Saturday, June 25, 2016

[Herpetology • 2016] Raorchestes silentvalley & R. lechiya • Two New Species of Raorchestes (Anura: Rhacophoridae) from the Silent Valley National Park in the Nilgiri Hills of the Western Ghats, India

Raorchestes silentvalley   &   R. lechiya 

Zachariah, Cyriac, Chandramohan, Ansil, Mathew, Raju & Abraham. 2016
  SALAMANDRA. 52(2); 63–76. ||

Two new species of rhacophorid bush frogs of the genus Raorchestes are described from the tropical montane wet forests in the Silent Valley National Park in the Nilgiri Hills, a high horst in the Western Ghats, India. Both species can be differentiated from their congeners by morphological and bioacoustic characters as well as differences in the mitochondrial 16S gene. Advertisement calls of the two new species are provided and tentative insights into the phylogenetic position discussed. Despite recent revisions of this genus from the Western Ghats, and the fact that the Silent Valley National Park is one of the most important and well-surveyed protected areas, the results of this study highlight the overlooked diversity in this area. 

Key words. Amphibia, bush frog, species description, South Asia, protected area, montane habitat, taxonomy.

Figure 3. Raorchestes silentvalley sp. n. (in life): A) vocalizing male; B) ventral coloration of a live individual (Paratype); C) spotted pattern on palpebral membrane; D) dorsal colour variation in other male individuals.
Figure 7. Raorchestes lechiya sp. n. (in life): A) male holotype (TNHM (H) 12.6.18/55); B) vocalizing male (not collected); C) male in amplexus (TNHM (H) 12.6.18/55) with a female (not collected).  

Raorchestes silentvalley sp. n. 
ZooBank LSID:
Suggested common name: Silent Valley bush frog 

Etymology: The specific epithet silentvalley refers to the Silent Valley National Park in Kerala, India, where the species was observed and collected. 

Distribution and Natural History: Thus far, Raorchestes silentvalley sp. n. has been recorded only from the montane wet forests (Figs 6A, B) of the southwestern slopes of the Nilgiri Hills (Fig. 1). The species was observed at Sispara and the higher areas of Thudukki, both of which are situated in the Silent Valley National Park in Kerala at altitudes ranging between 1,850 and 2,200 m a.s.l. Vocalising individuals were perched 1–2.5 m above the forest floor on the branch-es and foliage of understorey shrubs (dominated by Strobi­lanthes lawsonii and occasionally by S. lanata) (Fig. 6C) and small tree saplings, in May. Several vocalising males were observed with blood-sucking leeches attached to them.

Raorchestes lechiya sp. n. 
ZooBank LSID:
Suggested common name: Lechiyappan’s bush frog

Etymology: The species name is a tribute to the late Mr. Lechiyappan of the Mudugar tribe, a forest tracker at Silent Valley National Park. He was instrumental in the early conservation undertakings of the Silent Valley Movement, which eventually led to the declaration of the area as a National Park.

Distribution and Natural History: Raorchestes lechiya sp. n. was found only in the upper reaches of the southwestern slopes of the Nilgiri Hills (Fig. 1) at altitudes ranging from 1,800–2,200 m a.s.l. We found the species inhabiting the leaf litter and understorey vegetation in montane wet forests (Figs 6A, B). We also observed individuals vocalising from branches of shrubs at an average height of 1 m from the ground, as well as an amplectant pair (Fig. 7C). 

Anil Zachariah, Vivek Philip Cyriac , Bathrachalam Chandramohan, Basheer Rahmath Ansil, Jobin K. Mathew, David V. Raju and Robin Kurian Abraham. 2016. Two New Species of Raorchestes (Anura: Rhacophoridae) from the Silent Valley National Park in the Nilgiri Hills of the Western Ghats, India. SALAMANDRA. 52(2);  63–76.