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Schistura callidora, new species, is described from the Myitnge River drainage, Irrawaddy basin (Myanmar). It is distinguished by dark bars on the body much thinner in the anterior half of the body than in the posterior half; a high dorsal crest on the caudal peduncle; 8 1 /2-10 1 /2 branched dorsal-fin rays; and the lateral line reaching behind the base of the anal fin. Pteronemacheilus, new genus, is characterised by the presence of elongated skinfolds on the dorsal side of the second and third branched pectoral-fin rays in males. Pteronemacheilus lucidorsum, new spe-cies, is described from the Myitnge River drainage, Irrawaddy basin (Myanmar). It differs from its only congener, P. meridionalis, by having the dorsal midline without pigmentation and usually 8 + 8 branched caudal-fin rays.
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Ichthyol. Explor. Freshwaters, Vol. 22, No. 1
Ichthyol. Explor. Freshwaters, Vol. 22, No. 1, pp. 1-10, 7 figs., 2 tabs., March 2011
© 2011 by Verlag Dr. Friedrich Pfeil, München, Germany – ISSN 0936-9902
A new genus and two new species of loaches
(Teleostei: Nemacheilidae)
from Myanmar
Jörg Bohlen* and Vendula Šlechtová*
Schistura callidora, new species, is described from the Myitnge River drainage, Irrawaddy basin (Myanmar). It is
distinguished by dark bars on the body much thinner in the anterior half of the body than in the posterior half;
a high dorsal crest on the caudal peduncle; 8 1
/2-10 1
/2 branched dorsal-fin rays; and the lateral line reaching behind
the base of the anal fin. Pteronemacheilus, new genus, is characterised by the presence of elongated skinfolds on
the dorsal side of the second and third branched pectoral-fin rays in males. Pteronemacheilus lucidorsum, new spe-
cies, is described from the Myitnge River drainage, Irrawaddy basin (Myanmar). It differs from its only congener,
P. meridionalis, by having the dorsal midline without pigmentation and usually 8 + 8 branched caudal-fin rays.
* Institut of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Rumburská 89, 277 21
Libechov, Czech Republic. E-mail: bohlen@iapg.cas.cz
Introduction
Loaches of the family Nemacheilidae are a char-
acteristic element of the Eurasian ichthyofauna
and occur in nearly every running water. About
30 genera and 720 nominal species are presently
known, most of them from South and Southeast
Asia. However, there remain a great number of
undescribed taxa in all less sampled mountainous
areas of Southeast Asia. The aim of the present
study is to describe two new species recently
collected in Shan State, Myanmar and to erect a
new genus.
Material and methods
The specimens were either fixed in 4 % formal-
dehyde and later transferred into 70 % ethanol
for storage (all specimens deposited in ZRC and
CMK) or fixed and stored in 96 % ethanol (all
specimens in IAPG). All measurements and
counts follow Kottelat (1990). Measurements were
made point-to-point with digital callipers to the
nearest 0.1 mm. Drawings were done using a
camera lucida on an Olympus SZX7 stereomicro-
scope. Collection abbreviations: CMK, Collection
of Maurice Kottelat, Cornol; IAPG, Institute of
Animal Physiology and Genetics, Laboratory of
Fish Genetics, Libechov; ZRC, Zoological Refer-
ence Collection, Raffles Museum of Biodiversity
Research, Department of Biological Sciences,
National University of Singapore, Singapore.
2
Bohlen & Šlechtová: New loaches from Myanmar
Schistura callidora, new species
(Figs. 1-2)
Holotype. ZRC 52037, 40.7 mm SL; Myanmar:
Shan State: mouth of Nam Paw at confluence with
Myitnge River at Hsipaw city, 22°37'24" N 97°18'
12" E; R. Hoyer, 25 Nov 2009.
Paratypes. ZRC 52038, 4, 35.8-41.5 mm SL; IAPG
A3909-3910, 2, 32.2-36.3 mm SL; CMK 21899, 1,
37.2 mm SL; same data as holotype.
Diagnosis. Schistura callidora is distinguished
from all other species of Schistura by the combina-
tion of the following characters: a prominent skin
crest on the dorsal midline of the caudal pedun-
cle (skin crest 15-19 % of caudal peduncle depth),
but no skin crest on the ventral midline of the
caudal peduncle; 8
1
/
2-10 1
/
2 branched dorsal-fin
rays; caudal fin deeply forked; 12-17 vertical bars
on the flank, thin and densely set between oper-
cle and dorsal-fin origin but broad and widely
set under and behind base of dorsal fin.
Description. See Figures 1 and 2 for general ap-
pearance and Table 1 for morphometric data of
holotype and 7 paratypes. A relatively small
nemacheilid loach with moderately elongated
body. Body anteriorly slightly compressed, caudal
peduncle compressed. Maximum body depth
between pectoral-fin base and dorsal-fin origin.
Width of head constantly increasing from level
of mouth backwards. Depth of caudal peduncle
0.8-1.0 times in its length. Axillary pelvic lobe
present and free. A pronounced adipose crest on
dorsal midline of caudal peduncle between dor-
sal and caudal-fin bases; its height 15-19 % of
depth of caudal peduncle. No adipose crest on
ventral midline of caudal peduncle or restricted
to stretch between end of last dark body bar and
caudal-fin base. Largest known size 41.5 mm
SL.
Dorsal fin with 4 simple and 8 1
/
2-10 1
/
2 branched
rays. Distal margin of dorsal fin straight. Anal fin
with 3 simple and 5 1
/
2 branched rays, not reaching
caudal-fin base. Caudal fin with 9 + 8 branched
rays, deeply forked, lobes pointed. Pelvic fin with
8 rays; origin under branched dorsal-fin ray 2-3;
reaching slightly beyond half of distance to anal-
fin origin; not reaching anus, which is situated
about one eye diameter in front of anal fin. Pec-
toral fin with 10 or 11 rays, reaching slightly
behind half of distance between bases of pectoral
and pelvic fins.
No scales on body in front of dorsal fin; few
scales on flank below dorsal-fin base, arranged
mainly along lateral line; body completely covered
by scales (except belly) behind dorsal-fin base.
Lateral line reaching behind base of anal fin, with
75-81 pores. Cephalic lateral line system with 6
supraorbital, 4 + 10 infraorbital, 9 pre-operculo-
mandibular and 3 supratemporal pores. Lips and
barbels covered with unculi.
Anterior nostril pierced in front side of a flap-
like tube, with a low anterior rim. Mouth gape
about three times wider than long (Fig. 3). Proces-
sus dentiformis wide, low, broadly rounded. Lips
thick; upper lip with a well-marked median inci-
sion and no furrows. Lower lip with a broad
median interruption and on each side 3-5 furrows.
Inner rostral barbel reaching corner of mouth,
outer one reaching behind base of maxillary
barbel, maxillary barbel reaching behind vertical
through posterior rim of eye.
Fig. 1. Schistura callidora, ZRC 52037, holotype, 40.7 mm SL; Myanmar: Shan State: Hsipaw. Alive, shortly after
capture. Right side, reversed. Photo R. Hoyer.
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Ichthyol. Explor. Freshwaters, Vol. 22, No. 1
Fig. 2. Schistura callidora, Myanmar: Shan State: Hsipaw. a, ZRC 52037, holotype, 40.7 mm SL; b, ZRC 52038,
paratype, 41.5 mm SL; c, ZRC 52038, paratype, 36.5 mm SL, with aberrant colour pattern.
a
b
c
Sexual dimorphism. None observed.
Colouration. Ground colour in freshly preserved
specimens yellowish. Head except ventral side
with regularly spread pigment cells. Areas of
higher density of pigment cells form an irregular
dark grey blotch before neck, a triangular blotch
between eyes, half rings around dorsal base of
nostrils and an irregular stripe from snout to
ventral margin of nare; upper lip and base of
rostral barbel with scattered black pigment cells.
Body with 12-17 dark brown bars reaching ven-
trally to level of pectoral-fin base. Six to 11 of
them between opercle and dorsal-fin origin, ir-
regular, about width of interspaces; occasionally
neighbouring bars are connected at their dorsal
extremity. Pre-dorsal bars not reaching dorsal
midline; instead, two dorsal saddles between nape
and dorsal-fin origin, reaching laterally down to
dorsal end of lateral bars. Five or 6 bars under
and behind base of dorsal fin usually more than
twice width of predorsal bars and slightly broad-
4
er than interspaces; reaching ventrally at least to
level of pelvic fin and dorsally to dorsal midline,
where in most cases bars from opposite body
sides meet. Margins of posterior bars darker than
median area. Black bar at base of caudal fin thin,
continuous; usually reaching dorsal midline but
not ventral midline. Three black blotches at base
of dorsal fin, stretching across last unbranched
and first branched ray; third to fifth or sixth
branched rays and on last two branched rays,
respectively. Two to three rows of black spots on
dorsal fin, situated on rays, membrane hyaline.
Caudal fin with a single row of dots, forming a
V-shaped band; faint in some specimens; always
most conspicuously marked on median rays.
Other fins without pigment.
One paratype with different colouration: 6
predorsal bars and 3 saddles between nape and
dorsal-fin origin. Each saddle joined with two
lateral bands on each side. All bars much wider
than interspaces, black bar at base of caudal fin
of double width than in other specimens and no
dark dots on fins.
Habitat. All specimens of S. callidora were col-
lected at the mouth of a stream up to 20 m wide.
The substrate in the creek was a mixture of
gravel, stones and boulders of up to 30 cm diam-
Table 1. Morphometric data of holotype and 7 paratypes of Schistura callidora.
holotype range mean S.D.
Standard length (mm) 40.7 32.2-41.5
In percent of standard length
Total length 123.8 122.5-126.4 124.5 1.1
Dorsal head length 20.1 19.6-22.4 21.1 1.0
Lateral head length 21.4 21.4-24.1 23.0 1.0
Predorsal length 49.4 47.7-51.2 49.8 1.3
Pre-pelvic length 51.1 51.1-53.7 52.5 0.9
Pre-anus length 73.5 69.4-73.5 72.1 1.5
Preanal length 77.6 75.1-79.5 77.5 1.4
Head depth at eye 12.0 11.3-12.4 12.0 0.4
Head depth at nape 13.5 13.5-15.2 14.4 0.7
Body depth 18.4 17.5-19.9 19.0 0.8
Depth of caudal peduncle 15.0 14.4-16.1 15.2 0.6
Length of caudal peduncle 13.5 12.7-14.5 13.5 0.6
Snout length 9.6 9.1-10.3 9.5 0.4
Head width at nares 8.6 8.4-9.5 8.7 0.4
Maximum head width 16.0 14.8-16.4 15.6 0.5
Body width at dorsal-fin origin 13.5 12.6-14.5 13.6 0.7
Body width at anal-fin origin 6.6 6.0-7.5 6.6 0.5
Eye diameter 4.9 4.9-5.9 5.3 0.4
Interorbital width 6.1 5.8-6.8 6.3 0.3
Height of dorsal fin 14.3 14.1-18.2 15.8 1.5
Length of upper caudal lobe 23.3 21.6-25.2 23.1 1.1
Length of median caudal ray 15.0 13.3-16.1 14.7 0.9
Length of lower caudal lobe 23.3 21.6-25.5 23.6 1.3
Depth of anal fin 18.2 17.0-18.6 17.8 0.7
Length of pelvic fin 18.2 17.8-19.5 18.7 0.6
Length of pectoral fin 21.9 20.5-24.0 22.6 1.1
Fig. 3. Schistura callidora, ZRC 52037, holotype, 40.7 mm
SL; mouth. Scale bar 1 mm.
Bohlen & Šlechtová: New loaches from Myanmar
5
Ichthyol. Explor. Freshwaters, Vol. 22, No. 1
eter with few larger stones. Maximum water depth
was 50 cm. At the time of sampling the water was
clear and had a temperature of 24.4 °C (air tem-
perature 23.2 °C), a conductivity of 2.6 S · m1 and
a pH 6.5.
Distribution. Schistura callidora is presently
known only from the Myit Nge River drainage
in the surrounding of the city Hsipaw.
Etymology. The name callidora is derived from
the Greek words calloni, beauty, and doro, gift,
meaning gifted with beauty. Treated as a noun
in apposition.
Remarks. Schistura callidora belongs to a group
of species with a conspicuous adipose crest on
the dorsal midline of the caudal peduncle and
9 1
/
2 branched dorsal-fin rays (vs. no or low adipose
crest and 7
1
/
2 or 8
1
/
2 in most other species of
Schistura) (Zhou & Kottelat, 2005). This group
includes S. alticrista and S. disparizona. Schistura
callidora also shares with S. alticrista and S. dispari-
zona the absence of a suborbital flap and modified
pectoral fin rays as sexual dimorphism, the pres-
ence of an axillary lobe and the continuous black
bar at the base of the caudal fin. Schistura calli dora
differs from S. alticrista by the colour pattern
consisting of narrow, densely set bars in the an-
terior part of flank and broader bars and inter-
spaces in the posterior area (vs. bars and inter-
spaces equally wide on whole body), by the ab-
sence of a conspicuous adipose crest on the
ventral midline of the caudal peduncle (vs. pres-
ence), by the prominent incision in upper lip (vs.
small incision) and by the forked caudal fin (vs.
emarginated). Schistura alticrista is known from
the Salween basin in Thailand (and is expected
to be also present in Myanmar), while S. callidora
occurs in the Irrawady basin in Myanmar.
Schistura callidora shares with S. disparizona
the general colour pattern, but differs from it by
the absence of a conspicuous adipose crest on the
ventral midline of the caudal peduncle (vs. pres-
ence), by having a deeper caudal peduncle (depth
0.8-1.0 times in its length, vs. 0.9-1.4), dark grey
or black blotches or dots on the top of the head
and on the dorsal and caudal fins (vs. absence),
the anterior bars as wide or wider than the inter-
spaces (vs. much thinner), the black bar at the
basis of the caudal fin reaching the dorsal midline
(vs. not reaching) and usually two predorsal sad-
dles (vs 3-5). Schistura disparizona is known only
from the Salween basin in China, while S. calli dora
occurs in the Irrawady basin in Myanmar.
Schistura callidora shows a greater variability
in the number of branched dorsal-fin rays than
S. alticrista and S. disparizona (8 1
/
2 to 10 1
/
2 vs. 9 1
/
2)
and in number of rows of small dots in dorsal fin
(one to three vs. one). One of the paratypes of
S. callidora differs from the other specimens in
having all body bars broader than the inter-
spaces (vs. about the same width in all other
specimens), three saddles between nape and
dorsal-fin origin (vs. two), posterior bars homo-
genously pigmented (vs. the margins darker than
the centre) and round tips of lobel of caudal fin
(vs. pointed). After a careful comparison of the
specimen with the other specimens we come to
the conclusion that they are conspecific and con-
sider the differences as intraspecific variability.
Pteronemacheilus, new genus
Type species. Pteronemacheilus lucidorsum, new
species.
Diagnosis. Pteronemacheilus is distinguished from
all other genera of Nemacheilidae by the presence
of elongated skinfolds on the dorsal side of the
second and third branched pectoral-fin rays in
males. Species-level apomorphic features are
presented in the species diagnosis.
Etymology. The generic name is derived from
the Greek word ptero, wing, used as prefix here,
and the generic name Nemacheilus, the type genus
of the family Nemacheilidae; meaning nemachei-
lid loach with wings, referring to the skinfolds
on the pectoral fins of males. Gender mascu-
line.
Remarks. Male characters of sexually dimorphic
Nemacheilidae comprise thickened pectoral fin
rays (e. g. Barbatula, Neonoemacheilus), prolonged
pectoral and pelvic fins (e. g. Physoschistura), a
suborbital flap (e. g. Acanthocobitis, Nemacheilus,
Schistura) or suborbital groove (Acanthocobitis)
under the eye, tubercles on the pectoral fin and
head (e. g. Barbatula, Triplophysa) and different
head shape (Triplophysa). Only two species of
Nemacheilidae are know to bear skinfolds on the
pectoral fins in males: Pteronemacheilus lucidorsum
and Nemachilus meridionalis Zhu, 1982. Nemachi lus
meridionalis was considered as member of Schist-
6
ura by Zhu (1989, 1995) and of Physoschistura by
Kottelat (2001). N. meridionalis differs from all
three genera by the skinfolds on the pectoral fins
in adult males. Unpublished genetic data show
that P. lucidorsum and N. meridionalis are closely
related to each other but not to the type species
of Schistura (S. rupecola) or of Physoschistura
(P. brunneana). We consider that N. meridionalis
belongs to Pteronemacheilus.
The presence of male-specific structures on
the pectoral fins is a common character in spined
loaches, family Cobitidae, occurs in some genera
of the family Balitoridae (e. g. Sewellia) and in
Pteronemacheilus of the family Nemacheilidae. The
occurrence of structures in the same position in
phylogenetically distinct lineages suggests that
sexual dimorphism in the pectoral fin is a plesio-
morph character of loaches in general.
Pteronemacheilus lucidorsum, new species
(Figs. 4-5)
Holotype. ZRC 52039, 41.2 mm SL, male; Myan-
mar: Shan State: stream Nam Paw west of Hsipaw
city; 22°37'37" N 97°17'19" E; R. Hoyer, 24 Nov
2009.
Paratypes. ZRC 52040, 26, 27.8-53.0 mm SL;
IAPG A3911-3915, 5, 32.4-40.3 mm SL; CMK
21900, 6, 35.2-44.6 mm SL; same data as holo-
type.
Diagnosis. Pteronemacheilus lucidorsum differs
from all other species of the family Nemacheilidae,
except its only congener P. meridionalis, by the
presence of elongated skinfolds on the dorsal side
of the second and third branched pectoral-fin rays
in males. It differs from P. meridionalis by having
the dorsal midline without pigmentation (vs. bars
or saddles across dorsal midline) and usually 8 + 8
branched caudal-fin rays (vs. 9 + 8).
Description. See Figures 4 and 5 for general ap-
pearance and Table 2 for morphometric data of
holotype and 20 paratypes. A relatively small
nemacheilid loach with moderately elongated
body. Body anteriorly only very slightly com-
pressed, caudal peduncle compressed. Maximum
body depth between pectoral-fin base and dorsal-
fin origin. Head width constantly increasing
until end of opercle. Depth of caudal peduncle
0.9-1.0 times in its length. Anus situated about
one eye diameter in front of anal fin. Axillary
pelvic lobe present and free. No adipose crest on
dorsal or ventral midline of caudal peduncle.
Largest known size 53.0 mm SL.
Dorsal fin with 4 simple and 7
1
/
2 or 8
1
/
2
branched rays. Distal margin of dorsal fin straight
or slightly convex. Anal fin with 3 simple and 5 1
/
2
branched rays, nearly reaching caudal-fin base.
Caudal fin usually with 8 + 8, rarely with 9 + 8
branched rays, deeply emarginated, lobes round-
ed. Pelvic fins with 8 rays; origin under branched
dorsal-fin ray 2-3; not reaching beyond anus.
Pectoral fin with 11, rarely 12 rays, reaching
nearly to base of pelvic fin.
Body completely covered with scales except
belly in front of anal-fin origin. Lateral line reach-
ing to anal-fin origin; with 63-75 pores. Cephalic
lateral line system with 6 supraorbital, 4 + 10 in-
fraorbital, 9 pre-operculo-mandibular and 3 su-
pratemporal pores. Lips and barbels covered with
unculi.
Fig. 4. Pteronemacheilus lucidorsum, not preserved; about 38 mm SL; Myanmar: Shan State: stream Nam Paw west
of Hsipaw. Photo R. Hoyer.
Bohlen & Šlechtová: New loaches from Myanmar
7
Ichthyol. Explor. Freshwaters, Vol. 22, No. 1
a
b
c
e
gd
f
h
Fig. 5. Pteronemacheilus lucidorsum, Myanmar: Shan State: Nam Paw stream. a-b, ZRC 52039, holotype, 41.2 mm
SL; c-h, ZRC 52040, paratypes, females (c-e), 36.4-46.6 mm SL, males (f-h), 32.6-38.8 mm SL.
Anterior nostril pierced in front side of a flap-
like tube, with a low anterior rim. Mouth gape
about three times wider than long (Fig. 6a). Proc-
essus dentiformis wide, low, broadly rounded.
Lips thick; upper lip with a well-marked median
incision and small furrows on its whole length.
Lower lip with a broad median interruption and
on each side a prominent pad with 3-5 furrows.
Inner rostral barbel reaching corner of mouth,
outer one reaching behind base of maxillary
barbel and beyond vertical through anterior rim
of eye, maxillary barbel reaching behind vertical
through posterior rim of eye.
8
Sexual dimorphism. Males with an elongated
skinfold on dorsal side of second and third
branched pectoral-fin rays (Fig. 6b). No suborbital
flap present in males and no sexual dimorphism
observed in pigmentation pattern, size, and fin
length.
Colouration. Ground colour in freshly preserved
specimens white to yellowish, lighter on ventral
side, darker on dorsal side. Head except ventral
side with dark grey or brown vermiculate pattern.
In some specimens a faint dark grey stripe from
base of rostral barbel to margin of eye; upper lip
and rostral barbels with black pigment cells of
varying density. Black dot on lateral base of
maxillary barbel. Flank in most specimens with
dark brown bars reaching ventrally to level of
pectoral-fin base, but in some specimens with fine
mottled or vermiculate pattern. Pattern on body
sides varying substantially between individuals
and no two specimens showing same pattern. In
some specimens, a faint black stripe with indis-
tinct outline present along lateral midline. No
pigmentation pattern element along dorsal mid-
line except a single brown dot at origin of dorsal
fin, surrounding base of unbranched and first
branched rays. Most specimens with two black
dots at base of caudal fin; upper one at margin
of caudal-fin base, smaller than eye, black and
with distinct outline; lower one about 1-2 times
size of eye, but less dark than upper one and
often with unsharp outline. Two to three rows of
black spots in dorsal fin, on rays, membranes
hyaline; caudal fin with three to four irregular
rows of black spots on rays, membranes hyaline.
All other fins regularly with pigments at half
length of fin rays, sometimes forming an unclear
band.
Habitat. The Nam Paw is a fast flowing stream
about 4-10 m wide (Fig. 7) and 0.5 m deep at time
of sampling (late dry season), but according to
size of stones in the stream, water volume might
be much higher during rainy season. The bottom
Table 2. Morphometric data of holotype and 20 paratypes of Pteronemaceilus lucidorsum.
holotype range mean S.D.
Standard length (mm) 41.7 33.2-53.0
In percent of standard length
Total length 122.8 121.6-127.2 124.7 1.4
Dorsal head length 20.4 17.8-22.2 20.2 1.1
Lateral head length 23.0 21.7-24.5 22.8 0.8
Predorsal length 48.9 49.1-53.6 51.2 1.3
Pre-pelvic length 50.6 51.2-55.1 53.0 1.1
Pre-anus length 68.6 70.3-75.3 72.9 1.3
Preanal length 76.0 76.0-80.5 78.7 1.3
Head depth at eye 11.0 10.4-13.2 11.6 0.6
Head depth at nape 13.9 13.1-16.5 14.4 0.8
Body depth 19.2 16.9-21.3 19.6 1.1
Depth of caudal peduncle 14.1 13.0-15.8 14.1 0.9
Length of caudal peduncle 13.4 12.2-14.6 13.7 0.7
Snout length 8.6 7.2-9.8 8.7 0.6
Head width at nares 9.8 8.1-11.4 9.9 0.8
Maximum head width 15.6 14.4-18.1 16.2 0.8
Body width at dorsal origin 13.7 13.2-17.7 15.1 1.2
Body width at anal origin 7.7 7.6-10.3 8.7 0.8
Eye diameter 4.6 4.0-5.3 4.6 0.4
Interorbital width 7.2 6.5-8.4 7.2 0.5
Height of dorsal fin 14.9 13.5-16.8 15.2 1.0
Length of upper caudal lobe 21.6 21.4-25.8 23.3 1.2
Length of median caudal ray 18.5 16.8-22.5 19.5 1.5
Length of lower caudal lobe 22.5 21.6-26.3 23.8 1.1
Depth of anal fin 19.4 17.6-20.8 19.2 1.0
Length of pelvic fin 19.4 17.5-21.0 19.6 0.8
Length of pectoral fin 22.5 18.8-25.1 22.1 1.5
Bohlen & Šlechtová: New loaches from Myanmar
9
Ichthyol. Explor. Freshwaters, Vol. 22, No. 1
consists mainly of stones up to 60 cm diameter.
At the time of sampling the water was clear and
the temperature was 24.4 °C (air temperature
23.2 °C), the conductivity 2.6 S · m1 and pH 6.5.
Among other fish species collected with P. luci-
dorsum were two other loach species: Lepido-
cephalichthys berdmorei (Cobitidae) and a single
specimen of Physoschistura raoi (Nemacheilidae).
Distribution. Pteronemacheilus lucidorsum is pres-
ently known only from the Nam Paw at Hsipaw,
Myanmar.
Etymology. The name is derived from the Latin
words lux, light, and dorsum, back, meaning with
a light back, referring to the absence of pigmen-
tation along the dorsal midline. A noun in ap-
position.
Remarks. Using the key in Kottelat (1990), the
new species was identified as a member of the
genus Physoschistura by the strongly arched mouth
and by the median interruption in the lower lip
with broad pads on either side. However, it differs
from Physoschistura and all other Nemacheilidae
except its only congener P. meridionalis by the
presence of an elongated skinfold on the dorsal
side of the second and third branched pectoral-fin
rays in males. It differs from P. meridionalis by
having the dorsal midline without pigmentation
(vs. with bands or saddles) and by having usu-
ally 8 + 8 branched caudal-fin rays (vs. 9 + 8). It
further differs from P. meridionalis by the variable
lateral pigmentation; the pigmentation can be
banded, mottled or a combination of both; no two
specimens have the same pigmentation and dif-
ferent pigmentation patterns are not sex-related
(vs. body with about 15-25 irregular bars, males
tend to have a midlongitudinal black stripe).
Comparative material. Schistura alticrista: IAPG uncat.,
1; Thailand: Mae Hong Son Prov.: Mae La Ka.
Schistura disparizona: CMK 18395, paratypes, 2;
China: Yunnan Prov.: Nangun River (available as high-
resolution photographs).
Pteronemacheilus meridionalis: IAPG A2982-2983, 2;
China: Yunnan Prov.: Man Pa River. – IAPG A3132-
3141, 10; China: Yunnan Prov.: unnamed creek flowing
to Salween River. – IAPG A3101, 1; China: Yunnan
Prov.: Man Pa River. – CMK 14321, 7; Laos: Louang
Namtha Prov.: Nam Youan watershed. – CMK 5635, 2;
China: Yunnan Prov.: Mekong watershed around
Mengla.
Physoschistura raoi: IAPG uncat., 1; Myanmar: Shan
state: Nam Paw.
Physoschistura brunneana: IAPG uncat., 4; Myanmar:
Shan state: Lake Inle.
Physoschistura pseudobrunneana: IAPG uncat., 10;
Thailand: Chiang Mai Prov.: Mae Nam Lao. – IAPG
uncat., 1; Thailand: Chiang Mai Prov.: Mae Nam Yom.
Acknowledgements
We are grateful to Rainer Hoyer for the specimens of
the new species and photographs of live specimens and
habitat. Maurice Kottelat kindly made photographs of
paratypes of S. disparizona available to us. This study
was supported by grants 206/08/0637 and 206/05/2556
of the Czech Science Foundation, No A600450508 of the
Grant Agency of the Academy of Sciences of the Czech
Republic and by the IRP IAPG No. AV0Z50450515.
Fig. 6. Pteronemacheilus lucidorsum, ZRC 52039, holotype, 41.2 mm SL; a, mouth; b, right pectoral fin showing
elongated skinfold on dorsal side of second and third branched rays. Scale bars 1 mm.
a b
10
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Bohlen & Šlechtová: New loaches from Myanmar
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Schistura disparizona, new species, is described from Nangun River (a tributary of the Salween) in Yunnan, China. It is distinguished by conspicuous dorsal and ventral adipose keels on caudal peduncle, 9(1)/(2) branched dorsal-fin rays; 8-11 very narrow, closely-set, dark bars in anterior part of body and 5 wider bars posteriorly.
Myanmar: stream Nam Paw at Hsipaw, type locality of Pteronemacheilus lucidorsum; looking upstreams and to the west
  • Fig
Fig. 7. Myanmar: stream Nam Paw at Hsipaw, type locality of Pteronemacheilus lucidorsum; looking upstreams and to the west. Photo R. Hoyer.
[The loaches of the subfamily Nemacheilinae in China (Cypriniformes: Cobitidae)]. Jiangsu Science and Technology Publishing House
  • S.-Q Zhu
Zhu, S.-Q. 1989. [The loaches of the subfamily Nemacheilinae in China (Cypriniformes: Cobitidae)]. Jiangsu Science and Technology Publishing House, Nanjing, 150 pp. [In Chinese].