Zootaxa 2164: 41–48 (2009)
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Copyright © 2009 · Magnolia Press
ZOOTAXA
ISSN 1175-5334 (online edition)
Danio aesculapii, a new species of danio from south-western Myanmar
(Teleostei: Cyprinidae)
SVEN O. KULLANDER & FANG FANG
Department of Vertebrate Zoology, Swedish Museum of Natural History, PO Box 50007, SE-104 05 Stockholm, Sweden. E-mail:
sven.kullander@nrm.se; fang.kullander@nrm.se
Abstract
Danio aesculapii, new species, is described from small rivers on the western slope of the Rakhine Yoma in south-western
Myanmar. It is superficially similar to D. choprae from northern Myanmar in having a series of vertical bars anteriorly
on the side, but differs from it and other species of Danio in having six instead of seven or more branched dorsal-fin rays,
and from all other species of Danio except D. erythromicron and D. kerri in having 12 instead of 10 or 14
circumpeduncular scale rows.
Key words: Rakhine Yoma, Thandwe, Danio choprae, endemism
Introduction
The cyprinid fish genus Danio Hamilton includes 14 small species in South and Southeast Asia (Kullander et
al. 2009), as a rule diagnosable by distinct species-specific colour patterns. About half of the species of Danio
have a pigment pattern that consists of one or more dark or light horizontal stripes (Fang, 1998). Among the
others, Danio kyathit Fang differs in having the stripes broken up into rows of small brown spots, D.
margaritatus (Roberts) has a pattern of small light spots on the sides, D. dangila (Hamilton) has rows of dark
rings with light centres, and D. choprae Hora and D. erythromicron (Annandale) possess a distinct pattern of
vertical bars.
Danio choprae was described by Hora (1928) from near Myitkyina in the upper Ayeyarwaddy River
drainage, and noted to have a very characteristic colour pattern, including several dark vertical bars anteriorly
on the side. Later, Hora (1937) reported another four specimens, this time in a collection made in Sandoway,
located on the west coast of Myanmar, in the Rakhine State and presently known as Thandwe. Hora’s (1937)
identification appears to have been focused on the vertical bars, and he noticed differences in other colour
marks and lateral line development from the type series of D. choprae. Collections from near Thandwe made
in 1998 included many specimens of a very small species with a diffuse pattern of vertical bars, similar to D.
choprae, and agreeing with the figure of D. choprae reported by Hora (1937: fig 2) from Thandwe (Fig. 1). In
the meantime, this species was also imported to Europe as aquarium fish with the code names “pantheri”,
“snakeskin”, and “TW03”, and further collected to the north and south of Thandwe. This paper is dedicated to
the formal description of this species.
Material and methods
Specimens were fixed in formalin in the field, eventually transferred to 70 % ethanol for storage, and are kept
in the fish collection of the Swedish Museum of Natural History, Stockholm (NRM) or the Natural History
Accepted by R. Pethiyagoda: 27 Jun. 2009; published: 21 Jul. 2009
41
Museum, London (BMNH). Comparative material is also preserved in the Museum of Zoology, University of
Michigan, Ann Arbor, USA (UMMZ). Measurements were taken with digital calipers to a precision of 0.1
mm. Counts and measurements were made according to Fang (1997), and colour pattern terminology follows
Fang (1998). Horizontal stripes are identified by alphanumeric annotations: the P stripe is the dark stripe
along the middle of the side, those above are numbered P+1, P+2, those below P-1, P-2, P-3; stripes on the
anal fin are numbered with the middle one the A stripe, the proximal stripe A+1, and the distal stripe A-1. A
submarginal dark stripe in the dorsal fin is termed D stripe. Fin-ray counts from median fins and vertebral
counts were obtained from X-radiographs made with a Philips MG-105 low voltage X-ray unit and Kodax XOmat V plates. Abdominal vertebrae counts include the Weberian apparatus (assumed to contain four centra).
Statistics were calculated using SPSS v. 17 (SPSS, 2008).
Comparative material. Danio albolineatus (Blyth), NRM 37308; D. choprae, NRM 52001; D. dangila,
NRM 51441; D. erythromicron, NRM 51629; D. feegradei Hora, NRM 55111; D. kerri Smith, NRM 36414;
D. kyathit, NRM 50496; D. margaritatus, NRM 55113; D. meghalayensis Sen & Dey, UMMZ 243666; D.
nigrofasciatus (Day), NRM 37250; D. rerio (Hamilton), NRM 40446; D. roseus Fang & Kottelat, NRM
44799.
FIGURE 1. Danio aesculapii, drawing from Hora (1937: fig. 2), based on a 33 mm TL specimen from Thandwe.
FIGURE 2. Danio aesculapii, holotype, NRM 44490, male, 22.5 mm SL; Myanmar: Rakhine State: Thandwe:
Kananmae Chaung, near Leldee village.
Danio aesculapii, new species
(Fig. 2)
Holotype. NRM 44490, 22.5 mm SL; Myanmar: Rakhine State: Thandwe: Kananmae Chaung, near Leldee
village, by foot 45 min from Gwechaung village at km 18 on road Thandwe–Taunggok, 18°35'39''N
94°22'45''E; 20 Mar 1998, S.O. Kullander & R. Britz (SOK-98-007).
Paratypes. All from Myanmar, Rakhine State. NRM 40826, 31, 14.7–22.3 mm SL; same data as
holotype. — NRM 40804, 38, 17.1–23.7 mm SL; Thandwe: Kamyit Chaung near Paukdu village, 18°15'57''N
94°30'03''E; 19 Mar 1998, S.O. Kullander & R. Britz (SOK-98-005). — NRM 40812, 78, 15.7–21.3 mm SL;
NRM 41269, 5, 17.7–24.4 mm SL; NRM 44907, 19, 19.0–21.1 mm SL; NRM 45662, 1, 22.1 mm SL;
Thandwe: Thandwe River drainage: Nan Chaung, a stream at 3 km on road from Thandwe (market) to
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KULLANDER & FANG
Ngapali, 18°27'08''N 94°20'55''E; 20 Mar 1998, S.O. Kullander & R. Britz (SOK-98-006). — NRM 40851, 3,
18.6–21.7 mm SL; Thade River drainage: Taunggok, Yan Khaw Chaung, ca 4 km on logging road from
Gwetauk village, 23 km on road Taunggok–Pyay, 18°47'48"N 94°21'46"E; 21 Mar 1998, S.O.Kullander & R.
Britz (SOK-98-010). — BMNH 2009.5.5.19. 1, 22.7 mm SL; Kaladan River delta: Chaung Gyi bridge in
Myay Pon township, 20°08'05''N 93°27'06''E; 1 Apr 2007, R. Britz & J. Maclaine. — BMNH 2009.5.5.1–18,
18, 23.4–28.6 mm SL; Kyeintali River drainage: Kyeintali Chaung; Mar 2006, U Tin Win et al.
Non-types. NRM 52338, 1, 29.6 mm SL; NRM 52341, 25.9 mm SL; Aquarium import; 16 Aug 2005, M.
Håkansson. — NRM 52539, 1, 26.0 mm SL; NRM 52542, 24.4 mm SL; Aquarium import; 9 Nov 2005.
Diagnosis. Different from all other species of Danio by colour pattern comprising 6–7 brown vertical bars
anteriorly on side and two horizontal rows of small brown spots posteriorly, absence of D stripe, and absence
of dark stripes on caudal fin; similar to D. kerri and D. erythromicron in possession of 12 circumpeduncular
scale rows vs. 14 in D. dangila and 10 in other species of Danio; by possession of 6 branched dorsal fin rays,
vs. 7–8 in other species of Danio.
Description. Measurements and counts were taken from ten specimens, 20.0–22.5 mm SL (Table 1),
supplemented by counts from additional X-radiographed specimens. The holotype is well preserved but most
other specimens have lost scales. General body features and pigmentation are illustrated in Figs. 1–2. External
sexual dimorphism restricted to slightly rounder abdomen and slightly less developed tubercle field on lower
jaw in females,.
Body compressed, elongate. Head compressed, slightly deeper than wide. Snout short, rounded, shorter
than eye diameter. Mouth terminal, obliquely directed upwards. Small bony knob at dentary symphysis.
Maxilla reaching to below anterior margin of orbit; premaxillary ascending processes not reaching to vertical
from anterior margin of orbit. Lower jaw projecting slightly beyond upper jaw, ending anteriorly at horizontal
through middle of eye. Lower jaw with anterior fleshy lateral lobe beset with small conical tubercles;
anteriorly on lower jaw several conical tubercles; a row of conical tubercles along lateral margin of dentary
posterior to lateral lobe. Tuberculation variably developed, stronger in males. Maxillary barbels about double
length of rostral barbels, ending at insertion of pectoral-fin base, except in 24.4 mm specimen (NRM 41269)
in which extending posterior to pectoral-fin base. Rostral barbels reaching to posterior margin of orbit.
Squamation incomplete in many specimens due to abrasion. Lateral line short, with 4 (1), 5 (7) scales;
scales in lateral row 28 (4), 29 (3), counting scale pockets and remaining scales. Median predorsal scales 15
(2), 16 (4), 17 (1). Lateral scale rows passing between dorsal and pelvic fins 7 (8). Circumpeduncular scale
rows 12 (8). A row of scales along anal-fin base.
D. ii.6½ (19); A. iii.10½ (1), iii.11½ (11), iii.12½ (6); P. i.10 (2), i.11 (8); V. i.7 (10). Dorsal fin inserted at
highest point of dorsum, at about 3/5 distance from head to caudal-fin base, slightly anterior to vertical from
anal-fin origin. Pectoral-fin insertion at about vertical through posterior margin of osseous opercle. Pectoralfin rays long, extending to pelvic-fin origin. Pectoral-fin axial lobe well developed. Pelvic-fin origin situated
at about middle of body, anterior to dorsal-fin origin; pelvic fin reaching to anal-fin origin. Pelvic axillary
scale present. Caudal fin forked, lobes of about equal length.
Vertebrae 15+17=32 (6), 15+18=33 (4), 16+17=33 (4), 17+17=34 (1).
Colouration in preservative. Whitish ground colour. Dorsal scales sparsely pigmented, slightly darker at
rim; except dark brown predorsal midline, and dark brown dorsal midline of caudal peduncle. Horizontal
stripes absent. A series of 6–7 (usually 6) short light brown vertical bars along middle of side anterior to
vertical from anal-fin base, continued posteriorly by two parallel rows of alternating small blotches of the
same colour, lower row comprising 5–7 (usually 6) blotches and running along midline, upper row coalescing
with dorsal pigmentation. Lightly pigmented above anal-fin base and along caudal peduncle below narrow
unpigmented line separating row of blotches. Pigment absent from interspaces between blotches and bars, but
bars and dorsal blotches grading dorsally into diffuse dorsal pigmentation. Dorsal fin hyaline without dark
markings, except that margins of rays may be dark. Caudal fin hyaline, without markings. Pectoral and pelvic
fins hyaline with scattered pigment. Anal fin hyaline, with distinct dark A stripe across middle and less
densely pigmented broad dark band distally on fin.
NEW SPECIES OF DANIO
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TABLE 1. Morphometry of Danio aesculapii. Measurements are in per cent of SL, except for SL and TL (in mm). SD =
standard deviation.
N
Min
Max
Mean
SD
SL (mm)
10
20.0
22.5
21.1
0.93
TL (mm)
8
26.1
30.5
28.2
1.68
Body depth
10
23.1
27.2
25.3
1.13
Head length
10
25.0
27.1
25.4
0.63
Snout length
10
5.7
6.7
6.2
0.34
Head depth
10
15.5
16.9
16.3
0.53
Head width
10
13.1
14.4
13.8
0.40
Upper jaw length
10
8.7
9.5
9.2
0.28
Lower jaw length
10
11.0
12.0
11.6
0.30
Orbital diameter
10
8.5
10.0
9.3
0.38
Interorbital width
10
10.3
11.5
10.9
0.45
Caudal peduncle length
10
18.2
21.0
19.8
0.85
Caudal peduncle depth
10
11.3
12.6
12.0
0.43
Dorsal-fin base length
10
7.7
10.4
9.2
0.85
Anal-fin base length
10
16.9
19.9
18.5
0.95
Predorsal length
10
60.7
64.5
62.6
1.29
Preanal length
10
63.0
65.2
63.9
0.83
Prepelvic length
10
46.5
49.8
48.0
1.09
Pectoral-fin length
9
24.0
26.8
25.4
0.87
Pelvic-fin length
10
11.5
16.1
14.9
1.36
Rostral barbel length
10
7.0
11.3
9.5
1.51
Maxillary barbel length
10
16.8
19.0
18.2
0.69
Molecular data. Nucleotide sequences of the mitochondrial cytochrome b gene and a fragment of the
nuclear rhodopsin gene were obtained from a specimen from the aquarium trade (NRM 52542) and reported
by Fang et al. (2009), with GenBank accession numbers EU241365 and EU241430 (as Danio sp.
“snakeskin”).
Etymology. Genitive of Aesculapius (Latin form of Asklepios, Ἀσκληπιός), Ancient Greek god of
medicine, equipped with a staff with one or two snakes wrapped around it; a reference to the snakeskin pattern
attributed to this species.
Geographical distribution and habitat. Known only from small steams on the western slope of the
Rakhine Yoma, near Thandwe (Fig. 3), Kyeintali and Sittwe. The type locality (Fig. 4) was a small stream
flowing out of the forest into cultivations, at most 3 m wide, and about 30 cm deep. The water was clear with
only slight current and, at the collecting site, concentrated in four pools. There was no aquatic vegetation and
the bottom consisted of pebbles, rock, and gravel. Associated fauna included Anguilla sp. (Anguillidae),
Aplocheilus panchax (Hamilton) (Aplocheilidae), Batasio elongatus Ng and Olyra burmanica Day
(Bagridae), Schistura sp. (Nemacheilidae), Channa sp. (Channidae), Lepidocephalichthys berdmorei (Blyth)
and Pangio pangia (Hamilton) (Cobitidae), Danio sp. aff. dangila, Devario sp., Garra flavatra Kullander &
Fang, G. vittatula Kullander & Fang, Puntius binduchitra (Hora), two species of Puntius Hamilton, Rasbora
daniconius (Hamilton), R. rasbora (Hamilton) (Cyprinidae), Eugnathogobius siamensis (Fowler) and
Sicyopterus fasciatus (Day) (Gobiidae), Mastacembelus armatus (La Cepède) (Mastacembelidae), and
Pterocryptis berdmorei (Blyth) (Siluridae). Other localities near Thandwe included one stagnant pool,
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remnant of a small river, Nan Chaung, at low water level, with leaf litter and sand for bottom substrate, the
other localities being small forest streams with rocky bottoms. The associated fauna varied slightly, but was
essentially dominated by Rasbora, except in Yan Khaw Chaung where an undescribed large species of
Devario was the most abundant species.
FIGURE 3. Danio aesculapii. Collecting sites. The Kyeintali locality at the extreme south is approximate.
NEW SPECIES OF DANIO
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FIGURE 4. Danio aesculapii. Type locality. Myanmar: Rakhine State: Thandwe: Kananmae Chaung, near Leldee
village. 20 March 1998.
Discussion
The fish fauna of the western slope of the Rakhine Yoma includes several endemic species of fishes, most of
them described only recently. They are the cyprinids Puntius binduchitra and Danio feegradei (Hora, 1937),
Garra vitttatula, G. rakhinica, G. flavatra, and G. propulvinus (Kullander & Fang, 2004), the bagrid catfish
Batasio elongatus (Ng, 2004), the erethistid catfish Hara spinulus (Ng & Kottelat, 2007), the akysid catfish
Akysis vespertinus (Ng, 2008), and the channid Channa pulchra (Britz, 2007). We have also identified an
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KULLANDER & FANG
endemic species of Puntius as well as one more undescribed species of Danio, and one undescribed species of
Devario.
Danio aesculapii is the eighth species of the genus described from Myanmar. The others are D. choprae
and D. kyathit from the upper Ayeyarwaddy drainage, D. albolineatus from the Sittoung, Thanlwin, and
Ayeyarwaddy drainages, D. nigrofasciatus from the Sittoung drainage, D. erythromicron and D. margaritatus
from Inle Lake and He Ho plains, respectively, and D. feegradei from near Thandwe. With the exception of
the ubiquitous and abundant D. albolineatus, and the reservation that Myanmar is still not extensively
surveyed ichthyologically, these species have restricted, well circumscribed distributions.
The general colour pattern of D. aesculapii is similar to that of D. choprae from the upper Ayeyarwaddy
drainage. In that species, there are 6–8 short vertical bars, shorter posteriorly and grading into a series of small
spots or short horizontal stripe on the caudal peduncle, representing the P stripe. The P+1 stripe is indistinct in
D. choprae, but the P+2 stripe is distinct and the two merge dorsally on the caudal peduncle. The caudal-fin
stripes characterizing Danio species (Fang 1998: fig. 5) are absent in D. aesculapii, but present in D. choprae.
Danio choprae has a distinct A stripe, like in D. aesculapii, and the distal part of the fin is hyaline, but unlike
in D. aesculapii, the basal part proximal to the A stripe is grayish in D. choprae. Danio choprae also has
shorter maxillary barbels, not reaching to the pectoral fin, and 10 circumpeduncular scale rows, vs. 12 in D.
aesculapii.
The colour pattern of D. aesculapii bears a definite similarity with that of several species of Devario, viz.
the barred danios described and illustrated by Fang (1998; 2000). In these species there is a series of short
vertical bars on the anterior sides, but followed by a horizontal stripe instead of spots posteriorly. Danio
aesculapii is clearly referable to Danio diagnosed by, e.g., the presence of a lateral pad on the dentary, and
absence of a supraorbital groove (cf. Fang, 2003). In position, the lower row of spots in D. aesculapii
corresponds to the posterior section of the P stripe in other Danio, and the upper row of less conspicuous spots
to the P+1 stripe. Homologous marks of other horizontal stripes cannot be traced.
Danio aesculapii is distinctive also for the circumpeduncular scale count (12), shared only with D. kerri,
and D. erythromicron. All other small species of Danio have 10, the larger species D. dangila, D. feegradei
and D. meghalayensis 14. In D. margaritatus we obtain counts of 9 and 10. The dorsal-fin count of D.
aesculapii, with six branched rays, is unique in the genus. In other small species of Danio there are two
unbranched rays, followed by seven or eight branched rays and one unbranched ray with the same base as the
preceding branched ray (the “half-ray” of e.g., Kottelat (2007)), but which is usually included in the preceding
ray by most authors. In D. aesculapii there are two unbranched followed by six branched rays, and a half-ray
that may be closely apposed the preceding ray or slightly distinct from it. Larger species of Danio (D.
feegradei, D. dangila, and D. meghalayensisi) have eight or nine branched dorsal-fin rays. The reduced
dorsal-fin count is an autapomorphy within the genus, and not necessarily associated with small size because
other small species in the genus have seven branched rays, and one examined specimen of D. margaritatus
has eight branched rays. Specimens of D. jaintiaensis (Sen, 2007) have not been available for examination;
the information and illustrations in the original description (Sen, 2007), however, suggest that this species has
the usual seven branched dorsal-fin rays and 10 circumpeduncular scale rows.
Danio aesculapii has a relatively basal position in the rhodopsin tree presented by Fang et al. (2009: fig.
3), sister to all other Danio except D. dangila. In the cytochrome b and combined trees (Fang et al. 2009: figs.
3–4), however, it groups with D. nigrofasciatus, D. kyathit, and D. sp. ‘Ozelot’ in a sister group assemblage to
D. kerri, D. albolineatus, D. roseus, and D. rerio, whereas in turn D. choprae, D. margaritatus, and D.
erythromicron form sister group to those two assemblages. This suggests that the similarity in colour pattern
between D. aesculapii and D. choprae must have been independently derived, as D. aesculapii is contained in
a group of striped species.
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Acknowledgements
Specimens were collected during a field survey supported by a grant to S.O. Kullander from the Swedish
Natural Science Research Council (RA 04568-316). We are indebted to our guide Thein Win for considerable
effort in the field work, Ralf Britz for sharing field work, contributing more specimens from his own
collection, and commenting on the manuscript, and Tan Heok Hui and an anonymous reviewer for
constructive comments on the manuscript. Permission to collect and export specimens was granted by the
Fisheries Department, Yangon.
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