Sabaj, M.
Littmann, and D. Dagit (ANSP), J. Maclaine (BMNH), K.E. Hartel(MCZ), S.L. Jewett, L. Palmer, S.J. Raredon, S. Smith, and J.T. Williams(USNM), and P.K.L. Ng and K.K.P. Lim (ZRC). We are most grateful to
C. Weber (MHNG) and M. Gudo (SMF) for their provision of type data

316

H. Motomura et al.

and photographs of Polynemus longifilis, and to P. Pruvost (MNHN)
and S.L. Jewett, L. Palmer, S.J. Raredon, and S. Smith (USNM) for
opportunities to examine the types of P. longifilis and P. hornadayi,
respectively. We thank M.N. Venugopal and A. Chakraborty (Department of Fishery Biology, College of Fisheries, India), B.V. Seshagiri Rao(Department of Zoology, D.N.R. College, India), and A. Choochern(Bangkok, Thailand) for their assistance in fieldwork at various times.
We thank Y. Motomura (Hiratsuka, Japan) for her assistance and G.S.
Hardy (Ngunguru, New Zealand), who read the initial manuscript andoffered helpful comments. This study was supported in part by a grantawarded to the first author by Research Fellowships of the Japan
Society for the Promotion of Science for Young Scientists (Tokyo,
Japan).

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