[Herpetology • 2025] Raorchestes magnus, R. monolithus, R. nasuta, R. orientalis ... • Revision of Bush Frogs, Raorchestes and Philautus (Anura: Rhacophoridae) from the northeast Indian Biodiversity Hotspot with Description of Thirteen New Species

Raorchestes nasuta, R. monolithus, R. orientalis,
R. khonoma, R. arunachalensis, R. magnus, ...

 Boruah, Deepak & Das, 2025 

DOI: doi.org/10.3897/vz.75.e148133 

 facebook.com: Bitupan Boruah 

Abstract

Bush frogs currently in the genera Raorchestes and Philautus are poorly documented from northeast India when compared to the Western Ghats of southwestern India. They are morphologically cryptic, but variable in their acoustic repertoire and genetic divergence. We present a long-overdue revision of the bush frogs of northeast India by sampling 81 localities in eight Indian States (including nine type localities of known species) and by comparing historical (especially, type) material. Using an integrative approach that combines levels of divergence in mitochondrial DNA, a nuclear-encoded gene and comparing morphological and bioacoustic data, we demonstrate the existence of 13 new species, which are formally described here. In addition, based on the evidence from molecular and morphological data we synonymise four previously described species from this region. We resolve the taxonomic identities of three other frog species found in northeast India. After extensive survey across northeast India, we did not find a single specimen of the genus Philautus. The only species in this genus with ambiguous generic identity is P. dubius which requires further taxonomic investigation.

Keywords: Bioacoustics, cryptic species, Indo-Burma, Indochina, morphology, phylogeny, redescription, taxonomy 

Raorchestes orientalis sp. nov.

Raorchestes mawsynramensis sp. nov.

Raorchestes boulengeri sp. nov.

Raorchestes barakensis sp. nov.

Raorchestes narpuhensis sp. nov.

Raorchestes lawngtlaiensis sp. nov.

Raorchestes nasuta sp. nov.

Raorchestes dibangensis sp. nov.

Raorchestes monolithus sp. nov.

Raorchestes khonoma sp. nov.

Raorchestes eaglenestensis sp. nov.

Raorchestes arunachalensis sp. nov.

Raorchestes magnus sp. nov.

Raorchestes cinerascens  comb. nov., 

Raorchestes tytthus  comb. nov.,

 Liurana kempii  comb. nov., 

Nasutixalus microdiscus comb. nov.

 Bitupan Boruah, V. Deepak and Abhijit Das. 2025. Revision of Bush Frogs, Raorchestes and Philautus (Amphibia: Anura: Rhacophoridae) from the northeast Indian Biodiversity Hotspot with Description of Thirteen New Species. Vertebrate Zoology. 75: 517-625. DOI: doi.org/10.3897/vz.75.e148133 

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[Herpetology • 2020] Raorchestes kollimalai • A New Cryptic Species of Bush Frog (Anura: Rhacophoridae: Raorchestes) from the Southern Eastern Ghats, India

 Raorchestes kollimalai 

Gowande, Ganesh & Mirza, 2020

DOI: 10.47605/tapro.v9i2.229

 facebook.com: Zeeshan A. Mirza 

Abstract

A new cryptic lineage of bush frogs of the genus Raorchestes from the understudied Eastern Ghats of India is described. Molecular phylogenetic reconstructions using mitochondrial 16S rRNA gene sequences suggest that the new species belongs to the Raorchestes charius clade, is sister to the allopatric R. charius of the Western Ghats and support the species-level distinctiveness of the lineage. The new species morphologically resembles R. charius from which it can be distinguished using the following characters: narrower head (HW/SVL 0.31 vs 0.34–0.36), wider inter upper eyelid (IUE/SVL 0.14–0.16 vs 0.11–0.13), greater maximum upper eyelid width (UEW/SVL 0.10–0.12 vs 0.06–0.09) and shorter thigh (TL/SVL 0.32–0.43 vs 0.44–0.51). Acoustic observations from the breeding males further corroborate the distinct specific status of the new species. The discovery of this new species of bush frog from an understudied landscape suggests that additional extensive surveys in the Eastern Ghats would yield several more amphibian lineages yet unknown to science.

Key words: arboreal frog, cryptic species, Kollimalai Massif, Philautus, Rhachophoridae, systematics.

 Raorchestes kollimalai sp. nov.

Diagnosis. Raorchestes kollimalai sp. nov. is allocated to the genus Raorchestes based on the following combination of diagnostic characters: relatively small adult body size (SVL 15–45 mm), absence of vomerine teeth, presence of vocal sacs, which appear transparent/translucent while calling, and nocturnal habits. Dorsum light brown with dark brown spots. Canthus rostralis dark brown, a dark brown streak from posterior of the eye through the tympanic region terminating at the shoulder. Legs banded with dark brown. Pupil black with gold specks around it. A medium-sized bush frog (SVL 25.8–29.7 mm, n=3), characterized by wider than long head (HW/SVL 0.31, HL/SVL 0.26-0.30), short or subequal snout in comparison to the eye (SL/SVL 0.12–0.14 vs EL/SVL 0.14–0.15) and by relatively shorter hind limbs (ShL/SVL<0.50).

Etymology. The specific epithet refers to the type locality, Kollimalai, as a noun in apposition and hence invariable. Suggested common name: Kollimalai bush frog.

 

Gaurang G. Gowande, S.R. Ganesh and Zeeshan A. Mirza. 2020. A New Cryptic Species of Bush Frog (Amphibia: Anura: Raorchestes) from the Southern Eastern Ghats, India. TAPROBANICA: The Journal of Asian Biodiversity. 9(2); 164–173.DOI: 10.47605/tapro.v9i2.229

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#herpetology #amphibians #Indianamphibians #frogs #biodiversity #easternghats #frogsofindia #scf #singinawa #sanctuaryasia #sanctuarynaturefounda #WCS #wildlife 

[Herpetology • 2021] An Integrative Approach to Infer Systematic Relationships and Define Species Groups in the Shrub Frog Genus Raorchestes (Anura, Rhacophoridae), with Description of Five New Species from the Western Ghats, India

Raorchestes keirasabinae

Garg​, Suyesh​, Das, Bee & Biju,. 2021

DOI: 10.7717/peerj.10791

Abstract 

The genus Raorchestes is a large radiation of Old World tree frogs for which the Western Ghats in Peninsular India is the major center for origin and diversification. Extensive studies on this group during the past two decades have resolved long-standing taxonomic confusions and uncovered several new species, resulting in a four-fold increase in the number of known Raorchestes frogs from this region. Our ongoing research has revealed another five new species in the genus, formally described as Raorchestes drutaahu sp. nov., Raorchestes kakkayamensis sp. nov., Raorchestes keirasabinae sp. nov., Raorchestes sanjappai sp. nov., and Raorchestes vellikkannan sp. nov., all from the State of Kerala in southern Western Ghats. Based on new collections, we also provide insights on the taxonomic identity of three previously known taxa. Furthermore, since attempts for an up-to-date comprehensive study of this taxonomically challenging genus using multiple integrative taxonomic approaches have been lacking, here we review the systematic affinities of all known Raorchestes species and define 16 species groups based on evidence from multi-gene (2,327 bp) phylogenetic analyses, several morphological characters (including eye colouration and pattern), and acoustic parameters (temporal and spectral properties, as well as calling height). The results of our study present novel insights to facilitate a better working taxonomy for this rather speciose and morphologically conserved radiation of shrub frogs. This will further enable proper field identification, provide momentum for multi-disciplinary studies, as well as assist conservation of one of the most colourful and acoustically diverse frog groups of the Western Ghats biodiversity hotspot.

Raorchestes drutaahu sp. nov.

Fast-calling Shrub Frog

Etymology. The species name is derived from Sanskrit ‘druta’ (meaning fast) and ‘ahu’ (meaning call), referring to the fast-pulsatile calls of the new species. The species epithet drutaahu is treated as an invariable noun in apposition to the generic name.

Distribution and natural history. Raorchestes drutaahu sp. nov. is endemic to the Western Ghats and currently known only from elevations ranging between 1,000 to 1,450 m asl at two localities: Kadalar in Idukki district (south of Palghat gap) and Siruvani in Palakkad district (north of Palghat gap). The species has been observed in forest areas, either on grassland-shola fringes or fragmented forest patches near plantations. Individuals were located on leaves of short shrubs at heights of 0.5–1.5 m.

Raorchestes kakkayamensis sp. nov.

Kakkayam Shrub Frog

Etymology. The species is named after the place Kakkayam, where the type series was collected.

Distribution and natural history. Raorchestes kakkayamensis sp. nov. is endemic to the Western Ghats and currently known only from its type locality (Kakkayam) in Kozhikode district, north of Palghat gap in Kerala State. The species was observed inside a primary forest patch and adjoining secondary forest areas at an elevation of 750 m asl. Individuals were located on the ground leaf litter or found perching on vegetation 1–3 m high.

Raorchestes keirasabinae sp. nov.

Keira’s Shrub Frog

Etymology. The species is named after a young nature lover Keira Sabin, in appreciation of the long-time support and commitment of the Andrew Sabin Family Foundation towards amphibian research and conservation around the world. The species epithet keirasabinae is treated as a noun in the genitive case.

Distribution and natural history. Raorchestes keirasabinae sp. nov. is endemic to the Western Ghats and currently known from elevations of 100–1,000 m asl south of Palghat gap. It has been observed at Agasthyamalai Biosphere Reserve (Chathankod-Makki, Ponmudi, Peppara Wildlife Sanctuary, and Shendurney Wildlife Sanctuary) in Thiruvananthapuram and Kollam districts, and Periyar Tiger Reserve in Idukki district of Kerala State. Since the species inhabits the highest canopy layers and cannot be located easily, it could have a wider geographical range in the Western Ghats regions south of Palghat gap, both in Kerala and the adjoining State of Tamil Nadu. The vocalisations of this species have not been recorded and analysed.

Figure 16: Raorchestes chromasynchysi species group. (A) Phylogenetic relationships and major morphological characters for members of the group: (1) adult size range (male SVL 20–35 mm, female SVL 27–37 mm); (2) dorsum with a horny ridge extending from the snout tip to the vent; (3) presence of lingual papillae; (4) foot webbing moderate to large, up to or well beyond the second subarticular tubercle on either side of toe IV. (B and C) Male calls in members of the group: Calling individual, followed by a call oscillogram (above) and spectrogram (below) for R. chromasynchysi and R. silentvalley (1 s section showing a single call for each species). (D and E) Adult male, followed by a call oscillogram (above) and spectrogram (below) for R. ravii and R. sanjappai sp. nov. (0.1 s section showing a single call for each species). (F) Adult male of R. vellikkannan sp. nov. (call not studied). (G–K) Eye colour and pattern in five members of the group. (L) Geographical distribution of members of the group; species range colours on the map correspond to the square colours indicated alongside each species label in (B)–(F).

Raorchestes sanjappai sp. nov.

Sanjappa’s Shrub Frog

Etymology. The species is named after Dr. M. Sanjappa, a renowned Indian Botanist and former Director of the Botanical Survey of India. The species name is in appreciation of his taxonomic contributions as well as generous support to SDB during the initial phases of his research career. The species epithet sanjappai is treated as a noun in the genitive case.

Distribution and natural history. Raorchestes sanjappai sp. nov. is endemic to the Western Ghats and currently known only from an altitude of about 750 m asl at its type locality (Periya) that lies north of Palghat gap in the Wayanad district of Kerala State. The species was observed inside secondary forests and individuals were located on vegetation up to 3 m high during the breeding season.

Raorchestes vellikkannan sp. nov.

Silver-eyed Shrub Frog

Etymology. The species name is derived from Malayalam (the language of Kerala State where the type series were collected) ‘velli’ (meaning silver) and ‘kannu’ (meaning eye) referring to the silver colour of the iris in this species. The species epithet vellikkannan is treated as an invariable noun in apposition to the generic name.

Distribution and natural history. Raorchestes vellikkannan sp. nov. is endemic to the Western Ghats and currently known only from its type locality (Singappara, Siruvani) and surrounding regions of the Silent Valley National Park in Palakkad district of Kerala State, north of Palghat gap. This species was observed inside primary forests and individuals were found on vegetation up to 4 m high during the breeding season. The vocalisations of this species have not been recorded and analysed.

Figure 23: Ungrouped species. (A) Phylogenetic position of two ungrouped species, Raorchestes echinatus and R. indigo.
  (B–E) R. echinatus: (B) Dorsolateral view.(C) Lateral view. (D) Posterior view of thighs. (E) Eye colour and pattern.
(F–I) R. indigo: (F) Dorsolateral view. (G) Lateral view. (H) Posterior view of thighs. (I) Eye colour and pattern.
 (J) Geographical distribution of R. echinatus and R. indigo.

Sonali Garg​, Robin Suyesh​, Sandeep Das, Mark A. Bee and S. D. Biju​. 2021. An Integrative Approach to Infer Systematic Relationships and Define Species Groups in the Shrub Frog Genus Raorchestes, with Description of Five New Species from the Western Ghats, India. PeerJ. 9:e10791. DOI: 10.7717/peerj.10791

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  twitter.com/UMNFrogLab/status/1367069506854649858

[Herpetology • 2021] Raorchestes dulongensis • A New Species of Bush Frog (Anura: Rhacophoridae: Raorchestes) from northwestern Yunnan, China

 Raorchestes dulongensis 

Wu, Liu, Gao, Wang, Li, Zhou, Yuan & Che, 2021

 

DOI:  10.11646/zootaxa.4941.2.5

  twitter.com/AmphSpecWorld 

 

Abstract

Approximately half of the species in speciose genus Raorchestes were described during the past 10 years, yet only 11 species are known from Southeast Asia and southern China (SEA-SC), adjacent Himalayas, and northeastern India. Field work in northwestern Yunnan province, China resulted in the discovery of one new species in the genus based on morphological and molecular analyses. The new species is diagnosed by small size with 15.0–19.0 mm SVL in adult males (n=3); tongue pyriform, notched posteriorly; rudimentary webbing between toes; fingers and toes with narrow lateral dermal fringes; tibiotarsal articulation reaching anterior of the eye when hindlimb is stretched along the side of the body; relative finger lengths: I < II < IV < III, relative toe lengths: I < II < V < III < IV; inner metatarsal tubercle oval, outer metatarsal tubercle absent; finger discs and toe discs greyish or orange; flank near the crotch with a distinct black region between two creamy white patches, and the thigh having a similar black patch near the groin, proximal to another creamy white patch; a distinct “) (”-shaped dark marking on the back; male with external single subgular vocal sac; nuptial pad absent. A phylogenetic tree was reconstructed based on the mitochondrial genes for 16S rRNA and ND1. The results indicated that these individuals form a monophyletic group, and show high genetic divergence to their closest relatives within the genus (uncorrected p-distances > 3.2%) by distance of 16S comparable to the divergence between recognized Raorchestes species. This study further enriches the diversity of rhacophorids, especially in northwestern Yunnan.

Keywords: Amphibia, Rhacophoridae, Raorchestes, northwestern Yunnan, new species, Raorchestes dulongensis sp. nov.

 Raorchestes dulongensis sp. nov.

Yun-He Wu, Xiao-Long Liu, Wei Gao, Yu-Fan Wang, Ying-Chun Li, Wei-Wei Zhou, Zhi-Yong Yuan and Jing Che. 2021. Description of A New Species of Bush Frog (Anura: Rhacophoridae: Raorchestes) from northwestern Yunnan, China. Zootaxa. 4941(2); 239–258. DOI:  10.11646/zootaxa.4941.2.5

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[Herpetology • 2020] Raorchestes rezakhani • A New Species of Cryptic Bush Frog (Anura, Rhacophoridae, Raorchestes) from northeastern Bangladesh

Raorchestes rezakhani 

Al-Razi, Maria & Muzaffar, 2020

  DOI: 10.3897/zookeys.927.48733 

Abstract

Raorchestes is a speciose genus of bush frogs with high diversity occurring in the Western Ghats of India. Relatively fewer species have been recorded across India, through Bangladesh, southern China, into Vietnam and Peninsular Malaysia. Many bush frogs are morphologically cryptic and therefore remain undescribed. Here, a new species, Raorchestes rezakhani sp. nov., is described from northeastern Bangladesh based on morphological characters, genetics, and bioacoustics. The 16S rRNA gene distinguished this species from 48 known species of this genus. Bayesian Inference and Maximum Likelihood analyses indicated that the new species was most similar to R. tuberohumerus, a species found in the Western Ghats, and to R. gryllus, a species found in Vietnam. Bioacoustics indicated that their calls were similar in pattern to most Raorchestes species, although number of pulses, duration of pulses, pulse intervals and amplitude differentiated it from a few other species. It is suggested that northeastern India, Bangladesh, northern Myanmar, and southern China represent important, relatively unexplored areas that could yield additional species of Raorchestes. Since many remaining habitat patches in Bangladesh are under severe threat from deforestation, efforts should be made to protect these last patches from further degradation.

Keywords: Amphibian, bush frog, DNA, herpetofauna, Raorchestes rezakhani sp. nov.

Figure 4. Color variation in Raorchestes rezakhani sp. nov. A holotype, showing single transparent vocal sac during advertisement call (B holotype with brown dorsum and “)-(“ mark; C dorsolateral view of paratype (JnUZool- A0519) D ventral view of paratype (JnUZool- A0519), showing small dark brown spots.

Raorchestes rezakhani sp. nov.

 Suggested English name: Reza Khan’s bush frog

Etymology: We take great pleasure in naming the new species as a patronym for one of the pioneers in the field of wildlife research in Bangladesh, Dr. Mohammad Ali Reza Khan.

Diagnosis: A species of Raorchestes having the following unique combination of characters: (1) relatively small size (adult males = 18.85–20.90 mm SVL); (2) head wider than long (HW/HL 1.55; range 1.53–1.56, N = 4); (3) dark brown, granular dorsum bearing small, horny spicules; (4) vomerine teeth absent; (5) single transparent vocal sac while calling; (6) snout projecting, sub-elliptical in ventral aspect, and subequal to or smaller than horizontal diameter of eye; (7) tympanum indistinct; (8) supratympanic fold weakly distinct; (9) finger and toe discs well developed and rounded; (FD IV 0.50–0.60, TD IV 0.56–0.65 mm); (10) both inner and outer metacarpal and metatarsal tubercles absent; (11) nostril is closer to tip of snout than to eye (NS 0.63–0.90, EN 1.10–1.25 mm); (12) Tongue without papilla (13) venter pale white, with minute dark gray flecks present in the vocal sac region. Details of these measurements are provided in Table 3.

  

Figure 5. Holotype of Raorchestes rezakhani sp. nov. A dorsal view B ventral view C ventral view of right hand D ventral view of right foot E web pattern in foot.

Figure 1. Map showing the type location of Raorchestes rezakhani sp. nov. in northeastern Bangladesh as well as adjoining areas.

Distribution and natural history: Raorchestes rezakhani sp. nov. was recorded from the semi-evergreen forests of northeastern Bangladesh. They were active with the onset of the rainy season in the month of April. We did not hear calls of this species after August. Frogs were found inside the primary and secondary forest mainly on the edge of streams and near man-made trails. They often use the hilly slopes during calling. Individuals perch on leaves and branches of small trees and on bamboo trunks (with diameters of 1.5–4 cm). Vocalizing individuals were perched 1–1.5 m above the forest floor. We usually heard the calls immediately after the sunset (ca. 1815 h in April) although calling activity started a little earlier when it was raining.

 Hassan Al-Razi, Marjan Maria and Sabir Bin Muzaffar. 2020. A New Species of Cryptic Bush Frog (Anura, Rhacophoridae, Raorchestes) from northeastern Bangladesh. ZooKeys. 927: 127-151. DOI: 10.3897/zookeys.927.48733

[Herpetology • 2016] Glaciations, Gradients, and Geography: Multiple Drivers of Diversification of Bush Frogs in the Western Ghats Escarpment

Figure 2. Geographical ancestral range reconstruction on a chronogram of Western Ghats bush frogs Raorchestes shows two sister clades, North and South, divided by an ancient barrier, the Palghat Gap (PG), with limited dispersal (see map). The range on the map does not incorporate dispersal across the PG and an isolated lineage from one of the eastern massifs. Inset map shows global geographical extent of the lineages used in the reconstruction. 

Abstract

The historical processes underlying high diversity in tropical biodiversity hotspots like the Western Ghats of Peninsular India remain poorly understood. We sampled bush frogs on 13 massifs across the Western Ghats Escarpment and examined the relative influence of Quaternary glaciations, ecological gradients and geological processes on the spatial patterns of lineage and clade diversification. The results reveal a large in situ radiation (more than 60 lineages), exhibiting geographical structure and clade-level endemism, with two deeply divergent sister clades, North and South, highlighting the biogeographic significance of an ancient valley, the Palghat Gap. A majority of the bush frog sister lineages were isolated on adjacent massifs, and signatures of range stasis provide support for the dominance of geological processes in allopatric speciation. In situ diversification events within the montane zones (more than 1800 m) of the two highest massifs suggest a role for climate-mediated forest-grassland persistence. Independent transitions along elevational gradients among sub-clades during the Miocene point to diversification along the elevational gradient. The study highlights the evolutionary significance of massifs in the Western Ghats with the high elevations acting as centres of lineage diversification and the low- and mid-elevations of the southern regions, with deeply divergent lineages, serving as museums.

KEYWORDS: diversification; bush frogs; Western Ghats; Earth processes

Figure 1. Alternative processes driving diversification in a mountain setting and expected patterns of sister-lineage distributions (summarized in the electronic supplementary material, table S1). 

S. P. Vijayakumar, Riya C. Menezes, Aditi Jayarajan and Kartik Shanker. 2016. Glaciations, Gradients, and Geography: Multiple Drivers of Diversification of Bush Frogs in the Western Ghats Escarpment. Proc. R. Soc. B 283: 20161011.  DOI: 10.1098/rspb.2016.1011

An evolutionary museum of bush frogs - Nature India DOI: 10.1038/nindia.2016.105