We collected nine specimens of Odorrana Fei, Ye & Huang, 1990 from Xishuangbanna Prefecture, Yunnan Province, China, which is close to the type locality of O. heatwolei (Stuart & Bain, 2005) in Phongsaly Province, northern Laos (approximately 60 km). These specimens agree with the diagnosis of O. heatwolei that body size is large in females and relatively small in males, tympanum large in males and relatively small in females, first finger longer than the second, and glandular dorsolateral fold and external vocal sacs present in males, moreover, these specimens have obvious dense tiny black dots scattered on the dorsum, which is consistent with the characters of O. heatwolei and different from O. tiannanensis (Yang & Li, 1980). Phylogenetically, the sequences of these specimens clustered with the sequence of the holotype of O. heatwolei and formed a distinct clade together, which is sister to O. tiannanensis. We resurrect O. heatwolei and extend the distribution of this species to China.

16S rRNA, China, Laos, new record, revalidation, taxonomy

The odorous frogs of the genus Odorrana Fei, Ye & Huang, 1990 comprise a species-rich group of ranids whose range covers the Ryukyu Archipelago, southern China, northeastern India, and Indochina, and extend southwards to Sumatra and Borneo (Frost 2023). This genus contains 62 recognized species to date, more than half of which occur in southern China (AmphibiaChina 2023; Frost 2023).

Odorrana tiannanensis (Yang & Li, 1980), a species of Odorrana, was considered to be widely distributed in southern Yunnan, China, and northern Vietnam and northern Laos (Yang and Li 1980; Yang and Rao 2008; AmphibiaChina 2023; Frost 2023), and its type locality is in Hekou County, Yunnan Province, China (Yang and Li 1980). Rana heatwolei Stuart & Bain, 2005 is a species described from Phongsaly Province, northern Laos, and was placed into synonymy of O. tiannanensis based on morphological characteristics by Ohler (2007). Poyarkov et al. (2021) regarded it as O. heatwolei (Stuart & Bain, 2005) and considered it to be a valid species but did not provide any evidence.

During our field surveys in southern Yunnan Province, China, from 2019 to 2021, we collected 11 specimens of Odorrana tiannanensis from its type locality Hekou County, and from Gejiu City and Malipo County, and nine specimens of O. cf. tiannanensis from Mengla County, which is close to Phongsaly, the type locality of O. heatwolei in northern Laos (Fig. 1). Molecularly, the sequences of these specimens from Mengla clustered with the sequence of the holotype (FMNH 258134) of O. heatwolei and the sequences which were also collected from Phongsaly but identified as O. tiannanensis from GenBank, and together, they formed a distinct clade sister to O. tiannanensis. The morphological characters of the specimens from Mengla agree with the original description (Stuart and Bain 2005) of O. heatwolei but differ from O. tiannanensis.

Figure 1. 

Map showing the type locality (black dot) of O. tiannanensis, the type locality (black triangle) of O. heatwolei, the type locality (black square) of O. macrotympana, the new collection site (black star) of O. heatwolei, and the new collection sites (black diamonds) of O. tiannanensis.

Herein, we resurrect Odorrana heatwolei and first report this species from China.

The sequence alignment is 1090 bp in length. The Maximum likelihood and Bayesian inference phylogenetic trees were essentially consistent. The sequences of the specimens from Mengla, Yunnan, China, the sequence of the holotype (FMNH 258134) of Odorrana heatwolei, and the sequences identified as O. tiannanensis from Phongsaly, Laos, clustered together, and they formed a distinct clade sister to O. tiannanensis with strong supports (Bayesian posterior probability 1, Maximum likelihood bootstrap support 98) (Fig. 2). The genetic divergence (uncorrected p-distance) between the sequences of the specimens from Mengla and the sequence of the holotype (FMNH 258134) of O. heatwolei was 0.20%, between the sequences identified as O. tiannanensis from Phongsaly and the sequence of the holotype (FMNH 258134) of O. heatwolei was 0.28%, between the sequences of the specimens from Mengla and the sequences of O. tiannanensis was 6.51%, and between the sequence of the holotype (FMNH 258134) of O. heatwolei and the sequences of O. tiannanensis was 6.47% (Table 2).

Figure 2. 

Bayesian inference tree of the genus Odorrana based on the mitochondrial 16S rRNA sequences. Numbers before slashes indicate Bayesian posterior probabilities (≥ 0.90) and numbers after slashes indicate bootstrap supports from Maximum likelihood analysis (≥ 90).

Morphologically, the specimens from Mengla differ from Odorrana tiannanensis by having obvious dense tiny black dots scattered on dorsum and lacking large black dots on dorsum (Figs 3A, C, 4) whereas having distinct or indistinct large black dots on dorsum and lacking dense tiny black dots scattered on dorsum in O. tiannanensis (Figs 3B, D, 5). However, morphological characters of the specimens from Mengla are similar to the original description and pictures of O. heatwolei in Stuart and Bain (2005).

Figure 3. 

Comparison between Odorrana heatwolei and O. tiannanensis in life. A. Adult male O. heatwolei from Mengla, Yunnan, China; B. Adult male O. tiannanensis from Hekou, Yunnan, China; C. Adult female O. heatwolei from Mengla, Yunnan, China; D. Adult female O. tiannanensis from Hekou, Yunnan, China.

Figure 4. 

Dorsal view (A), lateral view (B), and ventral view (C) of the male (KIZ20194255) and dorsal view (D), lateral view (E), and ventral view (F) of an adult female (escaped) of Odorrana heatwolei from China in life.

Figure 5. 

The type specimens of Odorrana tiannanensis in preservative. A. Dorsal; B. Ventral views of the holotype (KIZ 77I0185, male); C. Dorsal; D. Ventral views of the allotype (KIZ 77I0137, female).

Therefore, we consider the specimens from Mengla to be Odorrana heatwolei which were originally described as Rana heatwolei by Stuart and Bain (2005). We formally remove O. heatwolei from the synonymy of O. tiannanensis.

Taxonomy

 Odorrana heatwolei (Stuart & Bain, 2005)

Figs 3A, C, 4, 6, 7

Rana heatwolei Stuart & Bain, 2005

Rana tiannanensis – Ohler, 2007

Odorrana heatwolei – Poyarkov et al., 2021

Type material

Holotype : FMNH 258134, adult male.

Paratypes. FMNH 258279–83, 258598, six females; FMNH 258135–39, five males.

Type locality

Phou Dendin National Biodiversity Conservation Area, Phongsaly District, Phongsaly Province, Laos (22°05'38"N, 102°12'50"E; alt. 600 m).

Figure 6. 

Dorsal view (A) and ventral view (B) of the specimens of Odorrana heatwolei from China in preservative.

Etymology

The specific epithet is a patronym for Dr. Harold F. Heatwole. We propose “Dense-spotted Odorous Frog” for the English name and “麻点臭蛙” (má diǎn chòu wā) for the Chinese name.

Figure 7. 

Close-up views of the head (A), vola (B), and planta (C) of the male (KIZ2019541) and close-up views of the head (D), vola (E), and planta (F) of the female (KIZ2019542) of Odorrana heatwolei from China in preservative.

Updated diagnosis

Habitus robust; body sizes of females approximately two to three times that of males, SVL 37.1–57.3 mm in adult males, 97.3–106.7 mm in adult females; head length slightly greater than head width; dorsal skin shagreened, skin on flanks granular; supratympanic fold present; dorsolateral folds distinct in males and indistinct in females; tympanum large in males (TD/ED 0.58–0.73) and relatively small in females (TD/ED 0.45–0.58); vomerine teeth distinct; relative lengths of fingers III > IV > I > II; inner metacarpal tubercle and outer metacarpal tubercle present, outer metatarsal tubercle absent; all finger and toe tips slightly expanded; toes with entire webbing to disks; uniform light brown or dark brown on whole body, dense tiny black dots scattered on dorsum; paired external vocal sacs and nuptial pad on the base of finger I present in adult males.

Specimens examined

KIZ20194255, adult male, and KIZ20194256–KIZ20194258, three adult females, collected on 24 April 2019 from Mandan village, Mengla Town, Mengla County, Xishuangbanna Prefecture, Yunnan Province, China (21°28'59"N, 101°40'29"E, 780 m elevation) by Shuo Liu; KIZ20194279, adult female, collected on 27 April 2019 from Mengyuan village, Guanlei Town, Mengla County, Xishuangbanna Prefecture, Yunnan Province, China (21°38'35"N, 101°26'54"E, 950 m elevation) by Shuo Liu; KIZ20194301–KIZ20194302, two adult males, collected on 30 April 2019 from Bubeng village, Mengla Town, Mengla County, Xishuangbanna Prefecture, Yunnan Province, China (21°36'21"N, 101°33'27"E, 800 m elevation) by Shuo Liu; KIZ2019541, adult male, and KIZ2019542, adult female, collected on 4 May 2019 from Xinshan village, Yaoqu Township, Mengla County, Xishuangbanna Prefecture, Yunnan Province, China (21°54'59"N, 101°32'16"E, 840 m elevation) by Shuo Liu.

Description of the specimens from China

Morphometric and meristic data are presented in Table 3. SVL 46.8–51.7 mm in males, 97.4–106.7 mm in females; head width slightly shorter than length (HW/HL 0.87–0.91 in males, 0.93–0.98 in females); snout obtuse, pointed in dorsal view and rounded in profile, obviously projecting beyond lower jaw; nostril closer to snout than to eye; canthus rostralis distinct; loreal region concave; internarial distance greater than interorbital distance; snout length greater than eye diameter; pineal body distinct; supratympanic fold horizontal and straight; tympanum large in males (TD/ED 0.66–0.73) and relatively small in females (TD/ED 0.48–0.58), round and transparent; vomerine teeth developed into mass on two oblique ridges between the two choanae; tongue cordiform, posterior notch enlarged and formed as U-shaped; vocal sac openings on floor of mouth in each corner and an external vocal sac behind each angle of mouth in males.

Table 3.

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Morphological measurements (mm) of the specimens of Odorrana heatwolei from China.

	KIZ2019541 Male	KIZ20194301 Male	KIZ20194302 Male	KIZ20194255 Male	KIZ20194256 Female	KIZ20194257 Female	KIZ20194258 Female	KIZ20194279 Female	KIZ2019542 Female
SVL	51.7	48.3	48.8	46.8	97.4	102.7	103.4	106.7	104.2
HL	21.8	20.3	19.6	19.7	37.5	37.7	37.4	39.2	39.0
HW	19.1	17.7	17.9	17.2	34.9	36.1	35.7	36.9	38.4
SL	8.9	8.8	8.3	8.5	16.4	15.7	16.3	16.4	16.6
IND	5.4	5.8	5.3	5.5	10.3	10.0	9.8	10.4	11.0
IOD	4.2	4.1	4.0	4.6	8.7	9.4	8.1	9.6	9.5
ED	7.2	7.6	7.1	7.0	10.5	11.0	10.9	12.2	11.1
UEW	5.2	5.1	4.8	4.8	7.5	7.7	7.6	7.7	8.4
TD	5.2	5.3	4.7	5.1	6.1	5.9	6.0	5.8	5.7
TED	1.7	1.5	1.5	1.6	4.5	4.4	4.7	5.0	4.8
FHL	28.2	25.7	26.4	26.3	49.1	51.2	50.3	53.0	55.1
HAL	16.0	15.1	15.3	15.6	28.6	30.1	29.6	31.4	31.9
TL	34.3	31.5	32.9	31.2	65.6	66.5	65.9	70.4	71.8
TFL	44.1	40.3	42.0	40.6	83.2	86.0	82.6	90.6	94.1
FTL	29.5	27.3	28.4	26.9	55.7	59.0	56.5	60.7	65.0
FDW3	1.9	1.9	1.8	1.8	3.7	3.5	2.6	3.6	4.0

Forelimbs robust; relative lengths of fingers III > IV > I > II; all finger tips slightly expanded; lateral fringes and webbing on fingers absent; subarticular tubercle round and prominent; one oval thenar tubercle prominent on the ventral of finger I; inner metacarpal tubercle and outer metacarpal tubercle distinct; supernumerary tubercles at the base of fingers II–IV; grayish-yellow nuptial pad on finger I in adult males.

Hind limbs long, tibia longer than thigh; toes long, relative lengths IV > V > III > II > I; all toe tips slightly expanded; toes with entire webbing to disks; subarticular tuber­cles prominent and longitudinally ovoid; inner metatarsal tubercle prominent and oval; outer metatarsal and supernumerary tubercles absent.

Dorsal skin shagreened with some very indistinct tubercles, skin on flanks granular, ventral skin smooth, and dorsolateral folds distinct in males. Skin slightly smoother and dorsolateral folds more indistinct in females.

Coloration in life

Dorsum brown scattered with dense tiny brownish black dots; upper lip yellowish white with indistinct dark spots; lower lip creamy white with distinct dark spots; lateral side of head and body brown with many irregular dark brown spots; dorsal surfaces of limbs brown with some indistinct dark brown bands; ventral surface of head and forelimbs, chest, and belly creamy white; ventral surface of hindlimbs light yellow; buttocks slightly pink; tympanum dark brown; and iris yellow in males. Coloration in females very similar to but usually slightly lighter than that in males.

Coloration in preservative

Dorsum color turned darker to grayish black, the dense tiny black dots on dorsum still visible, dorsal color of limbs turned darker to brownish black, the bands on limbs became indistinct. Ventral color of head and forelimbs, chest, and belly faded to pale white, ventral color of hindlimbs turned to flesh color. Iris became black, pupil became white.

Natural history

The specimens from China were all found on the banks of rivers at night. No eggs or tadpoles were found from April to May. There were many stones and forests with good vegetation on the banks of the river (Fig. 8). An Amolops species of Amolops cf. vitreus (Bain, Stuart & Orlov, 2006) is distributed sympatric with this species.

Figure 8. 

The habitat at the collection site of the specimens of Odorrana heatwolei in Mengla, Yunnan, China.

Distribution

Currently known in Phongsaly Province, Laos, and Xishuangbanna Prefecture, Yunnan Province, China (Fig. 1).

Ohler (2007) took Odorrana heatwolei as a synonym of O. tiannanensis based on only morphological characteristics. These two species are indeed very similar in morphological measurements, but their body colorations are significantly different. In addition, these two species form two separate lineages molecularly and the genetic distance between them is large.

The straight distance between the type locality of Odorrana heatwolei and the type locality of O. tiannanensis is approximately 200 km, and they are separated by the Red River (Song Hong River in Vietnam). The straight distance between the collection site of the specimens of O. heatwolei from Xishuangbanna, Yunnan, China, and the type locality of O. heatwolei is approximately 60 km, and there is no obvious geographical obstacle between them. These specimens from Xishuangbanna are the first record of O. heatwolei from China.

Odorrana tiannanensis was considered previously to be widely distributed in southern Yunnan, China, and northern Vietnam and northern Laos (Frost 2023). We found that this species is likely to be distributed only in the east of the Red River including southeastern Yunnan, China, and northeastern Vietnam, and O. heatwolei is likely to be distributed only in the west of the Red River including south-central and southwestern Yunnan, China, and northern Laos. More samples are needed to verify the geographical isolation between the two species.

It was found previously that Odorrana macrotympana and O. tiannanensis are closely related (Liu et al. 2022), however, the distributions of these two species are far apart, one in westernmost Yunnan and northern Myanmar, and the other one in southeastern Yunnan (Fig. 1), and no other species was found that can connect these two species in the large area between their distributions, which seems unlikely. Odorrana heatwolei just filled this gap. However, the distribution of O. heatwolei is close to that of O. tiannanensis and far apart from that of O. macrotympana. Therefore, we speculate that there may be species that can connect O. heatwolei and O. macrotympana in the area between their distributions. More investigations in these areas are needed to verify this speculation.

Thanks to Dr. Bryan L. Stuart very much for providing the sequence of the holotype of Odorrana heatwolei. Thanks to Hong Hui for providing photos. We thank our workmates for their help and advice. Thanks also to the editors and reviewers for their work on the manuscript. This work was supported by Science-Technology Basic Condition Platform from the Ministry of Science and Technology of the People’s Republic of China (Grant No. 2005DKA21402); the project of the second comprehensive scientific investigation of Xishuangbanna National Nature Reserve; and the project of Ministry of Ecology and Environment of China: investigation and assessment of amphibians and reptiles in Jinghong City, Menghai County, and Mengla County.