Research Article |
Corresponding author: L. Lee Grismer ( lgrismer@lasierra.edu ) Corresponding author: Nikolay A. Poyarkov ( n.poyarkov@gmail.com ) Academic editor: Uwe Fritz
© 2021 Anh The Nguyen, Tang Van Duong, L. Lee Grismer, 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:
Nguyen AT, Duong TV, Grismer LL, Poyarkov NA (2021) A new granite cave-dwelling Bent-toed Gecko from Vietnam of the Cyrtodactylus irregularis group (Squamata; Gekkonidae) and a discussion on cave ecomorphology. Vertebrate Zoology 71: 155-174. https://doi.org/10.3897/vz.71.e60225
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An integrative analysis of genetic, morphological, and ecological data recovered a new granite cave-adapted species, Cyrtodactylus raglai sp. nov., from the Song Giang River Valley, Khanh Hoa Province, Vietnam. Cyrtodactylus raglai sp. nov. is nested within one of two major clades within the irregularis species group where it forms a monophyletic group with C. cryptus and its sister species C. kingsadai. It differs from its sister species by an uncorrected pairwise sequence divergence of 16.5% and 16.8% based on the mitochondrial genes NADH dehydrogenase subunit 2 and its flanking tRNAs and the first subunit of cytochrome oxidase c (CO1), respectively. Cyrtodactylus raglai sp. nov. is a narrow-range endemic restricted to a riparian, granite cave microhabitat and its overall morphology bears that of other granite cave-dwelling ecomorphs in the genus. The Song Giang River Valley and its associated waterways are currently threatened by the construction of a hydropower station which will negatively impact the surrounding ecosystem. Urgent field surveys in this region are necessary in order to obtain critical data on its biodiversity and importance to conservation efforts in southern Vietnam.
Ecomorph, Indochina, narrow-range endemic, reptiles, taxonomy
The Cyrtodactylus irregularis group is the largest, most taxonomically diverse species group within the genus. It contains 22 nominal species and at least 11 undescribed species (
Distribution of the species of the Cyrtodactylus irregularis group. Dot in the center of an icon indicates the type locality of a species. The small inset map shows Vietnam and the location of the area of studies detailed in a larger map (red rectangle). For details on species localities see
Morphological data included both meristic and mensural characters. Measurements were taken on the left side of the body when possible to the nearest 0.1 mm by NAP using Mitutoyo dial calipers under a Nikon SMZ 1500 dissecting microscope and follow
Meristic characters evaluated were the number of supralabial scales (SL) counted from the largest scale immediately below the middle of the eyeball to the rostral scale; infralabial scales (IL) counted from the mental to the termination of enlarged scales just after the upturn of the mouth; the number of paravertebral tubercles (PVT) between limb insertions counted in a straight line immediately left of the vertebral column; the number of longitudinal rows of body tubercles (LRT) counted transversely across the center of the dorsum from one ventrolateral fold to the other; the number of longitudinal rows of ventral scales (VS) counted transversely across the center of the abdomen from one ventrolateral fold to the other; the number of expanded subdigital lamellae on the fourth toe (4TL) counted from the base of the first phalanx where it contacts the body of the foot to the claw including the claw sheath (see
Majority-rule consensus tree from 1000 ML bootstrap pseudoreplicates of Cyrtodactylus. Phylogeny is based on 1469 bp of ND2 Black circles represent nodes the UB and BPP support > 90 and 0.90, respectively. Grey circles represent nodes with UB support > 90 only. The white circle represents a node with BPP support > 0.90 only. Nodes lacking circles are unsupported. Scale bar denotes uncorrected pairwise sequence divergence. Species group designations follow
Majority-rule consensus tree from 1000 ML bootstrap pseudoreplicates of the Cyrtodactylus irregularis group. Phylogeny is based on 691 bp of CO1. Black circles represent nodes with UB support > 90. Nodes lacking circles are unsupported. Scale bar denotes uncorrected pairwise sequence divergence. Photograph by Anh The Nguyen.
Color pattern characters evaluated were the nuchal loop being continuous from orbit to orbit across the nape, or separated medially into paravertebral halves, bearing an anterior azygous notch or not, and the shape of its posterior border; presence or absence of a band on the nape; dorsal body bands bearing paired, having paravertebral elements or not; dark dorsal body bands wider than light interspaces, with or without lightened centers, edged with light tubercles or not, irregularly shaped or more regular (straight-edged or even); dark markings present or absent in the dorsal interspaces; top of head bearing combinations of dark, diffuse mottling or dark, distinct blotches overlain with a light-colored reticulating network or not; anterodorsal margin of thighs and brachia whitish due to a lack of dark pigment; light caudal bands bearing dark markings or immaculate; light caudal bands encircling the tail or not; and dark caudal bands wider than light caudal bands.
Analyses of variance (ANOVA) were conducted on selected meristic and mensural characters (see below) with statistically similar variances (i.e. p values ≤ 0.05 in a Levene’s test) to search for the presence of statistically significant mean differences (p < 0.05) among species across a subset of the irregularis group. Character means bearing statistical differences were subjected to a TukeyHSD test to ascertain which species pairs differed significantly from each other for those particular characters. Boxplots were generated in order to visualize the range, mean, median, and degree of differences between pairs of species bearing statistically different mean values. All statistical analyses were performed in R [v3.4.3].
The morphospatial clustering among the sampled individuals from the selected subset of species were visualized using principal component analysis (PCA) from the ADEGENET package in R (
A discriminant analysis of principal components (DAPC) was performed on both data sets. The DAPC places individuals from each predefined population into separate clusters (i.e., plots of points) bearing the smallest within-group variance that produce linear combinations of centroids having the greatest between-group variance (i.e. linear distance;
The type material is deposited in the herpetological collection of the Department of Zoology, Southern Institute of Ecology (
A data set composed of the 310 species of Cyrtodactylus from
Additionally, to compare the newly discovered population of Cyrtodactylus sp. from Khanh Hoa Province with other members of the irregularis species group, we generated a 672 base pair segment of the 5’-end of (CO1) which included 29 sequences of 26 species and compared it with the CO1-barcoding dataset from
Genomic DNA was isolated from liver tissue stored in 95% ethanol using the following DNA extraction protocol. A small amount of liver tissue (about 1–3 mg) was dried and transferred to 500µl of extraction buffer including 1% SDS, 0.4 mg/ml proteinase K, 10mM Tris HCl (pH 8.0), 1mM EDTA, 100mM NaCl, and subsequently incubated at 56 °C for 3 hours, then centrifuged at 12,000 rpm for one minute. The 450 µl of supernatant were transferred into a new 1.5 ml tube, where 50 µl of 3M sodium acetate solution and 500µl of ice-cold isopropanol were added, mixed and refrigerated at -20 °C for 15 minutes, again centrifuged again at 12,000 rpm for one minute, the supernate was discarded, and the DNA sediment was washed with 500 µl of 70% ethanol. After the ethanol was removed, the total DNA was dried at 50 °C for 8 minutes and subsequently resuspended with 50 µl TE.
The ND2 gene, with parts of adjacent tRNAs, was amplified using a double-stranded Polymerase Chain Reaction (PCR) under the following conditions: 1.0 µl genomic DNA (10–30 µg), 1.0 µl light strand primer (concentration 10 µM), 1.0 µl heavy strand primer (concentration 10 µM), 15 µl Master Mix 2x (CWBIO, China), and 12 µl ultra-pure H2O. PCR reactions were executed on Bio-Rad T100™ gradient thermocycler under the following conditions: initial denaturation at 94 °C for 5 min, followed by a second denaturation at 94 °C for 60 s, annealing at 58 °C for 60 s, followed by a cycle extension at 72 °C for 60 s, for 35 cycles with the final extension step 72 °C for 10 min. For amplification of the full ND2 gene with parts of adjacent tRNAs we used the NADH2-Metf6 (5’-AAGCTTTCGGGCCCATACC-3’) and CO1H (5’-AGRGTGCCAATGTCTTTGTGRTT-3’) primers following
We also amplified the 5’-fragment of the CO1 mtDNA gene; the PCR parameters and the amplification protocol and conditions were the same as for the ND2 gene, but the annealing temperature was at 45 °C. Primers used both for PCR and sequencing were the VF1-d (5’-TTCTCAACCAACCACAARGAYATYGG-3’) and the VR1-d (5’-TAGACTTCTGGGTGGCCRAARAAYCA-3’) following
All PCR products were visualized using 1.0 % agarose gel electrophoresis. Successful PCR products were sent to National Key Laboratory of Gene Technology (Institute of Biotechnology, VAST, Hanoi, Vietnam) for PCR purification, cycle sequencing, sequencing purification, and sequencing using the same primers as in the amplification step. Sequences were analyzed from both the 3’ and the 5’ ends separately to confirm congruence between reads. Forward and reverse sequences were uploaded and edited in Geneious 2019.0.4 (https://www.geneious.com). Following sequence editing we aligned the protein-coding region of ND2 and the flanking tRNAs using the MAFTT v7.017 (Katoh and Kuma, 2002) plugin under the default settings in Geneious 2019.0.4 (https://www.geneious.com). Mesquite v3.04 (Maddison and Maddison, 2015) was used to calculate the correct amino-acid reading frame and to confirm the lack of premature stop codons in the ND2 portion of the DNA fragment. The 5’-end partial CO1 sequences were aligned in MAFTT v7.017, and similarly checked for the absence of stop-codons in Mesquite v3.04.
The sequence of ND2 gene and flanking tRNAs fragment and the 5’-end partial sequence of CO1 gene of the newly collected specimen
A Maximum likelihood (ML) analysis for the ND2 data set was implemented using the IQ-TREE webserver (
A Bayesian phylogenetic tree (BI) was estimated using Bayesian Evolutionary Analysis by Sampling Trees (BEAST) version 2.4.6 (
The general lineage concept (GLC:
For the ND2 dataset, the ML and BI analyses recovered trees with very similar topologies, and the ML topology used here (Fig.
The CO1 barcoding data set recovered a polytomy with no backbone support and little resemblance to the ND2 tree (Fig.
Uncorrected pairwise sequence divergence of ND2 and the flanking tRNAs among the individuals of clade 1 of the Cyrtodactylus irregularis species group. Highlighted cells denote sequence divergence of each species from C. raglai sp. nov.
Species | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 |
1. cryptus | 0.00 | ||||||||||
2. culaochamensis | 0.162 | 0.00 | |||||||||
3. kingsadai | 0.152 | 0.150 | 0.00 | ||||||||
4. pseudoquadrivirgatus | 0.164 | 0.094 | 0.143 | 0.00 | |||||||
5. raglai sp. nov. | 0.165 | 0.165 | 0.133 | 0.170 | 0.00 | ||||||
6. sp. HLM0316 Kon Ka Kinh | 0.160 | 0.115 | 0.136 | 0.122 | 0.159 | 0.00 | |||||
7. sp. HLM0354 Kon Tum | 0.157 | 0.082 | 0.153 | 0.087 | 0.169 | 0.122 | 0.00 | ||||
8. sp. HLM0365 Kon Ka Kinh | 0.166 | 0.134 | 0.152 | 0.128 | 0.177 | 0.132 | 0.133 | 0.00 | |||
9. sp. HLM0366 Chu Mom Ray | 0.172 | 0.122 | 0.150 | 0.119 | 0.172 | 0.123 | 0.118 | 0.105 | 0.00 | ||
10. sp. NAP08781 Song Thanh | 0.150 | 0.081 | 0.143 | 0.081 | 0.159 | 0.122 | 0.040 | 0.125 | 0.120 | 0.00 | |
11. taynguyenensis | 0.159 | 0.088 | 0.142 | 0.100 | 0.158 | 0.113 | 0.096 | 0.121 | 0.116 | 0.097 | 0.00 |
The PCA, based on the meristic data set, demonstrated that the new population from Song Giang River Valley clustered separately from its closest relatives and overlapped C. kingsadai, along PC2 (Fig.
A. PCA of the Cyrtodactylus raglai sp. nov, C. cryptus, and C. kingsdai based on meristic characters. B. DAPC of same. C. Histograms of the factor loadings of the characters contributing the most to the variation along PC1 and PC2. D. Boxplot comparisons of meristic characters. Light-blue circles are means and black horizontal bars are medians. Species pairs above the plots are those that differ significantly (p < 0.05) from each other based on the ANOVAs and TukeyHSDs.
Summary statistics and principal component analysis scores for meristic characters of Cyrtodactylus raglai sp. nov., C. cryptus, and C. kingsadai. Abbreviations are listed in the Materials and methods.
PC1 | PC2 | PC3 | PC4 | PC5 | PC6 | |
Standard Deviation | 1.622433547 | 1.25259312 | 0.919763047 | 0.763032664 | 0.520878109 | 0.314996742 |
Proportion of Variance | 0.43872 | 0.2615 | 0.14099 | 0.09704 | 0.04522 | 0.01654 |
Cumulative Proportion | 0.43872 | 0.70021 | 0.84121 | 0.93824 | 0.98346 | 1 |
Eigenvalue | 2.632290614 | 1.568989524 | 0.845964063 | 0.582218847 | 0.271314004 | 0.099222947 |
SL | 0.358949999 | -0.471241487 | –0.267598779 | 0.585203794 | –0.411445547 | –0.256371476 |
IL | 0.123838432 | -0.696295734 | 0.338218543 | –0.001681462 | 0.609470686 | 0.118267351 |
LRT | 0.564321114 | 0.230965469 | –0.030580096 | 0.175925709 | 0.016848143 | 0.772028351 |
VS | 0.32917155 | 0.397242696 | 0.680146485 | 0.313822976 | 0.089154163 | –0.405970153 |
FS | 0.45560393 | –0.211652886 | 0.229149873 | –0.69862878 | –0.445675149 | –0.091705728 |
4TL | 0.470565374 | 0.192769188 | –0.545852602 | -0.200042007 | 0.502393653 | –0.388634814 |
Summary statistics of selected meristic and mensural characters of Cyrtodactylus raglai sp. nov., C. kingsadai, and C. cryptus. Mean values in bold differ significantly from the corresponding mean value in C. raglai sp. nov. (p < 0.05).
Meristic Characters | Cyrtodactylus raglai sp. nov. (n=3) | Cyrtodactylus kingsadai (n=6) | Cyrtodactylus cryptus (n=4) |
---|---|---|---|
supralabials (SL) | |||
Mean | 10.7 | 12.4 | 10.3 |
± 1 SD | 0.58 | 1.42 | 0.50 |
Range | 10 or 11 | 10–14 | 10 or 11 |
infralabials (IL) | |||
Mean | 9.3 | 10.0 | 9.0 |
± 1 SD | 0.58 | 0.89 | 1.55 |
Range | 9 or 10 | 9–11 | 8–10 |
longitudinal rows of tubercles (LRT) | |||
Mean | 14.3 | 19.2 | 19.0 |
± 1 SD | 0.58 | 3.5 | 1.41 |
Range | 14 or 15 | 14–23 | 17–20 |
ventral scales (VS) | |||
Mean | 37.3 | 42.2 | 48.8 |
± 1 SD | 1.53 | 4.00 | 1.23 |
Range | 36–39 | 39–46 | 47–50 |
subdigital lamellae on 4th toe (4TL) | |||
Mean | 21.3 | 22.7 | 22.3 |
± 1 SD | 0.58 | 1.37 | 0.96 |
Range | 20 or 21 | 21–25 | 20–23 |
Adjusted Mensural Characters | |||
head length (HL) | |||
Mean | 3.3 | 3.2 | 3.1 |
± 1 SD | 0.02 | 0.031 | 0.02 |
Range | 3.29–3.34 | 3.21–3.29 | 3.05–3.09 |
head width (HW) | |||
Mean | 2.9 | 2.8 | 2.7 |
± 1 SD | 0.01 | 0.07 | 0.09 |
Range | 2.90–2.91 | 2.72–2.91 | 2.57–2.77 |
head depth (HD) | |||
Mean | 2.3 | 2.3 | 2.2 |
± 1 SD | 0.00 | 0.06 | 0.04 |
Range | 2.31–2.32 | 2.21–2.41 | 2.16–2.27 |
eye diameter (ED) | |||
Mean | 1.9 | 1.8 | 1.6 |
± 1 SD | 0.02 | 0.07 | 0.08 |
Range | 1.88–1.91 | 1.73–1.91 | 1.47–1.67 |
snout length (SNT) | |||
Mean | 2.5 | 2.4 | 2.2 |
± 1 SD | 0.036 | 0.18 | 0.01 |
Range | 2.49–2.56 | 2.13–2.61 | 2.22–2.24 |
The PCA, based on the mensural data set, demonstrated that the Song Giang River Valley population clustered separately from its closest relatives and overlapped with them along PC2 but not PC1 (Fig.
Based on the phylogenetic, PCA, DAPC, and ANOVA analyses and the high degree of uncorrected pairwise sequence divergence between the Song Giang River Valley population and the remaining species in clade 1 (Figs
A. PCA of the Cyrtodactylus raglai sp. nov, C. cryptus, and C. kingsdai based on mensural characters. B. DAPC of same. C. Histograms of the factor loadings of the characters contributing the most to the variation along PC1 and PC2. D. Boxplot comparisons of meristic characters. Light-blue circles are means and black horizontal bars are medians. Species pairs above the plots are those that differ significantly (p < 0.05) from each other based on the ANOVAs and TukeyHSDs. Photographs by Anh The Nguyen.
Summary statistics and principal component analysis scores for mensural characters of Cyrtodactylus raglai sp. nov.,C. cryptus, and C. kingsadai. Abbreviations are listed in the Materials and methods.
PC1 | PC2 | PC3 | PC4 | PC5 | |
Standard Deviation | 1.90913762 | 0.890016517 | 0.538548404 | 0.467906735 | 0.23257913 |
Proportion of Variance | 0.72896 | 0.15843 | 0.05801 | 0.04379 | 0.01082 |
Cumulative Proportion | 0.72896 | 0.88739 | 0.94539 | 0.98918 | 1 |
Eigenvalue | 3.644806451 | 0.792129401 | 0.290034383 | 0.218936713 | 0.054093052 |
HL | –0.50087707 | 0.117559638 | –0.026802327 | 0.458852951 | 0.723904343 |
HW | –0.459584098 | –0.154364348 | –0.808742489 | –0.307413883 | –0.128009361 |
HD | –0.422351581 | –0.518980378 | 0.513977677 | –0.518283228 | 0.139599258 |
ED | –0.49614577 | –0.095133377 | 0.203741279 | 0.525612741 | –0.653459833 |
SE | –0.336694424 | 0.827018977 | 0.198830734 | –0.387381487 | –0.114360833 |
Adult male,
Two adult females,
Cyrtodactylus raglai sp. nov. can be separated from all other species of clade1 of the C. irregularis group by having 10 or 11 supralabials; nine or 10 infralabials; 44–47 paravertebral tubercles; 14 or 15 rows of longitudinally arranged tubercles; 36–39 ventrals; 8–10 expanded subdigital lamellae, 12 or 13 unexpanded subdigital lamellae, and 21–22 total subdigital lamellae on the fourth toe; 18 or 19 enlarged femorals; 12 enlarged precloacals; four rows of enlarged post-precloacals; three postcloacal tubercles in males; five precloacal pores in the male; no pitted precloacal scales in females; enlarged femorals and enlarged precloacals not continuous; proximal femorals less than one-half size of distal femorals; enlarged subcaudals; maximum SVL 111.7 mm; small, irregularly shaped dark blotches on top of head; and four irregularly shaped body bands edged with white tubercles wider than the interspaces (Tables
Diagnostic character states among the nominal species of clade 1 of the Cyrtodactylus irregularis group. / = data unavailable.
Cyrtodactylus raglai sp. nov. | Cyrtodactylus cryptus | Cyrtodactylus culaochamensis | Cyrtodactylus kingsadai | Cyrtodactylus pseudoquadrivirgatus | Cyrtodactylus taynguyenensis | |
Maximum SVL (mm) | 111.7 | 90.8 | 79.8 | 94.0 | 83.3 | 104.1 |
Ventral scales | 36–39 | 47–50 | 45–50 | 39–46 | 41–57 | 42–49 |
Enlarged femoral scales | 18 or 19 | / | / | 18–24 | / | 22–26 |
Femoral pores | 0 | / | 0–7 | 0 | 0 | |
Precloacal pores (males) | 5 | 9–11 | 7 or 8 | 7–9 | 6 | 6 |
Precloacal pits (females) | 0 | 0 | 4–8 | 5–10 | 0 | |
4th toe lamellae | 21 or 22 | 20–23 | 20–23 | 21–25 | 16–25 | 17–21 |
Enlarged subcaudals | yes | no | yes | yes | no | no |
Dorsal bands | irregular | irregular | paired-paravertebral | irregular | irregular | irregular to blotched |
Meristic, mensural (mm), discrete morphological, and color pattern data from the type series of Cyrtodactylus raglai sp. nov. Abbreviations are listed in the Materials and methods.
Scale characters |
|
|
|
---|---|---|---|
Supralabials (SL) | 10 | 11 | 11 |
Infralabials (IL) | 9 | 10 | 9 |
Body tubercles low, weakly keeled | yes | yes | yes |
Body tubercles raised, moderately to strongly keeled | no | no | no |
Paravertebral tubercles (PVT) | 46 | 47 | 44 |
Longitudinal rows of body tubercles (LRT) | 14 | 14 | 15 |
Tubercles extend beyond base of tail | yes | yes | yes |
Ventral scales (VS) | 36 | 39 | 37 |
Expanded subdigital lamellae on 4th toe (TLE) | 10 | 9 | 8 |
Unmodified subdigital lamellae on 4th toe (TLU) | 12 | 12 | 13 |
Total subdigital lamellae on 4th toe (TTL) | 22 | 21 | 21 |
Enlarged femoral scales (R/L) | 10/9 | 9/9 | 10/9 |
Total femoral scales (FS) | 19 | 18 | 19 |
Femoral pores (R/L) | 0 | 0 | 0 |
Total femoral pores in males | 0 | 0 | 0 |
Enlarged precolacal scales (PS) | 12 | 12 | 12 |
Precloacal pores (PP) | 5 | 0 | 0 |
Post-precloacal scale rows (PPS) | 4 | 4 | 4 |
Enlarged femoral and precloacal scales continuous | no | no | no |
Pore-bearing femoral and precloacal scales continuous | no | no | no |
Enlarged proximal femoral scales ~1/2 size of distal femorals | yes | yes | yes |
Post-cloacal tubercles (PCT) | 3 | 3 | 3 |
Medial subcaudals 2 or 3 times wider than long | yes | yes | yes |
Medial subcaudals extend up onto lateral surface of tail | no | no | no |
Color pattern characters | |||
Nuchal loop divided medially | no | no | no |
2 posterior projections from nuchal loop | no | no | no |
Nuchal loop with anterior azygous notch | no | no | no |
Posterior border of nuchal loop | jagged | jagged | jagged |
Band on nape | no | no | no |
Dorsal banding with divided paravertebral elements | no | no | no |
Number of body bands (not including nuchal loop) | 4 | 4 | 4 |
Dorsal body bands wider than interspaces | yes | yes | yes |
Dorsal body bands with lightened centers | vertebrally | vertebrally | vertebrally |
Dorsal bands edged with white tubercles | yes | yes | yes |
Shape of dorsal bands | irregular | irregular | irregular |
Dark markings in dorsal interspaces | yes | yes | yes |
Top of head diffusely mottled, blotched, or patternless | blotched | blotched | blotched |
Well-defined, light-colored reticulum on top of head | no | no | no |
Anterodorsal margin of thighs darkly pigmented | no | no | no |
Anterodorsal margin of brachia darkly pigmented | no | no | no |
White caudal bands with dark markings | yes | yes | yes |
White caudal bands encircle tail | no | no | no |
Number of light caudal bands | 7 | 9 | 8 |
Number of dark caudal bands | 8 | 10 | 8 |
Dark caudal bands wider than light caudal bands | yes | yes | yes |
SVL | 95.0 | 111.7 | 87.5 |
TL | 119.0 | 135.0 | 113.4 |
TW | 9.0 | 9.8 | 5.8 |
FL | 15.5 | 18.4 | 14.2 |
FLW | 5.3 | 7.6 | 5.1 |
TBL | 19.0 | 21.5 | 16.7 |
HDW | 9.8 | 12.25 | 9.1 |
AG | 41.0 | 46.0 | 39.7 |
PW | 11.1 | 14.5 | 10.4 |
PH | 8.6 | 11.5 | 8.1 |
HL | 26.2 | 31.0 | 26.0 |
HW | 17.6 | 21.8 | 15.4 |
HD | 10.0 | 11.0 | 9.5 |
ED | 6.5 | 7.8 | 5.6 |
EE | 7.2 | 8.8 | 5.9 |
SNT | 11.7 | 14.5 | 11.6 |
EN | 9.2 | 11.5 | 8.3 |
IO | 3.6 | 4.3 | 3.3 |
EL | 3.0 | 3.4 | 3.0 |
IN | 3.1 | 3.4 | 3.2 |
(Figs
Body relatively short (AG/SVL 0.43) with well-defined ventrolateral folds; dorsal scales small, granular, interspersed with small, rounded, semi-regularly arranged, smooth tubercles; tubercles extend from occiput onto base of tail forming transverse rows; approximately 14 longitudinal rows of tubercles at midbody; approximately 46 paravertebral tubercles; 36 flat, imbricate, ventral scales much larger than dorsal scales; five large, pore-bearing, precloacal scales; no deep precloacal groove or depression; and four rows of large post-precloacal scales on midline.
Forelimbs thin, relatively long (FL/SVL 0.16); lacking tubercles, granular scales slightly larger than those on body; palmar scales rounded, slightly raised; digits well-developed, inflected at basal interphalangeal joints; digits slightly narrower distal to inflections; subdigital lamellae transversely expanded, those proximal to joint inflections wider than those distal to inflection; claws well-developed, sheathed by a dorsal and ventral scale; hind limbs thin, more robust than forelimbs, long (TBL/SVL=0.20), covered dorsally by granular scales interspersed with slightly larger, weakly keeled tubercles and anteriorly by flat, slightly larger scales; ventral scales of thigh flat, imbricate, larger than dorsals; subtibial scales large, flat, imbricate; one row of 10(R)9(L) enlarged femoral scales terminating distally before knee, not continuous with enlarged precloacal scales; proximal femoral scales much smaller than distal femorals, the latter forming an abrupt union with smaller, rounded, ventral scales of posteroventral margin of thigh; femoral pores absent; plantar scales flat; digits well-developed, inflected at basal interphalangeal joints, slightly narrower distal to inflections; subdigital lamellae transversely expanded, those proximal to joint inflections wider than those distal to inflection, 10(R,L) transversely expanded subdigital lamellae on fourth toe proximal to joint inflection that extends onto the sole; 12(R,L) narrower lamellae distal to inflection; 22 total subdigital lamellae; and claws well-developed, sheathed by a dorsal and ventral scale at base.
Tail long (TL/SVL 1.25), original, 119 mm in length, 9.0 mm in width at base, tapering to a point; dorsal caudals small, generally square; median row of subcaudals transversely expanded, significantly larger than dorsal caudals, not extending up onto lateral side of tail; transverse rows of 2–4 keeled tubercles on anterior one-half of tail, paravertebral tubercles largest; tubercle rows separated by 7–9 rows of dorsal caudals; base of tail bearing small hemipenal swellings with three large postcloacal tubercles on either side; and postcloacal scales flat, imbricate.
Coloration in life (Figs
(Fig.
(Fig.
The new species name “raglai” is given in a reference to the Raglai people, an ethnic group living in the forested mountain areas of Khanh Hoa Province of Vietnam, including the Song Giang River Valley where the new species was found. In Raglai language, the self-designating word “raglai” also means “forest”, stressing the importance of the tropical forest ecosystem for this people. To reflect this polysemy, the new species name is given as a noun in apposition and hence is invariable.
Within the Cyrtodactylus irregularis group, C. raglai sp. nov. is most closely related to C. kingsadai, C. cryptus, and an undescribed species from Ba Na with which it forms a monophyletic group. It differs from both the described species in having a far greater maximum SVL (111.7 mm vs. 90.8–94 mm collectively) and fewer precloacal pores in the single male specimen (five vs. 7–11, collectively). It differs further from its sister species C. kingsadai in having significantly fewer supralabials (10 or 11 vs. 10–14, collectively), longitudinal rows of tubercles (14 or 15 vs. 14–23, collectively), and ventral scales (36–39 vs. 39–46, collectively), and a significantly longer head (adjusted head length 3.29–3.34 vs. 3.21–3.29, collectively) (Table
Cyrtodactylus raglai sp. nov. was recorded in the forested valley of Song Giang River in the northwestern part of Khanh Hoa Province (Fig.
Cyrtodactylus raglai sp. nov. is the sixth species of Cyrtodactylus to have a cave habitat preference and the first species to do so in the irregularis group. Morphometric comparisons of C. raglai sp. nov. to other closely related members of the irregularis group could not be evaluated using the complete data set of
General morphology of the six species of cave ecomorphs in the genus Cyrtodactylus from Vietnam. A. C. raglai sp. nov. from the Song Giang River Valley, Khanh Hoa Province. Photograph by Anh The Nguyen. B. C. hontreensis from Hon Tre Island, Kien Giang Province. Photograph by L. Lee Grismer. C. C. grismeri from Tuc Dup Hill, An Giang Province. Photograph by L. Lee Grismer. D. C. badenensis from Ba Den Mountain, Tay Ninh Province. Photograph by Nikolay A. Poyarkov. E. C. nigriocularis from Ba Den Mountain, Tay Ninh Province. Photograph by Nikolay A. Poyarkov. F. C. eisenmanae from Hon Son Island, Kien Giang Province. Photograph by Ngo Van Tri.
The description of Cyrtodactylus raglai sp. nov. continues to underscore the fact that the mountainous areas of southern Vietnam harbor more species of Cyrtodactylus than any other area in the country. This recent discovery of yet another narrow-range endemic, is a clear indication that the true diversity of this area is not yet known. This makes it all the more important the urgent need for continued field work in this region, and in particular, forested areas with granitic outcroppings where more narrow-range endemics are likely to be discovered. To date, Cyrtodactylus raglai sp. nov. is known only from a narrow area within the Song Giang River Valley. In 2014, a significant part of this valley was partially flooded after the construction of the Song Giang Hydropower Station. A second hydropower station on the Song Giang River is currently under construction and is expected to be completed in 2022. Economic growth in Khanh Hoa Province requires additional electricity, and the plans for further development of hydropower stations on the Song Giang River will likely have a strong impact on the hydrological regime of the river and the surrounding forest ecosystems. Currently, this forested area has no legal protection. Therefore, an urgent need for additional herpetological surveys in the Song Giang River Valley is crucial for estimating its biodiversity and importance for nature conservation in southern Vietnam. Given the relatively small estimated range of Cyrtodactylus raglai sp. nov. and the increasing threats to the ecosystem where it was found, further research is urgently required to clarify the extent of its distribution, population trends, and conservation status. Because C. raglai sp. nov. is known only from three specimens, we tentatively suggest it should be categorized as Data Deficient (DD) according to the IUCN’s Red List categories (IUCN Standards and Petitions Committee, 2017).
We thank the Bureau of Forestry, Ministry of Agriculture and Rural Development of Vietnam and of administration of Khanh Hoa Province for permitting the fieldwork. Anh The Nguyen thanks Vu Long (Center for Biodiversity conservation and Endangered Species, CBES) and Pham Van Hieu for numerous support and assistance in during the field surveys. Nikolay A. Poyarkov expresses his gratitude to Andrey N. Kuznetsov (Joint Russian-Vietnamese Tropical Research and Technological Center) for supporting his work in Vietnam. Fieldwork, specimen collection, and molecular phylogenetic analysis for this paper were conducted with the financial support of the Russian Science Foundation (RSF Grant No. 19-14-00050 to Nikolay A. Poyarkov). The authors thank two anonymous reviewers for their useful comments on an earlier draft of the manuscript.