Description
This species is an “Asian Tree Frog” belonging to the genus Rhacophorus. The following description is based on the male holotype and single female paratype of the species, collected together from Dulongjiang Village in Yunnan, China on 15 February 2022. The adults of the species are rather small, with a snout-vent length typically measuring around 33 mm. It is worth noting that the female paratype was recorded to be minimally larger than the male, measuring 35.3 mm and 31.7 mm respectively. Rhacophorus dulongensis heads are longer than wide, with head lengths of around 10 mm and head widths of just under 9 mm. They have pointed snouts that protrude from their lower jaw. The space from nostril to eye is longer than the internarial space, at 3.5 mm. The species has a distinct canthus rostralis and an oblique loreal region. The pupils are horizontal and the eye diameter is equal to the nostril-eye distance at 2.7 mm. The size of the upper eyelids is smaller than the eye diameter and the rounded tympanum is shorter than half of the eye diameter. The interorbital space is slightly larger than the diameter of the eyes. Rhacophorus dulongensis do not have a pineal ocellus but do have a distinct supratympanic fold. Rhacophorus dulongensis is also characterized by a granular and rough belly, while the dorsum and ventral body and limbs are smooth. Their forelimbs are slim and somewhat short, with the lower arm to hand length being shorter than half of their body length. Their forelimbs have four fingers of varying lengths, their third digit being the longest, followed by the fourth, then the second, and then the first being the shortest. Each fingertip expands into discs, which aid in tree climbing, and each finger has supernumerary tubercles at its base. Their subarticular tubercles and inner metacarpal tubercles are distinct. The species does not have nuptial pads or linear masculinae. The hind limbs are slim and long, with the hind limb length reaching 50 mm in length and the tibiotarsal articulation reaching the eye when adpressed along the body. The tibia length is recorded to be shorter than half of the snout-vent length and shorter than the thigh as well. The hind limbs each have 5 digits with the fourth being the longest, then the fifth, third, second, and first. They also have discs at the tips as well as visible webbing (Lee et al. 2024).

The species is generally identifiable by its small size, a head that is distinctly longer than wide, dark goldenrod-colored irises, a pointed but non-bulbous snout, a tympanum larger than the third finger disk, and a tibiotarsal articulation that reaches the eye. However, it does have phylogenetically close congeners that share morphological traits. Two examples are R. tuberculatus and R. orlovi. Dorsal coloration can be used to easily distinguish R. dulongensis from R. tuberculatus, as in life the former is green while the latter is brown. Moreover, R. tuberculatus has a distinct calcar at tibiotarsal articulation and dark stripes on the hind limb, which is absent in R. dulongensis. When it comes to R. orlovi, R. dulongensis has a smaller head length and different dorsal coloration; live R. orlovi are reddish brown with transverse stripes on the hind limbs and spotting on the flanks. Rhacophorus dulongensis also has large black warts on the ventral thigh, which is not present in the other species (Lee et al. 2024).

Dorsally, the R. dulongensis holotype was uniformly green, while the legs were brown with irregular green splotches. Ventrally, the coloration was irregular. There was a black dusting on the margins of the throat, while the color on the belly was yellowish. Near the vent, on the thigh, there were large black warts. Toe webbing was red (Lee et al. 2024).

In preservative, the holotype’s coloration shifts but overall keeps the patterning of spots and markings throughout the body as live specimens. The dorsal coloration darkens while the ventral surface lightens. The ventral throat dusting lightens to a brown color and spreads from just the margins. Additionally, the large black warts near the vent become more notable (Lee et al. 2024).

Dusting patterns on the belly, chest, throat, and undersides of the limbs differ between the two individuals used to describe the species. The female paratype has more notable brown dusting on the venter than male conspecifics and was slightly larger in snout-vent length (Lee et al. 2024).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: China

View distribution map in BerkeleyMapper.

The two specimens used to describe the species were found in bamboo internodes near streams in the Gaoligong Mountains, close to Dulongjiang Village in Yunnan, China. While it's suspected that the species may be distributed across the Gaoligong Mountains in China and Myanmar, this had not been confirmed at the time of the species description. They likely inhabit areas of continuous, montane forest within evergreen broadleaf woodlands (Lee et al. 2024).

Life History, Abundance, Activity, and Special Behaviors
Given that both observed specimens were found inside bamboo, it is suspected that the species nests within bamboo internodes. However, at the time of the species description, no tadpoles or vocalizations have been recorded yet (Lee et al. 2024).

Larva
At the time of the species description, larvae had not yet been observed. However, based on genus-wide traits it can be assumed that R. dulongensis undergoes direct development (Lee et al. 2024).

Trends and Threats
The species is thought to breed in bamboo in an area that is experiencing anthropogenic pressures and the effects of climate change. However at the time of the species description, the species was considered "Data Deficient" (Lee et al. 2024).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Climate change, increased UVB or increased sensitivity to it, etc.

Comments
Bayesian and Maximum Likelihood analyses conducted on the 16S rRNA gene as well as morphological analyses were conducted. The findings supported the classification of R. dulongensis as a distinct species within the Rhacophorus genus that is most closely related to R. tuberculatus (Lee et al. 2024).

References
Lee, P.-S., Liu, B., Ouyang, M., Ai, R.-D., Liu, X.-L., He, Y.-H., Huang, P.-Q., Li, Y.-C., Naveen, R. S., Yuan, Z.-Y., and Chen, J.-M. (2024). Hidden in the bamboo: A new parachuting frog (Rhacophoridae, Rhacophorus) from the borderlands of western China, with comments on the taxonomy of R. rhodopus. Zoosystematics and Evolution, 100(3), 851–862. [link]

Species Account Citation: AmphibiaWeb 2024 Rhacophorus dulongensis: Dulongjiang tree frog (English) <https://amphibiaweb.org/species/9864> University of California, Berkeley, CA, USA. Accessed May 16, 2025.

Citation: AmphibiaWeb. 2025. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 16 May 2025.

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