Research Article |
Corresponding author: L. Lee Grismer ( lgrismer@lasierra.edu ) Corresponding author: Nikolay A. Poyarkov ( n.poyarkov@gmail.com ) Academic editor: Raffael Ernst
© 2021 Chatmongkon Suwannapoom, L. Lee Grismer, Parinya Pawangkhanant, Mali Naiduangchan, Platon V. Yushchenko, Dmitriy V. Arkhipov, Jeffery A. Wilkinson, Nikolay A. Poyarkov.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Suwannapoom C, Grismer LL, Pawangkhanant P, Naiduangchan M, Yushchenko PV, Arkhipov DV, Wilkinson JA, Poyarkov NA (2021) Hidden tribe: A new species of Stream Toad of the genus Ansonia Stoliczka, 1870 (Anura: Bufonidae) from the poorly explored mountainous borderlands of western Thailand. Vertebrate Zoology 71: 763-779. https://doi.org/10.3897/vz.71.e73529
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Abstract
The integrated results of morphological and molecular phylogenetic analyses confirmed the new species status of a recently discovered population of Ansonia from Suan Phueng District, Ratchaburi Province, Thailand. Ansonia karen sp. nov. is separated from all other species of Ansonia by a unique combination of mensural, discrete morphological, and color pattern characteristics and is the sister species of A. thinthinae from Tanintharyi Division, Myanmar. This discovery fills a geographic hiatus of 350 km between it and A. kraensis from Ranong Province, Thailand. Ansonia karen sp. nov. is the newest member of a long list of range-restricted endemics having been recently discovered in the northern Tenasserim Mountain region of western Thailand and continues to underscore the unexplored nature of this region and its need for conservation.
Ansonia karen sp. nov., Molecular phylogenetics, Ratchaburi Province, Southeast Asia, Tenasserim Mountains, Thai-Malay Peninsula, toads
Stream toads of the genus Ansonia Stoliczka, 1870 comprise a distinctive clade of small anurans with relatively flat bodies and heads, and long thin limbs with slender bulbous digits that are adaptations for their scansorial, lotic life style. Species of Ansonia are generally restricted to rocky fast-flowing streams along the mountainous and hilly border regions of southeastern Myanmar and western and southern Thailand, southward through the Thai-Malay Peninsula to Sumatra, Borneo, and the Philippines (Grismer et al. 2016;
The general life history of their tadpoles—adhering themselves to the surfaces of rocks beneath fast-flowing water or in the spray zones of cascades—restricts the distribution of Ansonia to riverine habitats. As such, range-restricted endemism is characteristic of many species in this genus and those with widespread distributions from multiple localities are likely to be species complexes (e.g.
This is the case for a Thai-Burmese clade of nine species of Ansonia distributed from eastern Myanmar to western and southern Thailand where each is known from only its type locality or another locality close by with confluent riverine systems (Fig.
Specimens were collected in Suan Phueng District, Ratchaburi Province, Thailand by Parinya Pawangkhanant, Platon V. Yushchenko, Mali Naiduangchan, Chatmongkon Suwannapoom, and Nikolay A. Poyarkov during several field surveys from 2016 to 2019. The location of the surveyed locality and the distribution of the Thai-Burmese clade of Ansonia are shown in Figure
Specimen collection and animal use protocols were approved by the Institutional Ethical Committee of Animal Experimentation of the University of Phayao, Phayao, Thailand (certificate number UP-AE61-01-04-022, issued to Chatmongkon Suwannapoom) and were strictly complacent with the ethical conditions of the Thailand Animal Welfare Act. Field work, including collection of animals in the field and specimen exportation, was authorized by the Institute of Animals for Scientific Purpose Development (IAD), Bangkok, Thailand (permit numbers U1-01205-2558 and UP-AE59-01-04-0022, issued to Chatmongkon Suwannapoom).
Observations on color pattern were based on the examination of specimens in life as well as digital images of living and euthanized specimens prior to preservation. Measurements were recorded with a Mitutoyo dial caliper under a Nikon SMZ 1500 dissecting microscope to the nearest 0.01 mm. Measurements of adult specimens generally following
Raw mensural data from the type series of Ansonia karen sp. nov. Abbreviations are listed in the Materials and methods; an asterisk (*) marks the holotype specimen.
males | SVL | HL | HW | SW | SL | DNE | IND | IOD | ED | UEW | VTD | TD | T-ED | FAL | HAL | 1FL | THL | TIL | FL | 1TL | IMTL | OMTL | 3FDW | HLL | FLL |
ZMMU A-7605* | 24.9 | 8.3 | 7.5 | 3.8 | 2.9 | 1.9 | 1.8 | 2.5 | 2.7 | 1.9 | 1.4 | 1.1 | 0.3 | 13.1 | 7.4 | 1.3 | 11.4 | 11.8 | 9.9 | 1.8 | 1.8 | 1.3 | 0.7 | 35.6 | 17.3 |
ZMMU A-7606 | 25.6 | 8.4 | 7.7 | 3.9 | 2.7 | 1.5 | 1.9 | 2.6 | 2.7 | 1.8 | 1.3 | 0.9 | 0.4 | 13.1 | 6.6 | 1.3 | 10.2 | 11.4 | 9.8 | 1.5 | 1.6 | 1.2 | 0.5 | 34.9 | 16.8 |
ZMMU A-7607 | 23.9 | 6.9 | 7.2 | 3.7 | 2.9 | 1.8 | 1.7 | 2.9 | 2.8 | 2.1 | 1.4 | 1.3 | 0.0 | 12.5 | 6.6 | 1.6 | 10.3 | 11.1 | 8.9 | 1.4 | 1.0 | 0.8 | 0.4 | 33.9 | 16.2 |
ZMMU A-7608 | 23.2 | 7.6 | 7.8 | 4.4 | 3.0 | 1.7 | 1.8 | 2.5 | 3.3 | 2.5 | 1.5 | 1.2 | 0.4 | 12.7 | 6.7 | 1.4 | 10.0 | 10.8 | 8.9 | 1.5 | 1.6 | 1.2 | 0.7 | 33.1 | 16.7 |
ZMMU A-7609 | 23.5 | 7.4 | 7.7 | 4.4 | 3.2 | 2.2 | 2.0 | 2.9 | 2.8 | 2.1 | 1.4 | 1.4 | 0.6 | 12.6 | 6.6 | 1.4 | 11.7 | 11.2 | 9.4 | 2.0 | 1.6 | 1.0 | 0.6 | 37.7 | 19.5 |
ZMMU A-7610 | 23.7 | 7.4 | 7.6 | 4.1 | 3.2 | 2.1 | 2.1 | 2.8 | 3.0 | 2.0 | 1.2 | 1.6 | 0.3 | 12.6 | 6.4 | 1.4 | 10.4 | 11.4 | 9.6 | 1.7 | 1.4 | 1.2 | 0.6 | 35.9 | 19.1 |
ZMMU A-7611 | 24.7 | 7.4 | 7.7 | 4.3 | 3.5 | 2.0 | 2.2 | 2.9 | 3.2 | 2.1 | 1.4 | 1.4 | 0.4 | 12.6 | 6.7 | 1.3 | 10.8 | 12.0 | 9.8 | 1.7 | 1.7 | 1.2 | 0.6 | 36.8 | 18.1 |
ZMMU A-7612 | 24.8 | 7.5 | 7.4 | 4.6 | 3.3 | 2.0 | 2.4 | 2.9 | 3.1 | 2.3 | 1.3 | 1.3 | 0.3 | 12.8 | 6.8 | 1.3 | 11.7 | 11.8 | 10.2 | 1.8 | 1.7 | 1.0 | 0.5 | 37.8 | 18.0 |
ZMMU A-7613 | 25.4 | 7.9 | 10.0 | 4.5 | 3.7 | 2.2 | 2.3 | 2.9 | 3.1 | 2.3 | 1.1 | 1.4 | 0.7 | 13.3 | 7.0 | 1.4 | 11.2 | 11.8 | 9.9 | 1.7 | 1.6 | 0.9 | 0.6 | 35.8 | 19.8 |
AUP-00661 | 24.4 | 8.0 | 7.5 | 3.8 | 3.1 | 1.5 | 1.9 | 2.4 | 2.6 | 1.9 | 1.4 | 1.0 | 0.3 | 13.2 | 6.5 | 1.3 | 11.4 | 12.1 | 9.8 | 1.8 | 1.8 | 1.2 | 0.5 | 34.8 | 17.4 |
AUP-00662 | 24.6 | 8.1 | 7.7 | 3.7 | 2.9 | 1.6 | 1.9 | 2.4 | 2.6 | 1.8 | 1.3 | 1.0 | 0.3 | 13.1 | 6.5 | 1.3 | 11.1 | 12.0 | 9.7 | 1.7 | 1.8 | 1.2 | 0.5 | 34.2 | 17.4 |
females | SVL | HL | HW | SW | SL | DNE | IND | IOD | ED | UEW | VTD | TD | T-ED | FAL | HAL | 1FL | THL | TIL | FL | 1TL | IMTL | OMTL | 3FDW | HLL | FLL |
AUP-00663 | 28.9 | 9.2 | 8.7 | 4.4 | 3.5 | 2.3 | 2.2 | 2.8 | 2.9 | 2.4 | 1.5 | 1.4 | 0.4 | 14.3 | 8.0 | 2.1 | 13.4 | 14.1 | 11.6 | 1.9 | 2.4 | 1.4 | 0.9 | 43.6 | 21.8 |
AUP-00664 | 29.2 | 9.1 | 8.2 | 4.5 | 3.6 | 2.1 | 2.5 | 2.8 | 2.9 | 2.4 | 1,51 | 1.4 | 0.5 | 14.4 | 7.5 | 2.1 | 14.2 | 13.7 | 11.5 | 1.9 | 2.4 | 1.3 | 0.9 | 44.7 | 21.2 |
ZMMU A-7614 | 26.2 | 8.3 | 7.9 | 4.0 | 3.3 | 2.0 | 2.1 | 3.0 | 3.2 | 2.4 | 1.4 | 1.4 | 0.7 | 13.7 | 7.3 | 1.3 | 12.0 | 12.2 | 10.2 | 1.7 | 2.1 | 1.4 | 0.7 | 39.2 | 19.1 |
ZMMU A-7615 | 27.9 | 8.5 | 8.3 | 4.7 | 3.1 | 2.1 | 2.1 | 3.2 | 3.2 | 2.8 | 1.6 | 1.4 | 0.5 | 14.3 | 7.1 | 2.9 | 12.7 | 13.0 | 11.6 | 1.9 | 2.0 | 1.3 | 0.8 | 43.5 | 21.8 |
AUP-00665 | 28.8 | 8.9 | 8.1 | 4.2 | 3.5 | 2.3 | 2.1 | 2.6 | 2.8 | 2.3 | 1.5 | 1.3 | 0.4 | 14.0 | 7.0 | 2.1 | 13.1 | 13.1 | 11.5 | 1.8 | 2.4 | 1.4 | 0.9 | 44.1 | 20.5 |
Measurements on a single tadpole specimen AUP-02091 followed
The morphospatial clustering among sampled individuals from a selected subset of species and characters for which there was full coverage for each species were visualized using principal component analysis (PCA) from the ADEGENET package in R (
Two-sample t-tests of the all the scaled mensural characters were used to search for statistically significant mean morphometric differences between the new Thai population and its sister species, A. thinthinae (see below). Characters were subjected to an F-test to test for homogeneity of variances. Those with unequal variances were subjected to a Welch’s t-test and those with equal variances were subjected to a Student t-test. All statistical analyses were performed in R [v3.4.3]. Raw and adjusted data are presented in Table S1.
For the molecular phylogenetic analyses, we extracted the total genomic DNA from ethanol-preserved femoral muscle tissue of six specimens of the new Thai population using standard phenol-chloroform-proteinase K extraction procedures with consequent isopropanol precipitation, for a final concentration of about 1 mg/ml (protocols followed
We amplified mtDNA fragments covering partial 16S rRNA gene sequences to obtain a 560 bp-length continuous fragment per specimen. The 16S rRNA gene has widely been applied in biodiversity surveys in amphibians (
PCR products were loaded onto 1.5% agarose gels in the presence of ethidium bromide and visualized in agarose electrophoresis. When distinct bands were produced, we purified the PCR products using 2 μl of a 1:4 dilution of ExoSapIt (Amersham) per 5 μl of PCR product prior to cycle sequencing. A 10 μl sequencing reaction included 2 μL of template, 2.5 μl of sequencing buffer, 0.8 μl of 10 pMol primer, 0.4 μl of BigDye Terminator version 3.1 Sequencing Standard (Applied Biosystems) and 4.2 μl of water. The cyclesequencing used 35 cycles of 10 sec at 96°C, 10 sec at 50°C and 4 min at 60°C. We purified the cyclesequencing products by ethanol precipitation. We carried out sequence data collection and visualization on an ABI 3730xl Automated Sequencer (Applied Biosystems).
Ingroup samples consisted of 128 individuals representing 32 nominal species and included three of the six samples from the new Thai population. Outgroups used to root the tree were Rentapia hosii (Boulenger), Pelophryne brevipes (Peters), P. misera (Mocquard), and P. signata (Boulenger) based in part on the phylogenetic results of
t-value | p-value | test | |
HLL | –2.9397 | 0.02401 | Welch t-test |
SL | –5.0071 | 0.00187 | Welch t-test |
EL | –7.3776 | 0.00022 | Welch t-test |
HTD | –3.9494 | 0.00363 | Welch t-test |
HW | –8.1595 | 7.84E-05 | Welch t-test |
IND | –3.244 | 0.003133 | Student t-test |
IOD | –3.9681 | 0.00656 | Welch t-test |
TIL | –10.845 | 1.49E-06 | Welch t-test |
FLL | –7.8502 | 3.65E-05 | Welch t-test |
Maximum Likelihood (ML) and Bayesian Inference (BI) were used to estimate phylogenetic trees. Best-fit models of evolution were determined in IQ-TREE (
Stationarity was checked with Tracer v1.6 (
The ML and BI analyses recovered nearly identical trees (Fig.
A. Majority-rule consensus tree from 1000 ML bootstrap pseudoreplicates of Ansonia. Phylogeny is based on 2467 bp of concatenated 12S and 16S ribosomal DNA with UFB and BPP support values, respectively, listed at the nodes. Scale bar denotes substitutions site. B. PCA of Ansonia karen sp. nov. and A. thinthinae based on the adjusted mensural characters. C. DAPC of Ansonia karen sp. nov. and A. thinthinae based on the adjusted mensural characters. Photo showing an adult male of Ansonia karen sp. nov. in life by N. A. Poyarkov.
The new Thai population from Suan Phueng and its sister species Ansonia thinthinae have statistically different head, body, and limb proportions (Tables
Summary statistics of the adjusted mensural characters used in the statistical analyses of Ansonia karen sp. nov. and A. thinthinae. Abbreviations are listed in the Material and methods.
A. karen sp. nov. (n=6) | HL | HW | SL | EL | TD | IND | IOD | TIL | FL |
mean | 1.943 | 1.853 | 1.052 | 0.762 | 0.224 | 0.756 | 0.960 | 2.346 | 2.164 |
± sd | 0.034 | 0.041 | 0.055 | 0.072 | 0.081 | 0.104 | 0.063 | 0.028 | 0.038 |
range | 1.907–1.987 | 1.804–1.929 | 0.967–1.112 | 0.672–0.850 | 0.105–0.310 | 0.585–0.851 | 0.847–1.031 | 2.312–2.384 | 2.113–2.212 |
1.987 | 1.929 | 1.112 | 0.850 | 0.310 | 0.851 | 1.031 | 2.384 | 2.212 | |
A. thinthinae (n=24) | |||||||||
mean | 1.983 | 1.995 | 1.167 | 0.986 | 0.369 | 0.853 | 1.066 | 2.486 | 2.298 |
± sd | 0.029 | 0.053 | 0.049 | 0.063 | 0.093 | 0.052 | 0.047 | 0.050 | 0.049 |
range | 1.907–2.030 | 1.804–2.068 | 1.041–1.263 | 0.809–1.108 | 0.198–0.569 | 0.723–0.946 | 0.957–1.161 | 2.312–2.557 | 2.173–2.367 |
Summary statistics and principal component analysis scores for the mensural characters of Ansonia karen sp. nov. and A. thinthinae. Abbreviations are listed in the Materials and methods.
PC1 | PC2 | PC3 | PC4 | PC5 | PC6 | PC7 | PC8 | PC9 | |
Standard deviation | 2.39726 | 0.96600 | 0.89174 | 0.83157 | 0.57186 | 0.47365 | 0.37752 | 0.32949 | 0.17559 |
Proportion of variance | 0.63854 | 0.10368 | 0.08836 | 0.07683 | 0.03634 | 0.02493 | 0.01584 | 0.01206 | 0.00343 |
Cumulative proportion | 0.63854 | 0.74222 | 0.83058 | 0.90741 | 0.94375 | 0.96868 | 0.98451 | 0.99657 | 1 |
Eigenvalue | 5.74685 | 0.93316 | 0.79520 | 0.69150 | 0.32702 | 0.22434 | 0.14252 | 0.10856 | 0.03083 |
HIL | 0.27098 | 0.54668 | –0.48265 | 0.10878 | –0.53108 | 0.16594 | –0.09269 | 0.22918 | –0.11062 |
SL | 0.33941 | –0.03475 | –0.41842 | –0.11058 | 0.72617 | 0.08739 | –0.11690 | 0.33045 | –0.19611 |
ED | 0.34608 | –0.14423 | 0.01457 | 0.50058 | –0.03803 | –0.62922 | –0.45158 | –0.05594 | 0.06492 |
HTD | 0.29530 | 0.23246 | 0.58207 | –0.45619 | –0.08608 | –0.26407 | –0.05060 | 0.35025 | –0.33087 |
HW | 0.38077 | 0.19814 | 0.02006 | 0.16603 | 0.12146 | –0.24659 | 0.79279 | –0.04052 | 0.28647 |
IND | 0.24973 | –0.73749 | –0.24304 | –0.17910 | –0.39792 | –0.03709 | 0.25438 | 0.12371 | –0.25072 |
IOD | 0.34435 | 0.06183 | –0.18036 | –0.58885 | –0.02297 | –0.06361 | –0.20669 | –0.60330 | 0.29507 |
TIL | 0.37290 | 0.01362 | 0.26001 | 0.31988 | 0.05980 | 0.42742 | 0.02970 | –0.48613 | –0.51707 |
FL | 0.37339 | –0.19475 | 0.30554 | 0.09243 | –0.06762 | 0.50026 | –0.18555 | 0.30861 | 0.57988 |
ZMMU A-7605 (field number NAP-06631), an adult male collected on 8 November 2016 at a forest stream within the montane evergreen forest of Khao Laem Mt., Suan Phueng District, Ratchaburi Province, Thailand (13.54732N, 099.20394E; 715 m a.s.l. in elevation), by P. Pawangkhanant, C. Suwannapoom and N. A. Poyarkov.
ZMMU A-7606 (field number NAP-06630), an adult male with same collection information as holotype; ZMMU A-7607 (no field number) and ZMMU A-7608 (field number AUP-00349), two adult males collected on 15 June 2018 at same locality as holotype by P. Pawangkhanant, C. Suwannapoom and M. Naiduangchan; ZMMU A-7609–A-7614 (field numbers NAP-10193–NAP-10198), five adult males and an adult female collected on 18 June 2019 at a forest stream within the montane evergreen forest on the northern slope of Khao Laem Mt., Suan Phueng District, Ratchaburi Province, Thailand (N 13.54581, E 099.20368; 758 m a.s.l. in elevation), by P. Yushchenko and M. Naiduangchan; AUP-00661–00665, two adult males and three adult females collected on 15 June 2019 at same locality as holotype by P. Pawangkhanant and M. Naiduangchan; and ZMMU A-7615 (field number NAP-09901), an adult female collected on 4 October 2019 at same locality as holotype by P. Pawangkhanant.
Ansonia karen sp. nov. is recognized as a member of the genus Ansonia based on the results of the molecular phylogenetic analyses that recover it as the sister species of A. thinthinae (Fig.
Adult male, SVL 24.9 mm (Figs
Forelimbs and fingers long and slender (HAL/SVL=0.30; FLL/SVL=0.69); finger length from shortest to longest: I<II<IV<III; basal webbing not extending beyond proximal subarticular tubercle (Fig.
Top of head black (Fig.
Holotype of Ansonia karen sp. nov. (ZMMU A-7605) in life from Suan Phueng District, Ratchaburi Province, western Thailand. A. Dorsal view. B. Ventral view. C. Right lateral view of head. D. Dorsal view of head. E. Ventral view of left hand. F. Ventral view of left foot. Photos by N. A. Poyarkov.
After five years of storage in ethanol, the warm reddish, yellowish and orange tints have significantly faded, the specimen looks dark greyish-brown; however all major features of coloration pattern are still well-discernable.
Raw and adjusted mensural data of the type series are presented in Tables
Description based on AUP-02091 at
In life (Fig.
Ansonia karen sp. nov. is currently known only from the type locality and nearby locality in same forest stream in the environs of Khao Laem Mountain, in Suan Phueng District of Ratchaburi Province in western Thailand, less than 2.0 km from the international Thai–Myanmar border (Fig.
The new species inhabits a polydominant montane tropical evergreen forest on Khao Laem Mountain at elevations from ca. 700 to 750 m a.s.l., where the adult specimens were observed at night perched on leaves or stones (Fig.
Natural history of Ansonia karen sp. nov. A. Breeding habitat of the new species Ansonia karen sp. nov. in Suan Phueng District, Ratchaburi Province, western Thailand. B. Female of the new species in situ (not collected). C. Male of the new species in situ (not collected). D. Tadpole at
The species of amphibians and reptiles recorded in sympatry with the new species at the type locality include: Leptobrachium tenasserimense Pawangkhanant, Poyarkov, Duong, Naiduangchan & Suwannapoom, L. smithi Matsui, Xenophrys cf. major (Boulenger), Leptobrachella melanoleuca (Matsui), L. fuliginosa (Matsui), Amolops panhai Matsui & Nabhitabhata, Alcalus tasanae (Smith), Limnonectes jarujini Matsui, Panha, Khonsue & Kuraishi, L. doriae (Boulenger), L. macrognathus (Boulenger), M. berdmorei (Blyth), Acanthosaura crucigera Boulenger, Pseudoxenodon macrops (Blyth), Trimeresurus popeiorum Smith, and Rhabdophis chrysargos (Schlegel).
The specific name “karen” is given as a noun in apposition and refers to the name of the Karen people. Originally inhabiting wide areas in southern and southeastern Myanmar, many Karen have migrated to Thailand, having settled mostly on the Thailand–Myanmar border, including the Suan Phueng District, the type locality of the new species, due to the political turmoil during the end of XX – beginning of XXI centuries. We received significant help and assistance from the local Karen community in Suan Phueng during our field surveys and want to thank them for their permanent support. NAP also thanks Karen Sarkisian for his support and encouragement.
Ansonia karen sp. nov. is most closely related to A. thinthinae but differs from it by being smaller, more squat and having statistically significant differences in head and limb proportions (see above and Table
Morphological and color pattern characters of the species of the Thai-Burmese clade of Ansonia. Bold character states are those that discretely separate A. karen sp. nov. from some or all the other species of the clade.
Species | karen sp. nov | inthanon | khaochangensis | kraensis | kyaiktiyoensis | pilokensis | phukentensis | siamensis | thinthinae |
---|---|---|---|---|---|---|---|---|---|
SVL (Female) | 26.2–29.2 | 23.3–25.2 | 34–35.3 | 24.0–27.9 | 24 | 24.7–25.4 | 28.1–30.5 | 32.2–34.6 | 31.8 |
Maximum SVL (Male) | 23.2–25.4 | 22.9–23.3 | 31.9–32 | 19.9–22.3 | 24 | 19.9–23.9 | 23.1–25.4 | 25.5–27.9 | 22.1–28.1 |
Snout projecting beyond lower jaw (1) or not (0) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Tympanum visible (1) or not (0) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 or 1 | 1 |
Light coloured rictal tubercle(s) at the corner of the jaw present (1) or not (0) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Interorbital tubercle ridges present (1) or not (0) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Opening of vocal sac on right (1) or left (0) | 1 | 1 | 1 | 0 | / | 0 | 1 | 0 or 1 | 0 or 1 |
Finger tips rounded or forming small discs (1) or expanded and spatulate (0) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Toe tips rounded or forming small discs (1) or expanded and spatulate (0) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
1st finger reaching the disc of the 2nd (1) or not (0) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
No. of fingers with nuptial pads | 1 | 1 | 0 | 1 | 0 | 2 | 2 | 1 | 1 + 2 |
No. of free phalanges of V toe | 0.5 | 0.5–1 | 2 | 0.5 | 1.5 | 0.5 | 0.5 | 1 | 0.5 |
No. of free phalanges of IV toe | 2.5 | 2.75 | 3–3.5 | 0.5–2.0 | 3 | 2.75–3 | 3 | 2 | 2.75–3 |
No. of free phalanges of III toe | 0.5 | 0.5–2.66 | 2 | 0.5–2.33 | 1.5–3 | 0.5–2 | 1 | 1 | 0.5–2 |
No. of free phalanges of II toe | 0.5 | 0.5–2 | 1–1.5 | 0.5–2.0 | 0.5–1.5 | 0.5–1 | 0.5 | 1 | 0.5–1 |
No. of free phalanges of I toe | 0.5 | 0.5–1 | 0.5 | 0.5–1.0 | 0.5 | 0.5 | 0.5 | 1 | 0.5 |
Tarsal ridge present (1) or not (0) | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
Inner metatarsal tubercle present (1) or not (0) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Outer metatarsal tubercle present (1) or not (0) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Submandibular tubercles in males present (1) or not (0) | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 0 | 1 |
Dorsal tubercles present (1) or not (0) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 |
Dorsolateral row of enlarged tubercles present (1) or not (0) | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 1 |
Rows of tubercles on back (1) or not (0) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Oblique flap of skin on each side of vent (1) or not (0) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | / |
Abdomen coarsely granular (1), finely granular (2), or tuberculate (0) | 1 | 1 | 1 | 1 | 1 | 1 | 2 | 2 | 1 |
Color or iris | Yellowish–gold | gold | black | Gold | Yellowish–gold | Gold | Gold | / | Yellow |
Gular spotting present (1) or not (0) | 0 | 1 | 0 | 0 | 0 | 1 | 0 | 1 | 1 |
Wide, light patch below eye (1) or not (0) | 1 | 0 | 0 | 0–1 | 0 | 1 | 1 | 0 | 1 |
White postorbital patch present (1) or not (0) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Light spot between the scapulae present (1) or not (0) | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 0 | 1 |
Light crossbar on hind limbs present (1) or not (0) | 1, irregular in shape | 1 | 0 | 1 | 1 | 1 (faint) | 1 | 1 | 1 |
Vertebral stripe present (1) or not (0) | 0 | 0 | 0 | 0 | 0 | 1 | 0–1 | 0 | 0 |
Discrete white or bright yellow spots along the underside of lower jaw large (2), small (1) or absent (0) | 2 | 2 | 0 | 1 | 2 | 2 | 2 | 2 | 2 |
The genus Ansonia was hypothesized to have evolved and diversified in Borneo before independently dispersing to the Philippines, Sumatra, and twice onto the Thai-Malay Peninsula (Grismer et al. 2016). The first colonization of the Thai-Malay Peninsula ~11.1 million years ago (mya), ultimately resulted in the evolution of a clade that currently contains at least 17 species, including the new species Ansonia karen sp. nov. Diversification of this clade at its point of origin in Peninsular Malaysia was followed by a northward expansion across the Kangar-Pattani Line between Thailand and Peninsular Malaysia at approximately 6.7 mya, giving rise to the Thai-Burmese clade and further diversification into at least eight species after crossing the Isthmus of Kra farther north at approximately 5.5 mya (Grismer et al. 2016).
Ansonia karen sp. nov. is the newest member of the Thai-Burmese species which is confined to the rugged mountainous regions west of the Chao Praya Basin of Thailand. The close geographic proximity of some of its non-sister species (e.g. A. pilokensis, A. khaochangensis, and A. phuketensis) and the discordance between the phylogenetic relationships and geographic distribution of the other Ansonia species, is indicative of the complicated biogeographic nature concerning the origin of these range-restricted endemics. The discovery of Ansonia karen sp. nov. in this section of the Tenasserim Mountains is more of an expectation than a surprise in that it fills a notable hiatus of 350 km between A. thinthinae from the Tanintharyi Nature Reserve, Tanintharyi Division, Myanmar and A. kraensis from the Punyaban Waterfall, Ranong Province, Thailand (see Fig.
The northern Tenasserim Mountain region is notable for the recent discoveries of endemic amphibians and reptiles (
We would like to thank the Laboratory Animal Research Center, University of Phayao and The Institute of Animal for Scientific Purposes Development (IAD), Thailand for permission to do field work. We also want to thank the Rabbit in the Moon foundation for help during the field work, and especially to Charnchai Bindusen and Juthamas Wangaryattawanich for organizing and supporting our fieldwork; and to Krarok Wohde, Torn Wohde, Jo Wohde, Maiday Ta-Au for assistance in the field; we thank Kanokwan Yimyoo for constant support and Pattarawhich Dawwrueng, Thiti Ruengsuwan, Kawin Jiaranaisakul, Akkrachai Aksornneam for help during the field work. NAP also thanks Karen Sarkisian for his support and encouragement; NAP is grateful to Dr. Valentina F. Orlova and Roman A. Nazarov (ZMMU) for help during the work in collection under their care; NAP thanks the members of MSU HerpLab including Vladislav A. Gorin, Evgeniya N. Solovyeva, Andrei M. Bragin, Sabira S. Idiatullina, Alexey Trofimets, and Anna S. Dubrovskaya for support and assistance. We express our sincere gratitude to two anonymous reviewers for their useful suggestions on an earlier version of the manuscript. Fieldwork, specimen collection, morphological examination, molecular phylogenetic analyses and data analyses for this paper were conducted with the financial support of the Russian Science Foundation (RSF grant No. 19-14-00050 to Nikolay A. Poyarkov); specimen collection and data analysis were also partially supported by the grants of the Unit of Excellence 2022 on Biodiversity and Natural Resources Management, University of Phayao (No. FF65-UoE003, specimen collection) and Thailand Research Fund (DBG6180001; specimen collection, data analysis) to Chatmongkon Suwannapoom.
Data type: .docx
Explanation note: Adjusted and raw mensural data from males of the type series of Ansonia karen sp. nov. and A. thinthinae used in the statistical analyses. Abbreviations are in the Materials and methods.