A new subspecies, Polynemus melanochir dulcis, from Tonle
Sap Lake, Cambodia, and redescription of P. m. melanochir
Valenciennes in Cuvier and Valenciennes, 1831
with designation of a neotype
Hiroyuki Motomura1* and Mark H. Sabaj2
1Fish 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 Ichthyology, Academy of Natural Sciences, 1900 Benjamin Franklin Parkway, Philadelphia, PA 19103-1195,
USA (e-mail: sabaj@discovery.acnatsci.org)
Received: September 27, 2001 / Revised: December 20, 2001 / Accepted: December 29, 2001

IchthyologicalResearch©The Ichthyological Society of Japan 2002

Ichthyol Res (2002) 49: 181–190

Abstract A poorly known threadfin, Polynemus melanochir Valenciennes in Cuvier and Valenciennes,
1831, is redescribed (as P. melanochir melanochir) on the basis of a newly designated neotype and alarge number of specimens. Polynemus melanopus Sauvage, 1881 and 3 species commonly regarded asvalid, Galeoides microps Steindachner, 1869, P. borneensis Bleeker, 1857, and Trichidion hilleri Fowler,
1905, are all considered junior synonyms of P. m. melanochir. In addition, a new subspecies, P.
melanochir dulcis, is described on the basis of 3 specimens. Polynemus m. dulcis differs from P. m.
melanochir in having a greater snout length [7% of SL vs. mean 6% (range 5–6%) of SL in the latter]and shorter upper caudal-fin lobe length [35% (34–35%) of SL vs. 39% (35–44%) of SL]. The former
is currently known only from Tonle Sap Lake, Cambodia, whereas the latter is known from the MekongRiver (Cambodia and southern Vietnam) and Kalimantan (⫽Borneo; Malaysia and Indonesia).
Key words Polynemidae · Polynemus melanochir dulcis ssp. nov. · Polynemus melanochir melanochir ·Neotype · SynonymyP

olynemus melanochir was originally described by
Valenciennes in Cuvier and Valenciennes (1831) on thebasis of an anonymous drawing (reproduced in Feltes,
1991). Subsequently, many researchers (e.g., Bleeker, 1849;
Myers, 1936; Gloerfelt-Tarp and Kailola, 1984) havemisidentified a separate species (later described as
Filimanus perplexa Feltes, 1991) as P. melanochir (Feltes,
1991). Recently, Feltes (1991) and Randall and Lim (2000)
correctly identified P. melanochir but gave no description of
the species and no indication of specimens. Thus, the taxonomic identity of P. melanochir remains confusing.
Polynemus borneensis Bleeker, 1857, originally describedon the basis of 3 specimens from Banjarmasin, Pontianakand Sampit, Kalimantan (⫽Borneo), Indonesia, andTrichidion hilleri Fowler, 1905, originally described on thebasis of a single specimen from Baram River, Sarawak,
Kalimantan, Malaysia, have both been regarded as valid
species (e.g., Weber and de Beaufort, 1922; Kottelat et al.,
1993; Rainboth, 1996 in the former; Kottelat et al., 1993;
Kottelat and Lim, 1995 in the latter). However, our examinations of the types of both species and other specimens
considered here to be P. melanochir showed that they represented a single species diagnosed by the absence of teethon the vomer and an intense black pectoral fin. Accordingly,
P. borneensis and T. hilleri are herein regarded as juniorsynonyms of P. melanochir.

Galeoides microps Steindachner, 1869, originally described on the basis of a single specimen from China, also
has been regarded as a valid species of Galeoides (e.g.,
Fowler, 1935; Myers, 1936; Springer, 1982; Hureau, 1986).
Recently, Motomura et al. (2001) examined the holotypeof this species and regarded it as a junior synonym of P.
melanochir.
Polynemus melanopus Sauvage, 1881, originally describedon the basis of 4 specimens from Saigon (⫽Ho-chi-minh),
Vietnam, has not been reported since its original description. The defining characters, vomer without teeth and black
pectoral fin, of the types of this species were found to
be consistent with those of P. melanochir. Accordingly, P.
melanopus also is regarded as a junior synonym of P.
melanochir.
During examination of specimens of P. melanochir, 3
specimens from Tonle Sap Lake, Cambodia, were noted in
the BSKU collection. As does P. melanochir, these specimens also lack teeth on the vomer and have a black pectoral
fin; however, they differed from P. melanochir in having
a greater snout length and shorter upper caudal-fin lobe
length. These specimens are considered to represent a
distinct subspecies of P. melanochir, herein described as P.
m. dulcis. The nominal P. m. melanochir is redescribed (as asenior synonym of G. microps, P. borneensis, P. melanopus,
and T. hilleri), and a neotype is newly designated.

182

H. Motomura and M.H. Sabaj

Methods
Counts and measurements followed Hubbs and Lagler(1947), Motomura et al. (2000), and Motomura and Iwatsuki(2001). Counts of pectoral filaments began with the anterior
or ventralmost element. Standard length and total length
were expressed as SL and TL, respectively. Terminology ofsupraneural bones followed Mabee (1988); the formula for
configuration of supraneural bones, anterior neural spines,
and anterior dorsal-fin pterygiophores followed Ahlstrom etal. (1976). Osteological characters were confirmed from Xray photographs taken of all specimens, except the holotypeof Galeoides microps and syntypes of Polynemus melanopus.
Institutional codes followed Leviton et al. (1985), with additional institutional abbreviations as follows: Division ofFisheries Sciences, Faculty of Agriculture, Miyazaki University, Japan (MUFS), and Raffles Museum of Biodiversity
Research, Department of Biological Sciences, National University of Singapore (ZRC, formerly NMS).

Polynemus melanochir dulcis ssp. nov.
(English name: lake blackhand paradise fish)(Figs. 1, 2)
Holotype. ANSP 178011, 135 mm SL, Tonle Sap Lake, Cambodia,
12 Jan. 1970, collected by O. Okamura.
Paratypes. AMS I. 40968-001, 126 mm SL, BSKU 14850, 128 mm
SL; same data as holotype.

Diagnosis. A subspecies of Polynemus with the following combination of characters: 8 first dorsal-fin spines; 16
soft dorsal-fin rays; 7 pectoral filaments (seventh probably
longest); 16 or 17 (mode 16) pectoral-fin rays; 3 anal-fin

spines; 11 or 12 (12) soft anal-fin rays; 71 or 72 (71) pored
lateral-line scales; 7 scale rows above lateral line, 12 or 13(13) below; 12 gill rakers in upper series, 17–19 (17) in lower,
29–31 (29) total; vomer without teeth; snout long, strongly
pointed (7% of SL); upper caudal-fin lobe short [mean 35%(range 34–35%) of SL]; swimbladder absent.
Description. Counts and proportional measurements of
the holotype and paratypes of Polynemus melanochir dulcis
ssp. nov. are given in Table 1. Data for the holotype arepresented first, followed by paratype data (if different) inparentheses (diagnostic characters not repeated).
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 near midlineof body; posterior tip of pectoral fin not reaching to level ofanal-fin origin (same, or just reaching); first (shortest) andsecond pectoral filaments extending beyond level of pelvicfin origin but not reaching to level of posterior tip of pelvic
fin; third pectoral filament reaching near anal-fin origin;fourth pectoral filament extending slightly beyond levelof middle of anal-fin base (or extending beyond level ofposterior base of anal fin); fifth pectoral filament extending
slightly beyond caudal-fin base (or extending beyond posterior mid-distal margin of caudal fin); sixth and seventh
pectoral filaments extending well beyond posterior tips of
caudal fin (filament tips easily damaged); all bases offirst dorsal-fin spines of similar thickness; lateral line simple,
extending from upper end of gill opening to mid-distal margin of caudal fin membrane; formula for configuration of
supraneural bones, anterior neural spines, and anterior dorsal pterygiophores /0/0⫹2/1/1⫹1/1/1/1/; 10 ⫹ 15 vertebrae.

Fig. 1. Holotype of Polynemus melanochir dulcis ssp. nov., ANSP 178011, 135 mm SL, Tonle Sap Lake, Cambodia

New subspecies and redescription of Polynemus

183

Table 1. Counts and measurements (expressed as percentages of standard length) of Polynemus
melanochir dulcis ssp. nov., including the holotype and paratypes

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 premaxilla
Pre-1st dorsal-fin lengthPre-2nd dorsal-fin lengthPre-anal-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
ANSP 178011

Paratypes
AMS I. 40968-001,
BSKU 14850(n ⫽ 2)135

126–128

VIII-I, 16
III, 12
16
7
I, 5
71
7/13
12 ⫹ 17 ⫽ 29

VIII-I, 16
III, 11–12
16–17
7
I, 5
71–72
7/12–1312 ⫹ 17–19 ⫽ 29–31

27
23
23
16
7
3
3
9
18
14
4
34
59
60
40
27
21
15
31
128
12
17
19
7
19
8
17
27
11
35
34

28 (28)23 (23)23 (23)15 (15)7 (7)3 (3)3–4 (3)
9–8 (8)19 (19)14–15 (14)
3–4 (4)35–36 (35)59–60 (59)59–60 (60)35–38 (38)
26–28 (27)
20–21 (21)15 (15)34–35 (33)153 (141)
13–14 (13)18 (18)
19–20 (19)
8–9 (8)
20–21 (20)
8–9 (8)
18–19 (18)
25–27 (26)
10 (10)34–35 (35)38 (36)Means in parentheses include holotype data

Color of preserved specimens.—Head and body grayishblack dorsally, pale whitish-yellow ventrally; posterior tip offirst dorsal fin intense black, other parts whitish-yellow; posterior margins of second dorsal, pelvic, anal, and caudal finstranslucent (posterior margin of second dorsal fin blackish
in a single specimen, BSKU 14850), anterior margin of second dorsal fin blackish, other parts whitish-yellow; pectoralfin, except posterior tip and base, intense black (translucent

in a single specimen, AMS I. 40968-001); base of pectoral
filaments whitish-yellow, becoming blackish posteriorly.
Distribution. Polynemus melanochir dulcis is currently
known only from Tonle Sap Lake, upper end of the lower
Mekong River floodplain, Cambodia (Fig. 2).
Etymology. The subspecific name “dulcis” is derived
from the Latin meaning “freshwater,” in reference to thetype locality, Tonle Sap Lake.

184

H. Motomura and M.H. Sabaj

Remarks. Polynemus melanochir dulcis clearly differsfrom P. m. melanochir in having a longer snout and shorter
upper caudal-fin lobe (see Discussion). However, with the
exception of certain proportional measurements, the 2forms are difficult to distinguish because their meristic characters fully overlap (see Table 3). Accordingly, P. m. dulcis is
proposed as a new subspecific taxon.

Other material. 39 specimens, 39–194 mm SL. ANSP 114895 (holotype of Trichidion hilleri Fowler, 1905), 166 mm SL, Baram River,
Sarawak, Kalimantan, Malaysia; BMNH 1880.4.21.146, 134 mm SL,
Kalimantan, Indonesia; CAS 132751 (7 specimens), 123–168 mm SL,
Kuching, Sarawak, Kalimantan, Malaysia; FSKU-P 21007–21008 (2),
118–134 mm SL, Tawau, Sabah, Kalimantan, Malaysia; MCZ 16307,
167 mm SL, Calcutta, India (probably erroneous, see Distribution);
MNHN A. 3048 (2 syntypes of Polynemus melanopus Sauvage, 1881),

Polynemus melanochir melanochir Valenciennes
in Cuvier and Valenciennes, 1831
(English name: blackhand paradise fish)(Figs. 2, 3)
Polynemus melanochir Valenciennes in Cuvier and Valenciennes, 1831:
513 [mistakenly reported from India, based solely on a drawing sentfrom Sumatra, Indonesia (see Feltes, 1991, fig. 1); type locality:
Kuching Bay, Sarawak, Kalimantan, Malaysia, based on newly designated neotype; see Article 76.3 (ICZN, 1999) and Discussion].
Polynemus macronema Bleeker, 1852 (not of Pel): 419 (type locality:
Banjarmasin, Pontianak and Sampit, Kalimantan, Indonesia, primaryhomonym of Polynemus macronemus Pel, 1851).
Polynemus borneënsis Bleeker, 1857: 3 [replacement name for P.
macronema Bleeker, but incorrect original spelling; see Article 32.5
(ICZN, 1999)].
Polynemus borneensis Bleeker, 1858: 2 [justified emendation of P.
borneënsis Bleeker; see Article 32.5.2.1 (ICZN, 1999)].
Galeoides microps Steindachner, 1869a: 126 (type locality: China, but
probably erroneous; see Distribution); Steindachner, 1869b (moredetailed description).
Polynemus melanopus Sauvage, 1881: 101 [type locality: Saigon (⫽Hochi-minh), Vietnam].
Trichidion hilleri Fowler, 1905: 502, fig. 11 (type locality: Baram River,
Sarawak, Kalimantan, Malaysia).
Neotype. ZRC 37829, 179 mm SL, Kuching Bay, Sarawak,
Kalimantan, Malaysia, Oct. 1966, trawl.

Fig. 2. Localities of specimens of Polynemus melanochir dulcis ssp. nov.
(star) and P. m. melanochir (circles) examined in this study

Fig. 3. Neotype of Polynemus melanochir melanochir Valenciennes in Cuvier and Valenciennes, 1831, ZRC 37829, 179 mm SL, Kuching Bay,
Sarawak, Kalimantan (⫽Borneo), Malaysia

New subspecies and redescription of Polynemus
139–160 mm SL, Saigon (⫽Ho-chi-minh), Vietnam; MNHN A. 3049 (2syntypes of P. melanopus), 130–160 mm SL, Saigon (⫽Ho-chi-minh),
Vietnam; MUFS 21364–21370 (7), 136–194 mm SL, Mekong Riverat Ho-chi-minh, Vietnam; NMW 77569 (holotype of G. microps
Steindachner, 1869), 171 mm SL, China (specific locality unknown);
RMNH 6013 (3 syntypes of Polynemus borneensis Bleeker, 1857),
148–190 mm SL, Banjarmasin, Pontianak and Sampit, Kalimantan,
Indonesia; RMNH 34138 (formerly RMNH 6013) (2), 80–150 mm SL,
Kahayan and Sinkawang, Kalimantan, Indonesia; UMMZ 213351 (1 of9), 64 mm SL, mouth of Bassac River, 2.5 km southeast of Truong Binh,
Vietnam; UMMZ 213352, 101 mm SL, Long Xuyen, at beginning ofwest branch of Mekong River, Vietnam; UMMZ 217920 (2 of 115),
86 mm SL, My Tho, Mekong River, Vietnam; UMMZ 224614 (3), 39–
75 mm SL, Tho River, Vietnam; UMMZ 225748, 118 mm SL, off mouthof Mekong River, Vietnam; UMMZ 232762, 136 mm SL, Phnom Penh,
Mekong River, Cambodia.

Diagnosis. A subspecies of Polynemus with the following combination of characters: 8 first dorsal-fin spines; 15 or
16 [mode 16, rarely 18 (1 of 40 specimens)] soft dorsal-finrays; 7 pectoral filaments (sixth probably longest); 15–18(mode 17) pectoral-fin rays; 3 anal-fin spines; 11–13 (12) softanal-fin rays; 68–74 (70) pored lateral-line scales; 6–8 (7)scale rows above lateral line, 11–14 (12) below; 11–14 (13)gill rakers in upper series, 16–20 (18) in lower, 27–33 (31)total; vomer without teeth; snout short, blunt [mean 6%(range 5–6%) of SL]; upper caudal-fin lobe long [39% (35–44%) of SL]; swimbladder absent.
Description. Counts and proportional measurementsof the neotype and other material of Polynemus melanochirmelanochir are given in Table 2. Data for the neotype arepresented first, followed by other material data (if different)in parentheses (diagnostic characters not repeated).
Body oblong, compressed; maxilla covered with scales;
lip on lower jaw well-developed; posterior margin of
preopercle slightly serrated (same, or not 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 near midline of body; posterior tip of
pectoral fin just reaching to level of anal-fin origin (same,
not reaching or extending slightly beyond); first pectoral
filament (shortest) extending beyond level of pelvic-fin
origin but not reaching to level of posterior tip of pelvic fin;second pectoral filament extending slightly beyond level ofposterior tip of pelvic fin; third pectoral filament reachingnear anal-fin origin (same, or extending slightly beyond
level of posterior tip of pelvic fin); fourth pectoral filament
extending slightly beyond level of posterior base of anal fin(same, or reaching to base of anal fin); fifth pectoral filament
extending well beyond caudal-fin base, but not reaching
posterior tips of caudal fin (same, or extending slightly
beyond caudal-fin base, not reaching to mid-distal margin of
caudal fin); sixth and seventh pectoral filaments extending
well beyond posterior tips of caudal fin (filament tips easily
damaged); all bases of first dorsal-fin spines of similar thickness; lateral line simple, extending from upper end of gill
opening to mid-distal margin of caudal-fin membrane; formula for configuration of supraneural bones, anterior neural185

spines, and anterior dorsal pterygiophores /0/0⫹2/1/1⫹1/1/
1/1/ (same, or /0/0⫹2/1⫹1/1/1/1/1/); 10 ⫹ 15 vertebrae.
Color when fresh.—Based on MUFS 21369, 154 mm SL,
Mekong River, Vietnam: head and body grayish-black dorsally, yellow ventrally; posterior tip of first dorsal fin intense
black, other parts yellow; posterior margin and tip of second
dorsal fin black, other parts yellow; pelvic fin uniformly
yellow; posterior margins of anal, and caudal fin translucent,other parts yellow; pectoral fin intense black, except forvivid yellow base; base of pectoral filaments vivid yellow,
becoming blackish posteriorly.
Color of preserved specimens.—Head and body grayishblack dorsally, pale whitish-yellow ventrally; posterior tip offirst dorsal fin black, other parts whitish-yellow; posterior
margins of pelvic, anal, and caudal fins translucent, otherparts whitish-yellow; posterior margin of second dorsal fin
blackish or translucent, other parts whitish-yellow; pectoral
fin intense black, except for pale whitish-yellow base; baseof pectoral filaments whitish-yellow, becoming blackish
posteriorly.
Distribution. Polynemus melanochir melanochir is
known from the lower Mekong River and related rivers(Cambodia and southern Vietnam), and Kalimantan(Malaysia and Indonesia), based on specimens examined
during this investigation (see Fig. 2). Data for 2 ofSteindachner’s specimens [MCZ 16307, 167 mm SL, and
NMW 77569 (holotype of Galeoides microps), 171 mm SL],
examined in this study, indicated that they were collectedfrom Calcutta, India (mid-1860s) and China (1869), respectively, but detailed locality and collection date for the specimens were not given. Judging from the presently known
distribution of the species, the former localities are probably
erroneous (omitted from distribution map, Fig. 2).
Valenciennes (in Cuvier and Valenciennes, 1831) solely
based his description of P. melanochir on a fish drawing
sent to London from Sumatra, Indonesia, by Finlayson.
Valenciennes stated that this species existed in India; however, the origin of the illustrated specimen was not specified
on the drawing (reproduced in Feltes, 1991). Recent collections in India and surveys of Indian museums by the seniorauthor failed to find any specimens of P. melanochir fromthe subcontinent. Furthermore, P. melanochir has notbeen known from the neighboring countries of Bangladesh,
Myanmar, and Thailand. It appears that Valenciennes mistakenly presumed that the illustrated specimen originatedfrom India.
Remarks. The
name,
Polynemus
melanochir
Valenciennes in Cuvier and Valenciennes, 1831, has been todate used by many researchers [e.g., Bleeker, 1849; Myers,
1936 (as Filimanus melanochir); Gloerfelt-Tarp and Kailola,1984 (as F. melanochir); Bleeker, 1983 (as Trichidion
melanochir)]. However, Feltes (1991) recognized that thepolynemid species commonly identified as P. melanochir(F. melanochir or T. melanochir) was not true P. melanochir
but in fact represented a separate undescribed species(described as F. perplexa Feltes, 1991). Feltes (1991) andRandall and Lim (2000) correctly identified P. melanochir(⫽P. m. melanochir) but gave no description and no indication of specimens.

Means in parentheses include type data

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 premaxilla
Pre-1st dorsal-fin lengthPre-2nd dorsal-fin lengthPre-anal-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

Standard length (mm)VIII-I, 15–16
III, 12
16–17
7
I, 5
69–70
7/12–13
12–13 ⫹ 18 ⫽ 30–31
24–26
22–24
23–27
13–15
5–6
1–2
2
8–9
17–18
13–15
4
32–34
56–59
56–62
38–40
27–34
19–21
15–16
29–34
Broken
12–13
14–17
15
6–7
16–18
7
16–18
26–28
11–12
39
29

26
25
26
16
6
2
2
9
19
13
4
34
59
61
41
29
19
17
34
157
13
17
Broken
7
19
8
17
26
11
40
35

148–190

Syntypes of
Polynemus borneensis
RMNH 6013(n ⫽ 3)

VIII-I, 16
III, 12
17
7
I, 5
70
7/12
13 ⫹ 19 ⫽ 32

179

Neotype of
Polynemus melanochirmelanochir
ZRC 37829

24
19
21
11
5
2
2
7
17
13
4
33
55
61
35
29
21
15
BrokenBroken
12
15
19
7
17
7
15
27
10
35
32

VIII-I, 16
III, 12
15
7
I, 5
71
—/—
11 ⫹ 16 ⫽ 27

171

Holotype of
Galeoides microps
NMW 77569

25–27
21–24
22–25
12–13
5–6
2
3
8–9
17–19
13–14
4
33–35
56–58
59–61
37–38
28–30
19
14–16
30–31
134–171
12–14
16–17
18–20
7–9
18–20
8
17–18
27–28
10–11
38–40
35–36

VIII-I, 15–16
III, 12
16–17
7
I, 5
69–71
7/12–14
12–13 ⫹ 17–18 ⫽ 30–31

130–160

Syntypes of
Polynemus melanopus
MNHN A. 3049-A. 3050(n ⫽ 4)

27
25
26
15
6
2
2
9
20
14
4
36
59
61
39
29
21
15
32
Broken13
16
19
Broken17
Broken18
28
11
BrokenBrokenVIII-I, 16
III, 12
18
7
I, 5
71
7/14
13 ⫹ 18 ⫽ 31

166

Holotype of
Trichidion hilleri
ANSP 114895

25–27 (26)
22–25 (23)
22–28 (24)
11–16 (14)
5–6 (6)
1–2 (2)
2–3 (2)
7–9 (8)
18–19 (18)
12–14 (13)
3–5 (4)33–35 (33)
57–60 (58)
57–62 (60)
36–40 (38)
26–30 (29)
18–20 (20)
14–17 (16)30–35 (32)
141–193 (159)
12–13 (13)
15–17 (16)
15–20 (18)
7–10 (8)17–21 (19)
7–9 (8)
17–19 (18)
26–29 (27)
10–13 (11)35–44 (39)
33–42 (36)

VIII-I, 15–18
III, 11–13
16–18
7
I, 5
68–74
6–8/11–13
11–14 ⫹ 16–20 ⫽ 28–33

39–194

Non-type specimens of
Polynemus melanochirmelanochir(n ⫽ 30)

Table 2. Counts and measurements (expressed as percentages of standard length) of Polynemus melanochir melanochir, including the neotype, other nominal types, and non-type specimens

186
H. Motomura and M.H. Sabaj

New subspecies and redescription of Polynemus

187

Discussion

Hubrecht (1879) referred to a total of 8 Bleeker specimens
as Trichidion borneënsis (group A, 5 specimens; group B, 1
specimen; group C, 1 specimen; group D, 1 specimen). Five
Bleeker specimens are presently held at RMNH and registered as RMNH 6013 [80 mm SL (112 mm TL), 148 mm SL(ca. 192 mm TL, caudal fin broken), 150 mm SL (207 mm
TL), 162 mm SL (223 mm TL), and 190 mm SL (ca. 247 mm
TL, caudal fin broken)]. Although the caudal fin was damaged in 2 specimens (148 and 190 mm SL), the original total
lengths of these specimens were estimated from the measurements of 31 undamaged specimens (39–194 mm SL) of
P. m. melanochir examined during this study (total length
1.3–1.5 times SL). The estimated total lengths (ca. 192 and247 mm) of these 2 specimens from RMNH 6013 are closest
to those (185 and 245 mm) given by Bleeker (1852); therefore, we recognize these specimens as 2 of the 3 syntypes of
P. borneensis. Of the remaining 3 specimens in RMNH 6013,
the smallest (80 mm SL) can be excluded from the syntypicseries because its total length (112 mm) is outside the rangeof lengths (185–245 mm) given by Bleeker (1852). However,the status (syntype or non-type) of the remaining 2 specimens (207 and 223 mm TL) cannot be determined fromtheir total lengths. Notwithstanding, the larger of these 2
specimens has the body scales marked by green ink stains
along the scale rows of the lateral line and scales below thelateral line. Because it is believed that Bleeker marked thescales with green ink while counting them (M.J.P. van Oijen,
personal communication), it is very likely that the specimen
so marked is the remaining syntype. Therefore, the 2
Bleeker specimens measuring 80 and 150 mm SL are hereinremoved from the syntypes of P. borneensis and reregistered as RMNH 34138.
Polynemus borneensis has been regarded as a valid species by many researchers (e.g., Weber and de Beaufort, 1922;

Although the original description of Polynemus melanochir
Valenciennes in Cuvier and Valenciennes, 1831 was brief,
the drawing clearly shows the very black pectoral fin rays(see Feltes, 1991: fig. 1), such being a characteristic of thespecimens considered here as P. melanochir melanochir. The
specimen used for the drawing apparently no longer exists,
and its precise origin is unknown. The proposal of a neotype
for P. m. melanochir is necessary to avoid taxonomic confusion, owing to the similarity of this species to other congeners, including P. m. dulcis ssp. nov. A specimen (ZRC
37829, 179 mm SL) collected from Kuching Bay, Sarawak,
Kalimantan, Malaysia is herein proposed as the neotype forP. m. melanochir and Kuching Bay becomes the type locality
under Article 76.3 (ICZN, 1999).
Bleeker (1852) described P. macronema as a new species
from Banjarmasin, Pontianak and Sampit, Kalimantan,
Indonesia. Because the name, P. macronema Bleeker, 1852
(primary homonym under Article 57.2, ICZN, 1999), waspreoccupied by P. macronemus of Pel (1851), Bleeker(1857) proposed a replacement name, P. borneënsis, but
used an “incorrect original spelling” as defined by Article
32.5 (ICZN, 1999). Subsequently, Bleeker (1858) corrected
the name to “borneensis,” as a justified emendation (seeArticle 32.5.2.1, ICZN, 1999). Eschmeyer (1998) indicatedthis species as P. borneensis Bleeker, 1860. However, theauthorship and date of P. borneensis is rightly Bleeker(1857), because the corrected name retains the authorshipand date of the original spelling (see Article 33.2.2, ICZN,
1999).
Polynemus borneensis Bleeker, 1857 was described on thebasis of 3 specimens, 185–245 mm TL, used for the originaldescription of P. macronema Bleeker, 1852. Subsequently,

Table 3. Frequency distributions of meristic characters of Polynemus melanochir dulcis ssp. nov. and P. m. melanochir
Soft dorsal-fin rays

P. m. dulcis ssp. nov.
P. m. melanochirn⫽3n ⫽ 40Soft anal-fin rays

15

16

17

18

11

12

13

15

16

17

18

—
10

3a
29b

—
—

—
1

1
2

2a
37b

—
1

—
1

2a
16

1
19b

—
4

Scales above/below lateral line

P. m. dulcis ssp. nov.
P. m. melanochirn⫽3n ⫽ 32c

6

7

8

—
4

3a
27b

—
1

/

Upper gill rakers

P. m. dulcis ssp. nov.
P. m. melanochiran⫽3n ⫽ 38

Pored lateral-line scales

11

12

13

14

68

69

70

71

72

73

74

—
5

1
22b

2a
3

—
2

—
2

—
2

—
11b

2a
9

1
7

—
3

—
1

Lower gill rakers

Total gill rakers

11

12

13

14

16

17

18

19

20

27

28

29

30

31

32

33

—
2

3a
15

—
20b

—
1

—
3

2a
7

—
22

1
5b

—
1

—
1

—
3

2a
4

—
10

1
14

—
5b

—
1

Holotype of P. m. dulcis ssp. nov.
Neotype of P. m. melanochircPored lateral-line scales counted on 35 examples of P. m. melanochirbPectoral-fin rays

188

H. Motomura and M.H. Sabaj

Fig. 5. Relationships of A snout length and B upper caudal-fin lobe
length to standard length in Polynemus melanochir dulcis ssp. nov.
(stars) and P. m. melanochir (circles)

Fig. 4. Heads of A Polynemus melanochir dulcis ssp. nov. and B P. m.
melanochir. A ANSP 178011 (holotype), 135 mm SL, Tonle Sap Lake,
Cambodia; B UMMZ 232762, 136 mm SL, Phnom Penh, Mekong River,Cambodia

Kottelat et al., 1993; Rainboth, 1996). However, our examination of the 3 syntypes of P. borneensis, the neotype of P. m.
melanochir, and other specimens showed that they represented a single species (see Table 2). Accordingly, P.
borneensis is herein regarded as a junior synonym of thelatter.
Galeoides microps was described by Steindachner(1869a) on the basis of a single specimen (NMW 77569,
171 mm SL) from China (probably erroneous, seeDistribution) and later described in more detail(Steindachner, 1869b). Although there is no indication in
the literature that the holotype of G. microps has beenreexamined since Steindachner’s (1869a,b) descriptions(Springer, 1982), the species has been regarded as valid,
belonging to the genus Galeoides (e.g., Fowler, 1935; Myers,
1936; Springer, 1982; Hureau, 1986). Recently, Motomura etal. (2001) examined the holotype of G. microps and regarded it as a junior synonym of P. melanochir (⫽P. m.
melanochir). The meristic and morphological characters of
the holotype of G. microps are herein listed in Table 2 and inMotomura et al. (2001).

Polynemus melanopus was described by Sauvage (1881)
on the basis of 4 specimens (MNHN A. 3048, 2 syntypes,
139–160 mm SL and MNHN A. 3049, 2 syntypes, 130–
160 mm SL) from Saigon (⫽Ho-chi-minh), Vietnam. The
only subsequent reference to the species was by Blanc
and Hureau (1971), who listed it in the type catalogue ofthe Muséum national d’Histoire naturelle. The characters,
black pectoral fin, vomer without teeth, and short snout(5–6% of SL), of the 4 syntypes were found to be consistent
with those of the specimens considered here as P. m.
melanochir (see Table 2). Accordingly, P. melanopus is also
regarded as a junior synonym of the latter.
Trichidion hilleri was described by Fowler (1905) on thebasis of a single specimen (ANSP 114895, 166 mm SL) from
Baram River, Sarawak, Kalimantan, Malaysia. Although thespecies has been regarded as valid (as P. hilleri) by many
researchers (e.g., Kottelat et al., 1993; Kottelat and Lim,
1995), our examination of the holotype of T. hilleri and thespecimens considered here as P. m. melanochir showed thatthey represented a single species (see Table 2). Accordingly,
T. hilleri is also regarded as a junior synonym of the latter.
Polynemus m. dulcis and P. m. melanochir are uniquely
characterized by the absence of vomerine teeth (present inall congeners). Likewise, both subspecies have a very black
pectoral fin. Although the pectoral fin of P. paradiseus
Linnaeus, 1758 is occasionally tinged with black, that species
has villiform vomerine teeth.

New subspecies and redescription of Polynemus

The vomer and pectoral fin characters of P. m. dulcis and
P. m. melanochir are very similar. Furthermore, the meristic
characters of both subspecies completely overlap (Table 3).
However, P. m. dulcis differs from the latter in having agreater snout length [7% of SL vs. mean 6% (range 5–6%)
of SL; Tables 1, 2; Figs. 4, 5] and shorter upper caudal-fin
lobe length [35% (34–35%) of SL vs. 39% (35–44%) of SL;
Tables 1, 2; Fig. 5]. In addition, the head length [mean 28%(27–28%) of SL], dermal eye opening (3% of SL), orbit
diameter [3% (3–4%) of SL], upper-jaw length [14% (14–15%) of SL], second dorsal-fin base length [21% (20–21%)
of SL], and longest pelvic-fin ray length [18% (17–18%) of
SL] in P. m. dulcis are greater than those in P. m. melanochir[26% (24–27%), 2% (1–2%), 2% (2–3%), 13% (12–14%),
20% (18–21%), and 16% (14–17%), respectively; Tables 1,2]. Based on these distinctive characters and the parapatric
distribution of their known populations, the 2 forms aretreated as separate subspecies, P. m. dulcis and P. m.
melanochir.
Acknowledgments We greatly appreciated receiving specimen loans
from the following: M. McGrouther and K. Parkinson (AMS); M.
Littmann and D. Dagit (ANSP); J. Maclaine (BMNH); K. Sasaki and Y.
Machida (BSKU); W.N. Eschmeyer, T. Iwamoto, D. Catania, and J. Fong(CAS); H. Ida and M. Okamoto (FSKU-P); K.E. Hartel (MCZ); M.J.P.
van Oijen, and J. van Egmond (RMNH); D.W. Nelson (UMMZ); andP.K.L. Ng and K.K.P. Lim (ZRC). We are most grateful to E. Mikschi
and H. Wellendorf (NMW) for their provision of holotype data andphotographs of Galeoides microps, M.J.P. van Oijen (RMNH) for providing information on syntypes of Polynemus borneensis, P. Pruvost(MNHN) for the opportunity to examine syntypes of Polynemus
melanopus, and K. Sasaki (BSKU) for providing collection data for
Polynemus melanochir dulcis. We thank Y. Iwatsuki (MUFS) for supporting this study and E. Yamamoto (Fukuoka, Japan) for collecting P.
melanochir from Vietnam. We thank Y. Motomura (Miyazaki, Japan)
for her assistance and G.S. Hardy (Ngunguru, 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).

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