A NEW CRYPTIC TREE FROG SPECIES ALLIED TO Kurixalus banaensis (ANURA: RHACOPHORIDAE) FROM VIETNAM

Abstract

A new species of the genus Kurixalus is described from the Central Highlands of Vietnam based on molecular phylogenetic and morphological analyses. Morphologically, Kurixalus motokawai sp. nov. is most similar to K. banaensis but they are clearly separated from each other in mitochondrial DNA sequences. In phylogenetic analysis the new species clustered in the same clade with Kurixalus banaensis and K. viridescens. However, the new species differs from K. banaensis by having a smaller body size, a higher ratio of forelimb length/SVL in both sexes, a smaller ratio of first toe length/SVL in males, snout tip less markedly pointed, and only weakly developed dermal appendages on the outer edges of fore-and hindlimbs. Kurixalus motokawai sp. nov. also differs from K. viridescens by having a smaller size in females and a brown dorsum with dark markings.

Full text

A NEW CRYPTIC TREE FROG SPECIES ALLIED TO Kurixalus banaensis
(ANURA: RHACOPHORIDAE) FROM VIETNAM
Nguyen Thien Tao,1Masafumi Matsui,2and Koshiro Eto2,3
Submitted September October 21, 2014.
A new species of the genus Kurixalus is described from the Central Highlands of Vietnam based on molecular
phylogenetic and morphological analyses. Morphologically, Kurixalus motokawai sp. nov. is most similar to
K. banaensis but they are clearly separated from each other in mitochondrial DNA sequences. In phylogenetic
analysis the new species clustered in the same clade with Kurixalus banaensis and K. viridescens. However, the
new species differs from K. banaensis by having a smaller body size, a higher ratio of forelimb length/SVL in
both sexes, a smaller ratio of first toe length/SVL in males, snout tip less markedly pointed, and only weakly
developed dermal appendages on the outer edges of fore- and hindlimbs. Kurixalus motokawai sp. nov. also differs
from K. viridescens by having a smaller size in females and a brown dorsum with dark markings.
Keywords: Kurixalus motokawai sp. nov.; mtDNA phylogeny; taxonomy; Central Highlands; Gia Lai Province;
Kon Tum Province.
INTRODUCTION
The genus Kurixalus Ye, Fei, and Dubois, 1999 has a
restricted range in Asia, from eastern India through
Myanmar and mountainous southern China, southward to
southern Cambodia and central Vietnam, through west-
ern and northern peninsular Thailand to Malaya, Suma-
tra, Borneo, and the Philippines (Frost, 2014). Recent
phylogenetic analyses showed that Kurixalus species are
taxonomically confused (Yu et al., 2010; Li et al., 2013;
Nguyen et al., 2014). From Vietnam, Nguyen et al.
(2009) recorded five species of Kurixalus, viz.
K. ananjevae (Matsui et Orlov), K. baliogaster (Inger,
Orlov, and Darevsky), K. carinensis (Boulenger), K. odo-
ntotarsus (Ye et Fei), and K. verrucosus (Boulenger). Of
these, K. carinensis has been placed in Gracixalus and
Philautus banaensis Bourret was transferred to the genus
Kurixalus (Li et al., 2009). Additionally, Yu et al. (2010)
have suggested that previous records of K. odontotarsus
and K. verrucosus from Vietnam should be assigned to
K. bisacculus. Recently, Nguyen et al. (2014) described
the green Kurixalus form from southern Vietnam as a
new species, namely K. viridescens Nguyen, Matsui et
Hoang. Thus, five Kurixalus species are left being valid
in Vietnam at present, although eight species are listed in
Frost (2014).
During our recent fieldwork in the Central Highlands
of Vietnam, a small tree frog species was collected and
provisionally identified as Kurixalus banaensis. How-
ever, the newly collected specimens have a smaller size
and only weakly pronounced skin ornamentation com-
pared with the latter. Molecular phylogenetic comparison
revealed that they are genetically distinct from each
other. Therefore, we herein describe the tree frog from
Kon Tum and Gia Lai provinces, Vietnam as a new
species.
MATERIAL AND METHODS
DNA sequence data from our new samples were
combined with a previously collected mitochondrial se-
quence dataset for species of Kurixalus and relevant
out-groups, including Buergeria japonica and Raorches-
tes gryllus (Li et al., 2013; Nguyen et al., 2014; Table 1).
We used the same methods for DNA extraction, and am-
plification and sequencing of the mtDNA fragments as
those reported by Kuraishi et al. (2013). The resultant
sequences (435 base pairs [bp] of partial sequences of
mitochondrial 16S rRNA gene) were deposited in
GenBank (accession numbers LC 002885 – 002915).
Measurements were taken with digital calipers to the
nearest 0.1 mm. Morphological terminology follows
1026-2296/2014/2104-0295 © 2014 Folium Publishing Company
Russian Journal of Herpetology Vol. 21, No. 4, 2014, pp. 295 – 302
1Department of Nature Conservation, Vietnam National Museum of
Nature, Vietnam Academy of Science and Technology, 18 Hoang
Quoc Viet Road, Hanoi, Vietnam;
e-mail: nguyenthientao@gmail.com
2Graduate School of Human and Environmental Studies, Kyoto Uni-
versity, Sakyo, Kyoto 606-8501, Japan;
e-mail: fumi@zoo.zool.kyoto-u.ac.jp
3Kyoto University Museum, Sakyo, Kyoto 606-8501, Japan;
e-mail: koshiro.eto@gmail.com

296 Nguyen Thien Tao et al.
TABLE 1. Sample of Kurixalus sp. and Other Species Used for DNA Analysis in This Study Together with the Information on Voucher, Collection
Locality and GenBank Accession Numbers
Voucher Species GenBank Locality Reference
VNMN 03416 Kurixalus sp. LC002886 Vietnam, Kon Tum This study
VNMN 03457 Kurixalus sp. LC002887 Vietnam, Kon Tum This study
VNMN 03458 Kurixalus sp. LC002888 Vietnam, Kon Tum This study
VNMN 03575 Kurixalus sp. LC002889 Vietnam, Kon Tum This study
VNMN 03576 Kurixalus sp. LC002890 Vietnam, Kon Tum This study
VNMN 03577 Kurixalus sp. LC002891 Vietnam, Kon Tum This study
VNMN 03606 Kurixalus sp. LC002892 Vietnam, Kon Tum This study
VNMN 03722 Kurixalus sp. LC002893 Vietnam, Kon Tum This study
VNMN 03726 Kurixalus sp. LC002894 Vietnam, Kon Tum This study
VNMN 03735 Kurixalus sp. LC002895 Vietnam, Kon Tum This study
VNMN 03739 Kurixalus sp. LC002896 Vietnam, Kon Tum This study
VNMN 03757 Kurixalus sp. LC002897 Vietnam, Kon Tum This study
VNMN 03758 Kurixalus sp. LC002898 Vietnam, Kon Tum This study
VNMN 04006 Kurixalus sp. LC002899 Vietnam, Gia Lai This study
VNMN 04015 Kurixalus sp. LC002900 Vietnam, Kon Tum This study
VNMN 04027 Kurixalus sp. LC002901 Vietnam, Kon Tum This study
VNMN 04028 Kurixalus sp. LC002902 Vietnam, Kon Tum This study
VNMN 03802 Kurixalus viridescens AB933284 Vietnam, Khanh Hoa Nguyen et al. (2014)
VNMN 03813 Kurixalus viridescens AB933285 Vietnam, Khanh Hoa Nguyen et al. (2014)
VNMN 03814 Kurixalus viridescens AB933286 Vietnam, Khanh Hoa Nguyen et al. (2014)
VNMN 03461 Kurixalus banaensis LC002903 Vietnam, Kon Tum This study
VNMN 03909 Kurixalus banaensis LC002904 Vietnam, Kon Tum This study
VNMN 04016 Kurixalus banaensis LC002905 Vietnam, Lam Dong This study
VNMN 04017 Kurixalus banaensis LC002906 Vietnam, Gia Lai This study
VNMN 04018 Kurixalus banaensis LC002907 Vietnam, Binh Phuoc This study
VNMN 04019 Kurixalus banaensis LC002908 Vietnam, Kon Tum This study
VNMN 04020 Kurixalus banaensis LC002909 Vietnam, Kon Tum This study
VNMN 04021 Kurixalus banaensis LC002910 Vietnam, Kon Tum This study
VNMN 04022 Kurixalus banaensis LC002911 Vietnam, Kon Tum This study
VNMN 04023 Kurixalus banaensis LC002912 Vietnam, Kon Tum This study
VNMN 04024 Kurixalus banaensis LC002913 Vietnam, Kon Tum This study
VNMN 04025 Kurixalus banaensis LC002914 Vietnam, Kon Tum This study
VNMN 04026 Kurixalus banaensis LC002915 Vietnam, Kon Tum This study
VNMN 03809 Kurixalus bisacculus AB933295 Vietnam, Thanh Hoa Nguyen et al. (2014)
KUHE 35069 Kurixalus bisacculus AB933291 Thailand, Kanchanaburi Nguyen et al. (2014)
CIB K 2805 Kurixalus bisacculus AB933289 China, Guangxi Nguyen et al. (2014)
VNMN 03618 Kurixalus baliogaster AB933300 Vietnam, Kon Tum Nguyen et al. (2014)
VNMN 03652 Kurixalus baliogaster AB933299 Vietnam, Kon Tum Nguyen et al. (2014)
VNMN 03811 Kurixalus baliogaster AB933297 Vietnam, Gia Lai Nguyen et al. (2014)
KIZ 201307012 Kurixalus odontotarsus AB933302 China, Yunnan Nguyen et al. (2014)
KIZ 201307071 Kurixalus odontotarsus AB933303 China, Yunnan Nguyen et al. (2014)
CAS 231489 Kurixalus verrucosus KC465823 Myanmar, Kachin Li et al. (2013)
RAO 6305 Kurixalus verrucosus KC465825 Cina, Xizang Li et al. (2013)
KUHE 12910 Kurixalus eiffingeri AB933305 Japan, Iriomote Is. Nguyen et al. (2014)
KUHE 12979 Kurixalus idiootocus AB933306 Taiwan, Jiayi Nguyen et al. (2014)
KUHE 53614 Kurixalus appendiculatus AB847125 Borneo, Sarawak Matsui et al. (2014)
KUHE 55238 Raorchestes gryllus AB933309 Vietnam, Tam Dao Nguyen et al. (2014)
RUE 1185 Buergeria japonica LC002885 Japan, Amamioshima This study
Voucher abbreviations: CAS, California Academy of Sciences; CIB, Chengdu Institute of Biology; KIZ, Kunming Institute of Zoology;
KUHE, Graduate School of Human and Environmental Studies, Kyoto University; RAO, field number of Ding-qi Rao; RUE, Faculty of Education,
University of the Ryukyus; VNMN, Vietnam National Museum of Nature.

Matsui (1984, 1994) and Nguyen et al. (2014). The fol-
lowing abbreviations were used: SVL, snout-vent length;
HL, head length; HW, head width; IND, internarial dis-
tance; IOD, interorbital distance; UEW, upper eyelid
width; N-EL, nostril-eye distance; SL, snout length;
EL, eye length; ED, eye diameter; TD, tympanum diame-
ter; T-EL, tympanum-eye length; FLL, forelimb length;
LAL, lower arm and hand length; 1FL, first finger length
(measured from distal edge of inner palmar tubercle);
IPTL, inner palmar tubercle length; HLL, hindlimb
length; HLL, tibia length; FL, foot length; IMTL, inner
metatarsal tubercle length; 1TOEL, first toe length.
Measurements of finger and toe disks in the holotype
were taken to the nearest 0.01 mm using a binocular dis-
secting microscope equipped with a micrometer: first to
fourth finger disk diameter (1 – 4FDW); and first to fifth
toe disk diameter (1 – 5TDW).
Statistical comparisons were made between two
groups separated by molecular analysis. In the univariate
comparisons, SVL was compared by Tukey – Kramer
test, but the remaining characters, converted to ratios to
SVL (R), were compared by Dunn’s multiple compari-
sons test. For description of toe-webbing states we fol-
lowed the system of Savage (1975). Specimens examined
are deposited in the collection of the Vietnam National
Museum of Nature (VNMN), Hanoi, Vietnam.
SYSTEMATICS
In our phylogenetic analysis, the undescribed species
of Kurixalux from Vietnam was clustered in the same
group with K. banaensis and K. viridescens, although
their relationships were not resolved (Fig. 2). This group
is a sister clade of the K. verrucosus group, containing
K. verrucosus from southern China and Myanmar,
K. odontotarsus from southern China, K. baliogaster
from Central Highlands of Vietnam and K. bisacculus
from China, Vietnam and Thailand. The specimens of
Kurixalus sp. from Central Highlands exhibited dis-
tinctly large genetic distances from the nine examined
species of Kurixalus with uncorrected p-distance of 8.4 –
17.2% (see Table 2). Whereas, genetic distance (uncor-
A New Kurixalus from Vietnam 297
Fig. 1. Map showing the distribution of Kurixalus motokawai sp. nov.
in Vietnam: 1, Kon Plong in Kon Tum Province (type locality); 2, Dak
Glei in Kon Tum Province; 3, K’Bang in Gia Lai Province.
Fig. 2. ML tree from a 435 bp sequence of mitochondrial 16S rRNA
gene for Kurixalus species and out-groups. ML inferences (ML-BS) >
70% /Bayesian posterior probabilities (BPP) > 95% are shown near the
node.

rected p-distance) between specimens of Kurixalus sp.
from Gia Lai and Kon Tum provinces ranged from 0 to
1.5%. In addition, Kurixalus sp. is also distinguished
from other congeners by some morphological characters.
Thus, we describe the species of Kurixalus from Central
Highlands of Vietnam as a new species as follows:
Kurixalus motokawai sp. nov.
Figs. 3 and 4
Holotype. Adult male VNMN 03458, collected by
Tao Thien Nguyen, at 20:00 on 8 September 2012 in
Mang Canh forest (14°40¢33¢¢ N 108°14¢37¢¢ E, 1230 m
a.s.l.), Kon Plong District, Kon Tum Province, Central
Highlands of Vietnam.
Paratypes. VNMN 03416, 03457, 03557, 03575,
03576, 03577, 03590, 03606, the same data as the
holotype; VNMN 04028 (2012.113), collected by Tao
Thien Nguyen and Chung Van Hoang from 19:00 to
22:00 on 12 October 2012 near Dak Man Ranger Station
(15°12’45¢¢ N 107°44’15¢¢ E, 1150 m a.s.l.), Ngoc Linh
Nature Reserve, Dak Glei District, Kon Tum Province;
VNMN 03574, 04006 (KKK 2012.101), collected by Tao
Thien Nguyen on 23 February 2012 from Kon Ka Kinh
National Park (14°13’23¢¢ N 108°19’15¢¢ E, 1050 m
a.s.l.), K’Bang District, Gia Lai Province.
298 Nguyen Thien Tao et al.
TABLE 2. Uncorrected p-Distances (%) for Fragment of 16S rRNA between Kurixalus and Related Taxa
1234567891011
1Kurixalus sp.
2K. banaensis 8.6 – 9.9
3K. viridescens 9.9 – 11.4 7.6 – 9.4
4K. bisacculus 9.1 – 9.9 10.1 – 11.1 9.1 – 11.1
5K. baliogaster 8.9 – 9.4 8.6 – 10.1 8.4 – 10.9 2.8 – 3.5
6K. odontotarsus 9.4 – 9.9 8.1 – 9.6 8.6 – 11.1 3.8 3.8 – 4.1
7K. verrucossus 8.4 – 10.9 8.6 – 9.6 8.6 – 9.9 6.1 – 6.6 6.1 – 6.3 5.3 – 6.3
8K. idiootocus 10.4 – 10.6 10.1 – 12.2 10.6 – 12.9 10.1 – 11.1 10.1 – 10.4 9.4 8.1 – 9.4
9K. eiffingeri 12.2 – 12.4 10.4 – 11.1 11.1 – 13.2 10.6 – 11.6 9.6 – 9.9 9.6 8.9 – 9.6 5.3
10 K. appendiculatus 16.5 – 17.2 16.7 – 17.7 18.7 – 19.5 18.0 – 19.0 19.0 – 19.2 18.2 16.5 – 17.0 15.9 16.7
11 Raorchestes gryllus 18.0 – 18.5 17.0 – 18.7 17.2 – 17.7 17.5 – 18.5 17.7 – 18.0 18.0 18.5 – 18.5 17.2 14.9 18.5
12 Buergeria japonica 17.5 – 18.2 15.7 – 17.7 19.0 15.4 – 16.2 15.9 – 16.2 16.7 14.7 – 16.7 16.7 15.2 17.0 16.7
A B
Fig. 3. Dorsal (A) and ventral (B) views of the male holotype (VNMN 03458) of Kurixalus motokawai sp. nov. in preservative. Scale bar is
10 mm.

Referred specimens. VNMN 03722, VNMN 03726,
VNMN 03735, VNMN 03739, VNMN 03757, VNMN
03758, VNMN 04015, and VNMN 04027, all from Kon
Tum Province.
Etymology. The species name is dedicated to Asso-
ciate Professor Dr. Masaharu Motokawa from the Kyoto
University, who is an eminent mammalogist and continu-
ously supports the senior author in his study and his
outstanding contribution to biodiversity research in
Vietnam.
Diagnosis. The new species was assigned to the ge-
nus Kurixalus by a combination of the following mor-
phological characters: small-sized rhacophorid (SVL <
50 mm); tips of digits enlarged to the discs, bearing cir-
cummarginal grooves; snout tip pointed; finger webbing
poorly developed; dermal fringes present on forearm and
tarsus (Bourret, 1939; Taylor, 1962, Matsui and Orlov,
2004, Yu et al, 2010). The new species is unambiguously
nested in the genus Kurixalus by molecular phylogenetic
evidence, closely related to K. banaensis and K. viride-
scens. The specimens from Central Highlands differ from
K. viridescens by the color pattern and body size and
from K. banaensis by having a smaller size and weakly
developed skin ornamentations.
Description of holotype. SVL 27.8 mm; body mod-
erately robust; head as long as wide (HL 10.8 mm, HW
10.8 mm, 38.8% of SVL); snout (SL 4.2 mm, 15.1% of
SVL) shorter than eye (EL 4.5 mm, 16.2% of SVL), dor-
sally pointed at tip, sloping anteroventrally in profile,
projecting over lower jaw; canthus slightly blunt; loreal
region oblique, concave; nostril protuberant, closer to the
tip of snout than to eye; internarial distance (IND
3.0 mm, 10.8% of SVL) as wide as interorbital (IOD
3.0 mm, 10.8% of SVL); narrower than upper eyelid
(UEW 3.2 mm, 11.5% of SVL); pineal spot present; eye
large, protuberant, diameter (ED 3.8 mm, 13.7% of SVL)
much larger than nostril-eye distance (N-EL 1.8 mm,
6.5% of SVL); pupil horizontal; tympanum distinct,
subcircular, its diameter (TD 1.7 mm, 6.1% of SVL) less
than half eye diameter and separated from eye by one-
third of tympanum diameter (E-TL 0.6 mm, 2.2% of
SVL); vomerine teeth absent; tongue deeply notched
posteriorly.
Forelimb moderate (FLL 18.1 mm, 65.1% of SVL);
relative finger lengthsI<II<IV<III; length of first fin-
ger (1FL 2.4 mm, 8.6% of SVL) much shorter than diam-
eter of eye; tips of all fingers dilated into horizontally
elongate large disks with circummarginal and transverse
ventral grooves; third and fourth finger disks (3FDW
1.1 mm, 3.8% of SVL; 4FDW 1.1mm, 4.0% of SVL) nar-
rower than tympanum diameter; fingers with poorly de-
veloped webbing, formula I2 – 23/4II2–2
1/2III21/2–
2IV; fringe of skin on edge of fingers; subarticular tuber-
cles distinct, rounded, formula 1, 1, 2, 2; supernumerary
tubercles on metacarpal absent; prepollex prominent,
oval; inner palmar tubercle distinct (IPTL 2.1 mm, 7.6%
SVL), outer palmar tubercles two, small.
Hindlimb long (HLL 42.6, 153.2% SVL), about 2.4
times length of forelimb; tibia not long (TL 13.8, 49.6%
SVL), heels overlapping when limbs are held at right an-
gles to body; tibiotarsal articulation of adpressed limb
reaching middle of eye; foot (FL 10.6, 38.1% SVL)
shorter than tibia; relative length of toesI<II<III<V<
IV; tips of toes expanded into round disks with distinct
circummarginal grooves, subequal to those of fingers
(3TDW 1.1 mm, 3.9% of SVL; 4TDW 1.1 mm, 4.0% of
SVL; 5TDW 1.0 mm, 3.7% of SVL); toe webbing mod-
erately developed, formula I2 – 2II1/3– 2III1 –
21/2IV21/2–1
1/2V; subarticular tubercles distinct,
rounded, formula 1, 1, 2, 3, 2; supernumerary tubercles
absent; inner metatarsal tubercle distinct, oval (IMTL
1.3 mm, 4.7% of SVL), about half length of first toe
(1TOEL 2.7 mm, 9.7% of SVL); outer metatarsal tu-
bercle absent.
Skin. Dorsum with sparsely distributed small tu-
bercles; supratympanic fold distinct, running from eye
above tympanum, ending at above arm insertion; lateral
sides and abdomen areolate; a weakly developed ridge of
skin on outer edge of forearm forming a weak serration;
hindlimb smooth, except for a weak serration along outer
edge of tarsus and fifth toe; tubercles including two pairs
of large conical ones posteroventral to cloaca; heel with
small triangle dermal appendage.
A New Kurixalus from Vietnam 299
AB
Fig. 4. Dorsal views of right hand (A) and foot (B) of the male
holotype (VNMN 03458) of Kurixalus motokawai sp. nov. in preserva-
tive. Scale bar is 5 mm.

Coloration. In preservative, ground color of head
and body grayish brown with large dark brown marking
except for upper eyelid, shoulder, and post-sacral re-
gions. Lateral head and tympanic region grayish brown
with a dark bar below canthus. Limbs dorsally grayish
brown with dark brown marking, forming crossbars on
lower arm, tibia, and tarsus. Ventral surface white, scat-
tered with dark brown spots on chin, lower part of flanks,
and limbs except for thigh. Rear of thigh mottled with
dark spots. Infra-cloacal region white. Hand and foot
ventrally grayish brown scattered with dark spots.
Variation. Morphometric data are summarized in
Table 3. Because only one female was available, sexual
dimorphism could not be determined statistically, but a
single female has the size (SVL 25.1 mm) within the
variation range of males (23.2 – 28.4 mm, mean 26.1 ±
1.46 mm). In some paratypes, head is wider than long,
IND is smaller than IOD, and IOD is smaller than UEW
(2 specimens). The tibiotarsal articulation reaches the
center of the eye (9 specimens), to anterior corner of the
eye (6 specimens), or to between eye and nostril (1 speci-
men). Some individuals have conical dermal appendage
at the snout and/or heel. Coloration in life is variable,
some individuals have a dorsum tinged with green (see
Fig. 5).
Comparisons. The new species, K. motokawai sp.
nov., is morphologically similar to K. banaensis, but they
can be distinguished from each other in the body size.
The males of K. motokawai sp. nov. are smaller than
those of K. banaensis (SVL 23.2 – 28.4 mm, mean ± SD
26.1 ± 1.46 mm, versus 26.2 – 33.2 mm, mean ± SD
29.7 ± 2.43 mm, Tukey – Kramer test, P< 0.01) (see
Tables 4 and 5). In terms of proportions, K. motokawai
has a higher value of RFLL in both sexes (ratio of fore-
limb length/SVL) but smaller value of R1TOEL in males
(ratio of first toe length/SVL) (Dunn’s multiple compari-
son test, P< 0.05) (see Table 6). These species also differ
from each other in the shape of the snout tip and the
dermal appendage at cloaca (snout tip less markedly
pointed and lateral fringes on limbs and infra-cloacal
tubercles less developed in K. motokawai sp. nov. than
in K. banaensis).
The new species differs from K. viridescens by hav-
ing a smaller size in females (SVL 25 mm vs. 29 –
37 mm in K. viridescens) and a brown dorsum with dark
markings (vs. green dorsum without markings in K. viri-
descens); from K. ananjevae (Matsui and Orlov, 2004) by
having a smaller size (male SVL 23 – 28 mm, female
SVL 25 mm vs. male 32 mm, female 43 mm in
K. ananjevae) and the presence of dermal ornamentations
(absent in K. ananjevae); from K. appendiculatus (Gün-
300 Nguyen Thien Tao et al.
TABLE 3. Measurements of adult specimens of Kurixalus motokawai sp. nov. and K. banaensis
K. motokawai K. banaensis
17 x1}6x4}
SVL 26.1 ± 1.46 (23.2 – 28.4) 25.1 29.7 ± 2.43 (26.2 – 33.2) 33.9 ± 2.71 (30.5 – 37.0)
RHL 39.8 (36.4 – 42.4) 41.4 40.1 (39.2 – 41.6) 38.8 (37.7 – 42.5)
RHW 40.5 (36.4 – 44.2) 40.2 41.0 (37.5 – 42.4) 39.1 (37.0 – 42.8)
RIND 10.2 (8.8 – 11.7) 11.6 10.1 (9.6 – 10.7) 10.2 (8.1 – 11.0)
RIOD 12.0 (10.8 – 14.1) 12.7 11.3 (10.3 – 13.4) 11.0 (9.8 – 12.1)
RUEW 11.3 (8.8 – 13.4) 11.6 11.8 (8.8 – 13.0) 11.2 (11.1 – 11.5)
RSL 15.6 (13.8 – 17.4) 16.3 15.8 (14.7 – 17.8) 15.0 (14.3 – 15.6)
RN-EL 8.4 (6.5 – 10.9) 8.8 9.2 (8.0 – 11.1) 8.6 (7.5 – 9.0)
REL 17.1 (15.3 – 20.3) 18.3 17.2 (16.8 – 18.4) 16.1 (14.6 – 17.4)
RED 14.7 (13.7 – 15.3) 14.7 14.5 (14.1 – 15.7) 13.8 (13.8 – 13.8)
RTD 6.1 (4.5 – 7.1) 6.4 5.8 (5.6 – 6.6) 6.1 (5.2 – 7.5)
RE-TL 1.5 (0.7 – 2.4) 2.0 1.4 (1.1 – 1.6) 1.7 (0.9 – 2.0)
RLAL 49.3 (46.8 – 54.7) 47.0 48.7 (44.2 – 49.8) 46.5 (45.1 – 49.2)
RFLL 65.1 (61.6 – 70.3) 62.5 60.7 (59.1 – 63.6) 59.6 (58.9 – 60.5)
RIPL 5.8 (4.1 – 7.6) 6.4 5.3 (4.0 – 6.3) 4.8 (4.3 – 5.6)
R1FL 8.4 (7.6 – 9.9) 8.8 8.7 (8.0 – 12.8) 9.2 (7.8 – 10.2)
RTL 49.3 (45.5 – 52.8) 50.2 50.4 (44.9 – 51.6) 50.5 (47.0 – 55.4)
RFL 40.2 (37.7 – 51.6) 39.4 42.5 (38.5 – 44.9) 41.9 (35.4 – 43.3)
RHLL 152.0 (144.0 – 161.8) 155.4 157.2 (136.1 – 166.7) 156.2 (142.2 – 165.0)
RIMTL 4.6 (3.0 – 5.7) 6.0 4.8 (3.7 – 5.8) 5.4 (4.3 – 5.9)
R1TOEL 8.2 (7.3 – 10.3) 8.0 9.5 (9.0 – 11.6) 8.4 (8.1 – 10.8)
Notes. SVL (mean ± SD, in mm) and medians of percentage ratios (R) of other characters to SVL, followed by ranges in parenthesis. See text for char-
acter abbreviations.

ther) in having a smaller size in males (SVL 23 – 28 mm
vs. 30 – 37 mm), infra-cloacal appendage with several
conical tubercles (vs. dermal flap), and vomerine teeth
absent (vs. present in K. appendiculatus); from K.
baliogaster by having a smaller size in males (SVL
23 – 28 mm vs. 33 mm), ventral surface scattered with
small dark spots and lacking a rostral cone in females (vs.
ventral surface with conspicuous, large black spots, fe-
males with a strong rostral cone in K. baliogaster); from
K. bisacculus by having a smaller size in females (SVL
25 mm vs. 29 mm), belly immaculate white (vs. belly
with black spots), and vomerine teeth absent (vs. present
in K. bisacculus).
The new species differs from K. eiffingeri (Boettger)
by having a smaller size (male SVL 23 – 28 mm vs.
31 – 35 mm and female SVL 25 mm vs. 32 – 44 mm)
and serrated lateral skin on lower arm, tibia, and tarsus
(vs. lateral skin with a row of tubercles in K. eiffingeri);
from K. idiootocus (Kuramoto et Wang) by the presence
of serrated dermal fringe on lower arm, tibia, and tarsus;
from K. naso (Annandale), K. motokawai differs by body
size, snout shape, toe webbing, and ventral color (male
SVL 23 – 28 mm and female SVL 25 mm, snout tip
weakly pointed, toe webbing poorly developed, and ven-
tral surface scattered with small dark spots vs. SVL
43 mm, snout with a cone, toe webbing well-developed,
and chin and breast marked with dark reticulation in
K. naso); from K. odontotarsus by having a smaller size
(male SVL 23 – 28 mm and female 25 mm vs. 30 –
33 mm and 35 – 43 mm, respectively), snout weakly
pointed (vs. sharply pointed), and ventral surface scat-
tered with small dark spots (vs., venter with large dark
markings in K. odontotarsus); from K. verrucosus by
having smaller size in female (SVL 25 mm vs. 43 –
45 mm), belly without dark spots (vs. present), and toe
webbing moderately developed (well developed in
K. verrucosus).
Distribution. K. motokawai is currently known from
several localities in the Central Highlands of Vietnam:
Kon Plong forest and Ngoc Linh Nature Reserve in Kon
Tum Province, and Kon Ka Kinh National Park in
K’Bang District, Gia Lai Province, at elevations from
1050 m to 1230 m a.s.l.
Natural history. Surrounding habitat at the type lo-
cality of the species in Kon Plong District, Kon Tum
Province was the primary rain-forest, inclined slopes of
the mountains at elevations of 1100 – 1400 m a.s.l. All
specimens were collected at night, from 19:00 to 23:00.
The specimens were found on leaves of scrub vegetation
and young trees, about 0.5–1mabove the ground. Asso-
ciated species observed at the type locality were Gracixa-
lus supercornutus (Orlov, Ho et Nguyen), Raorchestes
gryllus (Smith) and Rhacophorus robertingeri Orlov,
Poyarkov, Vassilieva, Ananjeva, Nguyen, Nguyen et
Geissler.
A New Kurixalus from Vietnam 301
Fig. 5. Male paratype (VNMN 04006) of Kurixalus motokawai sp.
nov. in life.
TABLE 4. Comparison of the size (average SVL) between Kurixalus
motokawai sp. nov. and K. banaensis
Species NMean Standard
deviation
1. Kurixalus motokawai (x)17 26.017 1.465
2. Kurixalus banaensis (x)6 29.683 2.428
3. Kurixalus banaensis (})4 33.900 2.712
Total 27 28.033 3.427
TABLE 5. One way ANOVA Test and Tukey – Kramer Test of the Size (Average SVL) between Kurixalus motokawai sp. nov. and K. banaensis
Comparison Difference SE qConclusion
Kurixalus banaensis (}) vs. K. motokawai (x)7.829 0.743 10.534* K. banaensis (})>K. motokawai (x)
K. banaensis (}) vs. K. banaensis (x)4.217 0.863 4.884* K. banaensis (})>K. banaensis (x)
K. banaensis (x) vs. K. motokawai (x)3.613 0.635 5.688* K. banaensis (x)K. motokawai (x)
Notes. One way ANOVA test: df = 2.24, F= 30.6760, p= 0.0000; Tukey – Kramer test: if q>q(0.05, 3, 24) = 3.532, then significant (*), else not
significant.

DISCUSSION
Generally, small rhacophorids with brown dorsum
are difficult to identify and identification should be ide-
ally made with reference to type specimens. Kurixalus
motokawai has been confused with K. banaensis for a
long time (e.g., Nguyen et al., 2009). Kurixalus banaen-
sis was originally described by Bourret (1939) in the
genus Philautus from Bana (= Ba Na, Da Nang City,
Vietnam). In the Muséum national d’Histoire naturelle
(MNHN) in Paris, currently three syntypes (MNHN
1948.0159 – 0161) are deposited, together with a topo-
type (MNHN 1948.0162). Bossuyt and Dubois (2001)
designated the lectotype (MNHN 1948.0160) and pro-
vided a redescription of this species. Our examination of
the lectotype revealed some additional characters for the
original description of Bourret (1939): snout clearly
pointed; canthus distinct; tympanum indistinct; webbing
between second and third fingers, and third and fourth
fingers not rudimentary; dermal fringe on side of upper
arm and tarsus serrated; triangular skin projections pres-
ent below cloaca; interorbital with dark markings. Fur-
thermore, the topotype has a pineal spot and round snout,
and toe webbing formula of I11/2– 2II11/3– 2III11/2–
21/2IV2–1
1/2V. In our molecular analyses, the new spe-
cies, K. viridescens, and K. banaensis tended to form a
group, which we propose to call the K. banaensis species
group. Because the new species and K. banaensis are su-
perficially similar, previous records of K. banaensis in
Vietnam need to be verified by further studies. Finally,
comparison of advertisement calls may help to elucidate
bioacoustic differences between K. motokawai and
K. banaensis.
Acknowledgments. We thank the directorates of the Forest
Protection Departments of Kon Tum and Gia Lai provinces,
Ngoc Linh Nature Reserve and Kon Ka Kinh National Park for
issuing relevant permits and support of our fieldwork.
T. T. Nguyen thanks C. V. Hoang (Hanoi), Y. Kawahara and
N. Kuraishi (Kyoto) for field and laboratory assistance.
M. Matsui thanks A. Dubois and A. Ohler (Paris) for allowing
him to examine specimens under their care. We thank T. Ziegler
(Cologne) and N. L. Orlov (Saint Petersburg) for their helpful
comments. Thanks to E. Sterling (New York) and Kevin Koy
(Berkeley) for providing the map. Field work was partly sup-
ported by the Project TN3/T07 of the National Program Tay
Nguyen III and STMVQG. 06/14-16 to T. T. Nguyen, the grant
from the Japan Society for the Promotion of Science (JSPS AA
Science platform Program, FY2011 – 2013) to M. Motokawa,
Grants-in Aid from the Monbusho through the Japan Society
for the Promotion of Science (Field Research, Nos. 15370038,
20405013 and 23405014) to M. Matsui. Research of
T. T. Nguyen in Japan is funded by the JSPS RONPAKU Pro-
gram (VAST-11224).
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