A taxonomic revision of the genus Raorchestes in Myanmar and Thailand with the description of two new species from Myanmar (Amphibia, Anura, Rhacophoridae)

We revise the frogs of the genus Raorchestes from Myanmar and Thailand based on data of external morphology, bioacoustics, and molecular genetics. The results of this integrative study provide evidence for the recognition of seven species, two of which we describe as new: Raorchestes mindat sp. nov. from Mindat District, Chin State, western Myanmar, and Raorchestes leiktho sp. nov. from Hpa-an District, Kayin State, southeastern Myanmar.

The other species that we recognize in Myanmar and Thailand are R. cangyuanensis, R. huanglianshan, R. longchuanensis, R. menglaensis, and R. parvulus. We have compared the external morphology of the lectotype and four paralectotypes of Ixalus parvulus Boulenger, 1893 with the species of the Raorchestes parvulus group currently recognized from South-east Asia. Although the type series of Ixalus parvulus is morphologically most similar to specimens of R. cangyuanensis from Thailand, we refrain from formally synonymizing these two taxa until genetic data for I. parvulus are available that would allow this hypothesis to be tested.

Thus, R. parvulus remains an enigmatic taxon still only known from the original type series. As now defined, R. cangyuanensis is distributed across most of Myanmar except for the Malayan Peninsula, and also in adjacent Yunnan Province, China, and adjacent northeastern Bangladesh. Raorchestes longchuanensis occurs in northwestern Thailand as well as in eastern Myanmar and western Yunnan, China.

Raorchestes menglaensis ranges from southern Yunnan, China, across Thailand, Laos, and Cambodia to northern Western Malaysia. Raorchestes huanglianshan is distributed in southern Yunnan, China, and northwestern Thailand. Often two, at some places even three species of this genus occur sympatrically (e.g., R. leiktho sp. nov., R. longchuanensis and R. parvulus near Leiktho, Kayin State, Myanmar; R. longchuanensis and R. huanglianshan at Doi Inthanon).

We provide new bioacoustic data for R. longchuanensis, R. menglaensis, and R. leiktho sp. nov., and compare these with data of R. cangyuanensis and R. rezakhani.