Polypedates jerdonii Günther, 1876: 571.

Rhacophorus jerdonii — Boulenger (1882): 80; Das and Dutta (1998): 67.

Rhacophorus (Rhacophorus) jerdonii — Ahl (1931): 114; Dutta (1997): 101.

Rhacophorus (Rhacophorus) buergeri jerdonii — Wolf (1936): 172.

Philautus (Kirtixalus) jerdonii — Dubois (1987): 73.

Philautus (Philautus) jerdonii — Bossuyt and Dubois (2001): 25.

Philautus sahai Sarkar & Ray, 2006: 303.

Pseudophilautus sahai — Li et al. (2009): 519.

Philautus sahai — Ahmed et al. (2009): 16.

Raorchestes sahai — Biju et al. (2010): 1120.

Frankixalus jerdonii — Biju et al. (2016): 6–13.

Nasutixalus jerdonii — Sivongxay et al. (2016): 439–440.

Raorchestes sahai (Fig. 7) was originally described as Philautus sahai by Sarkar and Ray (2006) based on two specimens collected by S. S. Saha on 29 February 1988 from 10 km north of Gandhigram, Changlang District, Arunachal Pradesh, India. After Biju et al. (2010), this species was placed under Raorchestes by implication (Frost 2025). Since its description, this species has not been reported from the type locality and no attempt has been made to study the types or compare them with other species in Raorchestes or other genera of small rhacophorids. We examined the type series (ZSIA8500 and ZSIA8501) available at the Zoological Survey of India, Kolkata. Our examination of the types revealed some characteristics that contradict the original description of the species by Sarkar and Ray (2006), such as vomerine teeth present in both types although underdeveloped (vs. vomerine teeth absent in original description) (Fig. 7); snout truncated in dorsal and lateral view, rounded in ventral view (vs. snout rounded in original description); rudimentary webbing present on hand (vs. not mentioned in original description). Thus, presence of vomerine teeth in the type specimens suggest that this species does not belong to the nominal genus Raorchestes. Between the years 2022 and 2023, we collected three rhacophorid specimens from Gandhigram that morphologically correspond to the type specimens of R. sahai based on the following set of characters such as truncated snout, protruding eyes, vomerine teeth present, tympanum distinct, rudimentary webbing present on hand, webbing well developed on foot, disc on fingers and toes, abdomen and thigh granular (Figs 7 and 8).

Furthermore, in our phylogenetic analysis (ML) based on the 16S mitochondrial gene, the newly collected samples (of both subadult and adult) formed a clade with Nasutixalus jerdonii (Günther, 1876) from northeast India (Fig. 8A). The uncorrected p distance between the newly collected samples and available sequences of N. jerdonii from India included in this study are 0.0–0.2% in the 16S gene (Table S10).

We also examined the type specimens of N. jerdonii at the Natural History Museum, London collection (BMNH1947.2.7.84 and BMNH1947.2.7.85). Our topotypes agreed with the N. jerdonii types based on the following set of morphological characters: 1) snout rounded or almost truncate in dorsal view and nearly vertical in lateral view; 2) tympanum distinct; 3) small webbing present on hand; 4) circum-marginal groove present on finger and toe disc; 5) toe webbing moderate; 6) granular belly and ventral aspect of thigh; 7) dark patch covering posterior part of head on dorsal aspect, continuing to dorsum and posteriorly bifurcate. The following exceptions or variations were observed in the newly collected material and previously published descriptions. Biju et al. (2016) mentioned that vomerine ridges present in two oblique series without teeth. However, the original description mentioned that vomerine teeth are present. Based on our specimens collected from different parts of northeast India (Meghalaya, Mizoram, and Arunachal Pradesh), most of the specimens of N. jerdonii have blunt vomerine teeth on two oblique series. In some other specimens (for example WII-ADA3240) which is genetically similar, vomerine ridge is present without teeth. Additionally, Jiang et al. (2016) mentioned that vomerine teeth are present in N. medogensis Jiang, Wang, Yan & Che, 2016, while Yang and Chan (2018) mentioned vomerine ridge present without teeth in N. yingjiangensis Yang & Chan, 2018. Thus, this character is not consistent within the genus and species. Biju et al. (2016) mentioned that metacarpal tubercles are absent. However, metacarpal tubercles are visible in the types as well as in our newly collected specimens. Based on the morphological similarity of the topotypes to the holotype and paratype and the phylogenetically close position of the topotypes to N. jerdonii, we consider “R. sahai” to be a junior subjective synonym of N. jerdonii. However, none of the available DNA sequences of N. jerdonii by Biju et al. (2016) and Muansanga et al. (2022) are from the type locality in Darjeeling. Those available sequences are from the hill ranges of the southern slope of the Brahmaputra Valley. Therefore, topotypic samples are needed to determine whether N. jerdonii sensu stricto from Darjeeling and the populations from south of Brahmaputra Valley currently referred to as N. jerdonii belong to the same species or represent different species.

Sarkar and Ray (2006) placed this species in the genus Philautus probably because of the small body size of the collected material. Although Sarkar and Ray (2006) referred to the type series as adults, we confirmed that the types are subadults based on the newly collected subadult and adult specimens from the type locality at Gandhigram. Additionally, this species was never compared with N. jerdonii in the past probably because both the species were placed in different genera. For taxonomic stability, we provide here an expanded description of N. jerdonii based on the newly collected material from the type locality of “R. sahai”.

A subadult female (WII-ADA1770) and an adult male (WII-ADA1773) collected by BB, AD and NGP on 16 September 2022 at Gandhigram (27.265139°N, 96.937041°E, elevation 1120 m a.s.l.), Changlang District, Arunachal Pradesh; an adult male (WII-ADA3240) collected from same locality by AD, SD, RNV and JDG on 23 May 2023.

Medium sized rhacophorid frog, SVL 41 mm; head slightly wider than long (HW/HL = 0.98); snout rounded in dorsal and semicircular in ventral view, vertical in lateral view; snout length smaller than eye length (SL/EL = 0.9); canthus rostralis indistinct, oblique; loreal concave; nostrils oval, laterally positioned and obliquely oriented; nostril closer to snout tip than eye; snout anteriorly depressed at internarial space; internarial space equal to inter-upper eyelid width and upper eyelid width; eyes protruding, moderate in size, less than half of head length (EL/HL = 0.42); tympanum distinct, round, nearly half of eye length (HTYD/EL = 0.47); tongue posteriorly notched; choanae round; vomerine teeth present between choanae and angular to body axis; a pair of internal vocal sac openings on lower jaw; habitus stout, its length nearly half of snout-vent length (AG/SVL = 0.47).

Forelimbs slender; forearm length smaller than hand length (FAL/HAL = 0.71); third finger longest; fingers with rounded disc; disc on third and fourth finger nearly equal to tympanic diameter; circum-marginal groove present on disc; subarticular tubercles rounded and distinct; supernumerary tubercles present; palmar tubercles distinct, oval shaped; rudimentary webbing present between fingers; nuptial pad not visible.

Hindlimbs comparatively stout; thigh length and tibia length equal, less than half of snout-vent length (TL/SVL = 0.43); foot length greater than thigh and tibia length (TL/FOL = 0.96); fourth toe longest; toes with rounded discs; toe discs width slightly smaller than that of fingers; circum-marginal groove present on discs; subarticular tubercles distinct and rounded; supernumerary tubercles absent; inner metatarsal tubercle present; outer metatarsal tubercle absent; webbing moderate, reaching first subarticular tubercle on fourth toe.

Skin on dorsal aspect of snout and head smooth with numerous enlarged, distinct spinules including on upper eyelids; similar spinules on loreal region, below eyes, and on mandibular region; skin on dorsum smooth with numerous spinules, which decrease in number posteriorly; flank with flat granular tubercles; ventrum of head and chest smooth; abdomen granular; granules on thigh indistinct; flat tubercles below vent; forelimbs, tibia, and tarsus smooth.

Top and lateral sides of head brown; tip of snout with enlarged olive-brown patch to below nostrils and vertical pale yellow line at tip of snout; a similarly coloured spot in front of interorbital space; olive-brown stripe on loreal region below canthus rostralis; a similarly coloured patch below eyes, bordered with pale yellow; dark brown iris with irregular golden patches; olive-brown streak along anterior part of supratympanic fold and a few irregular spots on tympanum; dorsum pale yellowish brown with enlarged olive brown hourglass shaped patch, starting from interorbital space and covering posterior half of upper eyelids, posteriorly bifurcating in middle of dorsum, directing towards groin as gradually diffusing; two pale yellowish brown spots on dark patch, one on back of head and another elongated one on anterior part of back; flank pale brown with some irregular small olive-brown spots; dorsum of forelimb pale yellowish brown; broad olive-brown band on forearm; similar patch on base of hands and dorsal aspect of fingers; hindlimbs pale yellowish brown on top with three broad olive-brown, irregular bands on each thigh and tibia; small patch of similar colour on knees; similar bands on tarsus, base of foot, and on dorsal aspect of toes; ventrum of head, abdomen, and limbs uniform pale cream coloured.

Dorsal aspect of head, dorsum, and limbs brown; markings on head, dorsum, and limbs visible as in life; ventrum of head, back and limbs uniform pale brown.

Overall, the newly collected material from the type locality of “R. sahai” similar to the types of N. jerdonii. However, following variations were observed among the individuals. Head slightly wider than length in WII-ADA1773 which is similar to that of holotype of “R. sahai” (ZSIA8500). However, in the paratype (ZSIA8501) and two newly collected specimens (WII-ADA3240 and WII-ADA1770), head length is equal to head width. Snout length is equal to eye length in the type specimens of “R. sahai” (ZSIA8500, ZSIA8501), but slightly shorter in the newly collected specimens. Snout length greater than eye length in the types of N. jerdonii (BMNH 1947.2.7.84, BMNH 1947.2.7.85). Inter-upper eyelid width greater than upper eyelid width in the types of “R. sahai” (ZSIA8500, ZSIA8501) and types of N. jerdonii (BMNH 1947.2.7.84, BMNH 1947.2.7.85). Inter-upper eyelid width is equal to the upper eyelid width in WII-ADA1773 and in two specimens (WII-ADA3240 and WII-ADA1770), inter-upper eyelid width is smaller than upper eyelid width. Internarial distance equal to inter-upper eyelid width in the types of “R. sahai” (ZSIA8500, ZSIA8501) and WII-ADA1773. Internarial distance equal to inter-upper eyelid width in the types of “R. sahai” (ZSIA8500, ZSIA8501) and WII-ADA1773 while internarial distance greater than inter-upper eyelid width in WII-ADA3240 and WII-ADA1770. Internarial distance smaller than inter-upper eyelid width in the types of N. jerdonii (BMNH 1947.2.7.84, BMNH 1947.2.7.85). Tibia length smaller than thigh length in types of “R. sahai” (ZSIA8500, ZSIA8501) and the two topotypes (WII-ADA3240 and WII-ADA1770) but thigh length and tibia length equal in WII-ADA1773. Tibia length greater than thigh length in the types of N. jerdonii (BMNH 1947.2.7.84, BMNH 1947.2.7.85). A detailed morphometric variation of the newly collected material is provided in Table S11. Dorsal markings on head, dorsum and limbs of the types are barely visible unlike the topotypes. In addition, WII-ADA3240 has a distinct nuptial pad on the first finger; irregular shaped and sized brown patches present on ventrum of head, chest, and forelimbs of WII-ADA1770.

Nasutixalus jerdonii is widely reported from northeast India (Biju et al. 2016). It was previously reported from Darjeeling (Günther 1876); Mawphlang Sacred Grove, Wahlynkien (Marai Kaphon), Cherrapunji in Meghalaya; Zaraengtung, Raenghzaeng Village in Manipur; Sechüma village, Zubza, Meriema Village, Seukwehii, Tseminyu Village in Nagaland (Biju et al. 2016); Hmuifang Community Reserve Forest, Murlen National Park in Mizoram (Muansanga et al. 2022). Rahman et al. (2020) reported this species from Ziradum, Myanmar. Zug (2022) reported this species from northern Myanmar (Kachin). During our study, we recorded the species from Gandhigram and near Glaw Lake at Kamlang Tiger Reserve in Arunachal Pradesh, and in Hmuifang, Mizoram. At Gandhigram, subadult individuals were recorded on leaves at a height of ~20 cm above ground near a small stream ~300 cm wide at around 20:00 hrs. Adult individuals were recorded on leaves at a height of ~100 cm above ground at around 22:00 hrs in September 2022. Calling males were observed active among tree ferns at three meters above ground in late May.

Rhacophorus microdiscus Annandale, 1912: 114.

Rhacophorus (Rhacophorus) microdiscus — Ahl (1931): 57, 121.

Philautus (Kirtixalus) microdiscus — Dubois (1987): 73.

Philautus (Philautus) microdiscus — Bossuyt and Dubois (2001): 40.

Philautus microdiscus — Ahmed et al. (2009): 16.

What is currently known under Philautus microdiscus (Fig. 9) was originally described by Annandale (1912), based on a single specimen (ZSI16924), as Rhacophorus microdiscus from Kobo in the foothills of Abor (now in Assam; Fig. 1A). This species has never been reported since its description. Gorham (1974) synonymized this species with Rhacophorus jerdonii (now Nasutixalus jerdonii) but this was not followed by Dubois (1987) and Bossuyt and Dubois (2001). Gorham (1974) was only followed by Sarkar and Ray (2006). Dubois (1987) placed this species in the genus Philautus under the subgenus Kirtixalus. Later, Bossuyt and Dubois (2001) transferred it to the nominotypical subgenus Philautus. However, Garg et al. (2021) questioned the placement of this species in the genus Philautus. Based on molecular data of bush frogs collected from across northeast India, we argue that there are no species of the genus Philautus (sensu stricto) present in this region.

After a review of Annandale’s original description and examination of the holotype (ZSI16924) we provide the following characters for the holotype: small body size (28.7 mm); presence of vomerine teeth; presence of rudimentary webbing on hand; presence of discs on digits. Annandale (1912) mentioned that the disc on the third finger is less than half of the tympanic diameter, but this may be because the specimen was in a dehydrated state as seen on the sketch provided in the original description); granular abdomen and thighs; subtriangular marking on head; concave stripes on dorsum; crossbars on dorsal surface of limbs (Fig. 9); lateral sides of thighs reddish (based on original description).

The holotype being a small bodied frog (28.7 mm) with a comparatively short rounded snout and discs on the fingers and toes (as with species in Nasutixalus, Philautus, Pseudophilautus, and Raorchestes), from northeast India (as we argue only with Nasutixalus and Raorchestes) with vomerine teeth (absent in Raorchestes) strongly suggests that “P. microdiscus” belongs to the genus Nasutixalus Jiang et al., 2016. Species of the genus Nasutixalus (e.g., N. medogensis) are known to occur in the Adi (= Abor) Hills of Arunachal Pradesh (Biju et al. 2016; Yang et al. 2018). During our field surveys over the past five years we recorded several populations of Nasutixalus in the upper reaches of the Adi Hills and throughout the State of Arunachal Pradesh. These recorded specimens partially match Annandale’s description by the following set of characters: dorsally rounded and laterally nearly truncate snout shape, distinct canthus rostralis, presence of vomerine teeth, distinct tympanum, presence of dorsal stripes, presence of dark bar on inter-upper eyelid space, crossbars on limbs, granular belly, discs on fingers, webbing on foot. Thus, we formally transfer Philautus microdiscus to Nasutixalus microdiscus nov. comb. but acknowledge that further studies involving collecting specimens from the type locality or near the type locality of N. microdiscus and including molecular data for phylogenetic comparisons will be necessary to confirm the identity of these records. In addition, the type localities of N. microdiscus and N. medogensis are 90 km apart. Therefore in the light of these new findings, the identity of N. medogensis needs to be verified. Morphometric measurements of holotype of N. microdiscus taken in this study are provided in Table S11.

In the original description, the type locality was given as “Kobo, at the base of Abor foothills”. However, species of the genus Nasutixalus are known to occur above 1000 m elevation, while the elevation of Kobo (present day) is below 150 m a.s.l. (Bossuyt and Dubois 2001). It is possible that the specimens were collected from the hills immediately above Kobo in Adi Hills. Fresh material from the area or DNA from the type specimen will help to resolve the true identity of this species.

Megalophrys kempii Annandale, 1912: 20.

Panophrys kempii — Rao and Yang (1997): 98–99.

Megophrys (Xenophrys) kempii — Dubois and Ohler (1998): 14.

Megophrys kempii — Fei (1999): 116.

Xenophrys kempii — Ohler (2003): 23.

Philautus kempii — Delorme et al. (2006): 17.

Aquixalus kempii — Fei et al. (2009): 17.

Liuixalus kempii — Fei et al. (2012): 512.

Philautus kempii (Fig. 10) was originally described as Megalophrys kempii from Rotung (= Rottung), Arunachal Pradesh based on a single specimen (Annandale 1912). Since its description this species has never been reported from the type locality. However, it was transferred to megophryid (Rao and Yang 1997; Dubois and Ohler 1998; Fei 1999; Ohler 2003) and rhacophorid genera (Delorme et al. 2006; Fei et al. 2009, 2012) by implication. Delorme et al. (2006) placed this species in the genus Philautus based on characters such as granular abdominal skin and indistinct digital discs, and this combination has been followed subsequently (Zug 2022; Frost 2025).

Our observation of the holotype (ZSI17013) (Fig. 10) showed that it has a distinct and enlarged tympanum with a diameter of 70% of the eye length, located close to the eye, which is also mentioned in the original description (Annandale, 1912). Based on characters such as 1) small body size (SVL 14.8 mm), 2) large tympanum, 3) absence of vomerine teeth, 4) dilated finger and toe tips (Fig. 10E), 5) obscurely granular abdomen, 6) rudimentary webbing on foot, 7) fourth toe much longer (Fig. 10E), 8) granules on lateral side of thigh towards vent, 9) subarticular tubercles not much pronounced, 10) crossbands on hindlimbs, we argue that the nomen is not a rhacophorid but resembles the ceratobatrachid genus Liurana Fei, Ye & Huang, 1997. Although Annandale (1912) mentioned metacarpal tubercles and metatarsal tubercles absent (vs. present in Liurana), supratympanic fold absent (distinct or indistinct in Liurana), we could not study much of the characters of the holotype as it is dehydrated and the limbs are damaged (Fig. 10). The dorsal colouration of the specimen could not be determined, but the colouration in Liurana is variable (personal observation). Morphometric measurements of the holotype are provided in Table S11.

The absence of vomerine teeth and a granular abdomen are characteristics of Raorchestes (Biju et al. 2010). So far, we have not recorded any species of Raorchestes with an enlarged tympanum like ZSI17013. On the other hand, granular abdomen and thighs are not characters of Megophrys or Xenophrys. Furthermore, we have not recorded any Xenophrys species with an enlarged tympanum close to the eye. Mahony et al. (2013, 2018, 2020) did not report this condition in any species in their revisions. Additionally, the holotype of P. kempii does not have characters that match with characters of other known genera of Megophryidae from the Eastern Himalayas such as Scutiger Theobald, 1868 and Leptobrachium Tschudi, 1838 by: 1) absence of axillary and pectoral glands (present in Scutiger); 2) absence of keratinised warts on dorsum (vs. present in Scutiger); 3) absence of shovel shaped inner metatarsal tubercle (present in L. bompu Sondhi & Ohler, 2011 known from Arunachal Pradesh); 4) presence of enlarged tympanum (vs. tympanum indistinct if present in L. bompu). Also, even though small bodied species of Leptobrachella are known from the hills south of Brahmaputra Valley [i.e., L. khasiorum (Das, Tron, Rangad & Hooroo, 2010) and L. nokrekensis (Mathew & Sen, 2010) from Meghalaya, L. lateralis (Anderson, 1871) from Nagaland, and L. tamdil (Sengupta et al., 2010) from Mizoram and Manipur], the genus Leptobrachella has not been reported from Eastern Himalayas. However, recent studies have reported Liurana species (L. himalayana Saikia & Sinha, 2019, L. indica Saikia & Sinha, 2019, L. medogensis Fei, Ye & Huang, 1997, L. minica Saikia & Sinha, 2019) from the state of Arunachal Pradesh (Saikia and Sinha 2019). During this study, we also observed Liurana spp. from Adi Hills near the type locality, which matches the original description of Philautus kempii as mentioned above. Therefore, based on the original description and the figure and our examination of the type specimen, we formally transfer Philautus kempii to Liurana kempii nov. comb. However, further studies are needed to confirm that L. kempii is not a species of Megophryidae, given that no individuals of megophryids with characters such as small body size with elongated fourth toe and large tympanum have been recorded from this region. Furthermore, it is necessary to confirm whether the specimens of Liurana spp. from the Adi Hills represent L. kempii or a different species of Liurana.

Ixalus jerdonii Günther, 1876: 575.

Rhacophorus dubius Boulenger, 1882: 81.

Rhacophorus (Philautus) dubius — Ahl (1931): 55, 93.

Philautus (Kirtixalus) dubius — Dubois (1987): 73.

Philautus jerdonii — Sarkar et al. (1992): 90.

Rhacophorus dubius — Das and Dutta (1998): 66.

Philautus (Philautus) dubius — Bossuyt and Dubois (2001): 26.

What is currently known as Philautus dubius was originally described as Ixalus jerdonii Günther, 1876 (Fig. 11). Boulenger (1882) replaced its name with Rhacophorus dubius when both Polypedates jerdonii (= Nasutixalus jerdonii) and Ixalus jerdonii were transferred to the genus Rhacophorus. The type locality of this species is still unclear, whether it is Darjeeling, West Bengal or the Khasi Hills, Meghalaya (Günther 1875; Bossuyt and Dubois 2001). Günther (1875) mentioned that although the single specimen of this nomen was from T. C. Jerdon’s collection from Darjeeling, the specimen might have been from Khasi Hills, Meghalaya, which Jerdon (1870) had mentioned. Dubois (1987) placed this species in the genus Philautus solely based on the large depigmented eggs present in the holotype. The taxonomic identity of this species remains unknown (Garg et al. 2021).

The body size (SVL 43.4 mm) of this specimen is larger than any known species of direct developing frogs from northeast India. Furthermore, the specimen has papilla on tongue, dermal fringe present along forearms, and moderate webbing on toes (TII, TIV, TV), and trace of vomerine ridge visible. Therefore this species is a member of other rhacophorid genus and not Philautus. However, fresh samples from the type locality or historical DNA from the type specimen will be helpful to determine the taxonomic identity of this species. In absence of molecular data and topotype, as of now we refrain from transferring the species to any other genus.

Ixalus tuberculatus Anderson, 1879 “1878”: 845.

Rhacophorus andersoni Ahl, 1927: 36.

Rhacophorus (Philautus) andersoni — Ahl (1931): 53, 67.

Philautus tuberculatus — Bourret (1942): 178.

Philautus andersonii — Bourret (1942): 452 (incorrect spelling).

Rhacophorus (Philautus) andersoni — Bourret (1942): 452.

Philautus andersoni — Bourret (1942): 526; Ahmed et al. (2009): 15.

Philautus (Philautus) tuberculatus — Bossuyt and Dubois (2001): 28.

Aquixalus tuberculatus — Fei et al. (2009): 714.

Theloderma andersoni — Li et al. (2009): 520.

Liuixalus tuberculatus — Fei et al. (2012): 513.

Theloderma (Theloderma) andersoni — Poyarkov et al. (2015): 276.

Theloderma tuberculatus — Hou et al. (2017): 114.

Raorchestes andersoni — Chen et al. (2020): 4.

Raorchestes andersoni was originally described by Anderson in 1879 “1878” as Ixalus tuberculatus from Nampoung [= Nanben River] in the centre of the Kakhyen Hills, Yingjiang County, Yunnan, China (Hou et al. 2017). Ahl (1927) gave the replacement name as Rhacophorus andersoni for the nomen I. tuberculatus, as it became a secondary homonym of Polypedates tuberculatus Anderson, 1871, when both species (I. tuberculatus and P. tuberculatus) were placed in the genus Rhacophorus (see Frost 2025). Bourret (1942) placed this species under the genus Philautus without discussion of Ahl’s (1931) placement of this species under the genus Rhacophorus and subgenus Philautus. Li et al. (2009) placed this species in the genus Theloderma Tschudi, 1838 mentioning its morphological similarity to T. albopunctatum (Liu & Hu, 1962) without further discussion. Later Hou et al. (2017) obtained topotypic specimens of this species and reallocated them to the genus Raorchestes. Hou et al. (2017) provided a photograph of the species and mentioned morphological similarity with topotypic specimens of R. longchuanensis (Yang & Li, 1978) but did not provide a description. Subsequently, Chen et al. (2020) supported this reallocation by Hou et al. (2017) and provided a phylogenetic status of R. andersoni. However, Chen et al. (2020) did not mention about the locality of the sample they referred to as R. andersoni. Raorchestes andersoni has never been reported from the type locality since its original description until Hou et al. (2017) reported it, and the type specimen, which was deposited in the Zoological Survey of India, Kolkata is presumed lost (Bossuyt and Dubois 2001; Frost 2025).

It is worth mentioning that the original sketch of the species provided by Anderson (1878) and, the original description of “I. tuberculatus” (on page 845 of Anderson 1878) does not correspond to the sketch provided in figure 7 of plate LXXVIII of Anderson (1878), as reproduced in Figure 12 here. Instead, it corresponds to “fig. 6” on the same plate named as “I. kakhienensis”, which was also described in the same communication (page 845 of Anderson 1878). The latter species (I. kakhienensis) is now a tentative synonym of Amolops afghanus (Gunther, 1858) (Dever et al. 2012; Frost 2025). In the original description of “I. tuberculatus” Anderson stated “a transverse pale yellowish band between the eyes and two similar bands behind the eyes”. However, this is not shown in “fig. 7”, but two white bars are clearly visible in “fig. 6” and the original description mentioned “A large black irregular spot on the groin, extending halfway up the side with two yellow spots, the thigh broadly but obscurely banded with dark brown and yellow, one broad band across the middle of the thigh and lower leg”. But there is no large black irregular spot visible on the groin in “fig. 7” and more than one broad band is clearly present on the thigh and tibia of “fig. 7”. However, the sketch of “fig. 6” has at least one broad band visible on the thigh and tibia. In addition, the original description of the species stated that the hindlimbs are very weekly webbed, with the webbing only extending to the end of the first phalanx. However, more extensive webbing can be seen in “fig. 7” but not in “fig 6”. Thus, a redescription (in which the text matches an image) of the species based on fresh material from the type locality will be helpful in stabilising the taxonomic identity of this species.

Annandale (1912) reported Raorchestes andersoni from the Adi Hills (Abor Hills), Arunachal Pradesh, India based on morphology. Bourret (1942) discussed the dissimilarity of Annandale’s specimen with the original description. We now refer to this population from Adi Hills as a new species described below. Recently, a few species of Raorchestes have been described from the nearest locality to the type locality of R. andersoni in Yunnan, such as R. hillisi Jiang et al., 2020, R. huanglianshan Jiang et al., 2020, and R. dulongensis Wu et al., 2021. However, none of these authors discussed the phylogenetic status of R. andersoni. Che et al. (2020) provided a record and phylogenetic status of R. andersoni as “Raorchestes cf. tuberculatus” from Tibet. Sen and Mathew (2008) reported one specimen from Nagaland and claimed its distribution in much of northeast India (Arunachal Pradesh, Assam, Meghalaya, Mizoram). Later, Mathew and Sen (2010) provided photographs of a specimen of Philautus andersoni and maintained its distribution in northeast India (Arunachal Pradesh, Assam, Meghalaya, Mizoram), but did not include Nagaland in its distribution. Wangyal and Jamtsho (2022) reported R. andersoni from Bhutan based on photographs. Since there is still no molecular data available from an individual from the type locality that matches the original description of this species, these records require further verification and may represent some undescribed species or one of our newly described species from this region.

Philautus tytthus Smith, 1940: 475.

Philautus tytthus — Bossuyt and Dubois (2001): 52; Zug (2022): 42.

Philautus tytthus (Fig. 13) was described by Smith (1940) based on two specimens collected by R. Kaulback from Htingnan, Kachin, northern Myanmar. Since its description, this species has never been reported from the type locality and the phylogenetic status of the species remains unknown. We examined the type series (BMNH 1947.2.5.92–93) of this species at the Natural History Museum London (NHM). Based on the following combination of morphological characters, and geographical distribution of Philautus sensu stricto, we propose that this species be considered as a member of the genus Raorchestes and no other rhacophorid genus based on the following characters: 1) SVL 20.9–21.2 mm, 2) absence of vomerine ridge or teeth, 3) absence of serrated dermal fringe along forearms and tarsus, 4) absence of light coloured dorsolateral stripes along the dorsum, and 5) absence of calcar. Thus, we transfer Philautus tytthus to Raorchestes tytthus nov. comb.

Ixalus cinerascens Stoliczka, 1870: 275.

Ixalus cinerascens — Sclater (1892a): 347; Sclater (1892b): 20; Annandale (1908): 305.

Rhacophorus (Philautus) cinerascens — Ahl (1931): 75.

Philautus cinerascens — Broadley (1971): 112; Chanda et al. (2000): 112; Zug (2022): 42.

Philautus (Philautus) cinerascens — Bossuyt and Dubois (2001): 23.

Philautus cinerascens (Fig. 14) was described by Stoliczka (1870) based on specimens collected by W. Theobald from “Atran River, east of Moulmein (Tanintharyi Division)”, Myanmar. Annandale (1913) mentioned the type locality as “probably the Dawna Hills inland from Moulmein”. Since its description, there is no further report of this species from the type locality. The original voucher numbers for the specimens were not mentioned in Stoliczka (1870). Stoliczka (1872) mentioned that this species was described based on two specimens from Moulmein. However, Chanda et al. (2000) mentioned that there are four syntypes under the number “ZSIC 2716”. Although this species was described based on multiple specimens (Bossuyt and Dubois 2001), only a single type specimen is mentioned in the literature (e.g., Anderson 1871; Sclater 1892a, 1892b; Annandale 1908, 1913). Sclater (1892b) gave the voucher number “2716” and called it the “type of the species”. We found four specimens (Fig. 14) with the same voucher number “ZSI 2716” at ZSI, Kolkata. As these specimens are in a bad state of preservation, only a few characters could be examined. Among the four specimens, the largest specimen (SVL 16 mm) can be assigned to the genus Raorchestes based on the following morphological characters and geographical distribution of Philautus sensu stricto: 1) vomerine teeth absent, 2) absence of serrated dermal fringe along forearms and tarsus, 3) absence of light coloured dorsolateral stripes along the dorsum, 4) absence of calcar. The original description corresponds to this specimen, where Stoliczka (1870) mentioned the size of this specimen as “¾ of an inch” and as the largest of the specimens. Sclater (1892a) and Annandale (1913) also mentioned this specimen as “a true Ixalus”. However, the other three specimens differ from the “type” and no doubt belong to one or more rhacophorid genera but not Raorchestes or Philautus. These three specimens have smooth skin on the dorsal surface of the head, dorsum, and limbs; abdominal skin indistinctly granular; thigh ventrally smooth. Most importantly, these three specimens have much longer hind limbs. One which we measured (Fig. 14G, H) has a femur length 60% of the SVL (13.9 mm) and a tibia length of 62% of SVL. At this stage it is not possible to assign these three specimens to any genus due to the condition of the specimens. We propose to consider the largest type specimen (ZSI 2716) as Raorchestes (Fig. 14E, F) which corresponds to the original description, and because Sclater (1892a) and Annandale (1913) referred to this specimen as the type for the nomen and as a “true Ixalus”. Thus, based on the above-mentioned morphological characteristics, we transfer Philautus cinerascens to Raorchestes cinerascens nov. comb. Consequently, we designate this specimen as the lectotype for Raorchestes cinerascens nov. comb. However, the status of the other three specimens will remain pending. To stabilize the taxonomy of this specimen and the other three syntypes, a redescription based on the newly collected material from the type locality is necessary.

Small sized Raorchestes, SVL 16 mm (Fig. 14E, F); lower jaw broken anteriorly; both the forelimbs broken at elbow; left hind limb broken at groin and tibiotarsal articulation; right hindlimb broken at knee and toes completely damaged; longitudinal incision on belly. Snout rounded in dorsal and ventral aspect; canthus rostralis indistinct; vomerine ridge or teeth absent; tympanum indistinct; supratympanic fold distinct; finger disc rounded, circummarginal groove present; thigh length slight greater than tibia length (TBL/TL = 0.98); toe disc rounded, with circummarginal groove; skin on dorsal aspect of head, dorsum and limbs smooth; a few indistinct tubercles on upper eyelids and posterior part of head behind upper eyelids; on ventral aspect, gular region and chest smooth; belly and thigh granular; tibia smooth on ventral aspect.

Dorsal aspect of head, dorsum and limbs brown, slightly paler towards flank and base of the hindlimb; ventral aspect nearly uniform brown but slightly paler than the dorsal colour. Except slightly dark patch on groin and slightly dark and single broad cross bar on thigh and tibia, other colour pattern such as dark bar on inter-upper eyelids space, stripes on dorsum; bands on forearms, silvery tinge encircling dark patch on groin as mentioned in the original description are not visible now.

Ixalus garo Boulenger, 1919: 207.

Rhacophorus (Philautus) garo — Ahl (1931): 70.

Philautus garo — Bourret (1942): 450–451; Inger (1985): 528; Ahmed et al. (2009): 15.

Philautus (Philautus) garo — Bossuyt and Dubois (2001): 41.

Philautus namdaphaensis Sarkar and Sanyal, 1985: 287–289.

Raorchestes manipurensis Mathew & Sen, 2009: 43, 44, plate XVI.

Philautus namdaphaensis — Ahmed et al. (2009): 16, 147.

Raorchestes cangyuanensis Wu et al., 2019: 558–561.

Raorchestes kempiae — Naveen et al. (2024): 362, 365–367.

Raorchestes garo — Naveen et al. (2024): 362.

Boulenger (1919) described “Ixalus” garo based on a single specimen (Fig. 15 A–D) collected by Stanley Wells Kemp from “above Tura”, Garo Hills. It was subsequently placed in other rhacophorid genera including Rhacophorus Kuhl & van Hasselt, 1822 and Philautus (Ahl 1931; Bourret 1942; Inger 1985; Bossuyt and Dubois 2001). This species has been reported from Assam (Choudhury et al. 2001), Nagaland (Ao et al. 2003) and Shillong in Meghalaya (Mathew and Sen 2009; Kharkongor et al. 2016). However, it has never been reported from its type locality (above Tura in Garo Hills, Meghalaya) since it was first described. Recently, Naveen et al. (2024) reported this species from Daribokgre Community Reserve in the East Garo Hills District of Meghalaya, claiming that their collected specimen is a “topotype” (see discussion below). During our field survey on 27 May 2022, we encountered an individual of the bush frog (Fig. 16A–H) at the type locality Tura Peak (25.50302°N, 90.23853°E, elevation 1030 m a.sl.), Meghalaya. These individuals resemble the characters mentioned in the original description of R. garo by Boulenger (1919) as follows: 1) dark-brown hourglass shaped mark covering head from interorbital space and back, 2) loreal and temporal region dark-brown, 3) dark-brown crossbars on limbs and 4) distinct tympanum, 5) canthus rostralis distinct. Although the original description stated the snout shape is truncated, it is damaged in the holotype (squeezed, see Fig. 15). Our examination of the newly collected material found that the snout shape is rounded or sub-ovoid.

Holotype: ZSI 19187, subadult (sex could not be determined); collected by S.W. Kemp above Tura, West Garo Hills District, Meghalaya, India.

Topotypes: five adult males (WII-ADA1493–1496, WII-ADA1499) collected by BB, VJ, and AD on 27 May 2022 from Tura Peak Reserved Forest (25.50302°N, 90.23853°E, elevation 1030 m a.s.l.), West Garo Hills District, Meghalaya. Referred materials: one adult male (WII-ADA1479) collected by BB, VJ, and AD on 20 May 2022 from Daribokgre (25.48973°N, 90.32373°E, elevation 1140 m a.s.l.), West Garo Hills District, Meghalaya; two adult males (WII-ADA858, WII-ADA859) collected by BB and AD on 1 August 2021 from near Kiphire Divisional Forest Complex (25.89940°N, 94.76947°E, elevation 1300 m a.s.l.), Kiphire District, Nagaland; one adult male (WII-ADA861) collected by BB and AD on 2 August 2021 from Aramasangram, (25.83128°N, 94.87319°E, elevation 1480 m a.s.l.), Kiphire District, Nagaland; seven adult males (WII-ADA601–WII-ADA605, WII-ADA607, WII-ADA608) collected by BB on 18 April 2019 from Lakhicherra (24.97502°N, 92.77305°E, elevation 50 m a.sl.), Cachar District, Assam; two adult males (WII-ADA609, WII-ADA610) collected by BB on 20 April 2019 from Subhang (24.97613°N, 92.79206°E, elevation 170 m a.s.l.), Cachar District, Assam; two adult males (WII-ADA1035 and WII-ADA1036) collected by BB, NGP, and AD on 9 September 2021 from Ngengpui Wildlife Sanctuary (22.48696°N, 92.77307°E, elevation 180 m a.s.l.), Lawngtlai District, Mizoram; one adult female (WII-ADA1142) collected by BB, NGP, and AD on 16 September 2021 from Teirei (23.694°N, 92.45147°E, elevation 270 m a.s.l.), Dampa Tiger Reserve, Mamit District, Mizoram; one adult male (WII-ADA1645) collected by BB on 25 July 2022 from Leimatak (24.59375°N, 93.66256°E, elevation 480 m a.sl.), Churachandpur District, Manipur; two adult males (WII-ADA1648 and WII-ADA1649) collected by BB on 26 July 2022 from Charoikhullen (24.6071°N, 93.71986°E, elevation 1180 m a.s.l.), Churachandpur District, Manipur; four adult males (WII-ADA3211, WII-ADA3213, WII-ADA3217, and WII-ADA3219) collected by RNV and SD on 9 May 2023 from Haldibari (27.52453°N, 96.39913°E, elevation 500 m a.s.l.), Namdapha Tiger Reserve, Changlang District, Arunachal Pradesh.

Small to medium sized Raorchestes, SVL 19.9–26.9 mm in adult males; head length equal to its width or slightly wider than long (HL/HW = 0.9–1.01); snout shape rounded to sub-ovoid in dorsal view, snout length slightly less than or equal to eye length (SL/EL = 0.81–1.03); snout length greater than or equal to inter-upper eyelid width (0.96–1.28); nostrils closer to snout tip than eye or equidistant between the two; internarial distance smaller than inter-upper eyelid width (IN/IUE = 0.71–0.94) and greater or equal to upper eyelid width (UE/IN = 0.73–1.0), inter-upper eyelid width smaller than eye length (0.74–0.94); spinules or tubercles on dorsum; brown patches on groin and thigh; three dark bands on thigh and tibia.

Specimen completely dehydrated; snout squeezed; lower jaw broken at right side; fourth finger disc on left side damaged; right hind limb is dislodged from body; a puncture on anterior part of abdomen. Small sized frog (SVL = 12.3 mm); head length equal to width; eyes moderate, less than half of head length (EL/HL = 0.38); interorbital space equal to eye length and greater than upper eyelid width (UEW/IUE = 0.43); tympanum distinct, round; tongue posteriorly notched; supratympanic fold visible; forelimbs slender, forearm length smaller than hand length (FAL/HAL = 0.81); each finger with rounded discs; circum-marginal groove present on discs; subarticular tubercles distinct, rounded; palmar tubercles indistinct; hindlimbs slender, thigh length more than half of snout-vent length (TL/SVL = 0.57) and slightly longer than tibia (TBL/TL = 0.97); each toes with rounded disc; discs with circum-marginal groove, as wide as those on fingers; subarticular tubercles distinct, rounded; inner metatarsal tubercle present and outer metatarsal tubercle absent; dorsal aspect of head and dorsum smooth; dorsal surface of limbs smooth; flank smooth; throat, chest and ventral side of limbs smooth; abdomen granular.

Head dorsally brown and paler laterally; dorsum brown and paler towards the flank; enlarged, slightly darker hourglass shaped mark visible on dorsum starting at interorbital space, posterior ends much darker near groin; limbs brown dorsally; pale brown ventrally; brown specks on throat, chest, and anterior part of abdomen and lower arms.

A medium sized Raorchestes, SVL 25.3 mm; head wider than long (HL/HW = 0.93); snout rounded in dorsal view, slightly protruding beyond lower jaw in ventral view; snout length slightly smaller than eye length (SL/EL = 0.92) and equal to inter-upper eyelid width; a slight depression on internarial space; nostrils oval, obliqued, closer to snout tip than eyes (NS/EN = 0.88); narial region protruding; canthus rostralis distinct, obliqued; loreal region concave; eyes protruding, moderate in size (EL/HL = 0.38), greater than inter-upper eyelid width (IUE/EL = 0.89); internarial distance equals to upper eyelid width; tympanum round, distinct, nearly one fourth of eye length; supratympanic fold distinct; vomerine teeth absent; choanae round; trunk less than half snout-vent length (TRL/SVL = 0.48).

Forelimbs slender; forearm shorter than hand length (FAL/HAL = 0.86); third finger longest; fingers with rounded discs; circum-marginal groove present on discs; disc on finger II, III and IV greater than tympanic diameter; palmar tubercles indistinct; subarticular tubercles distinct, round; proximal subarticular tubercle on finger III and IV smaller than distal subarticular tubercles; fine granular nuptial pad on first finger; webbing absent.

Hindlimbs slender; thigh length half of snout-vent length (TL/SVL = 0.52) and slightly greater than tibia length (TBL/TL = 0.98); fourth toe longest; circum-marginal groove present on toe discs; subarticular tubercles distinct, rounded; proximal subarticular tubercle on fourth toe indistinct and small; supernumerary tubercles absent; toe disc width equal to that of fingers; inner metatarsal tubercle present, its length equal to disc width of second toe; outer metatarsal tubercle absent; webbing small, reaching second subarticular tubercle on fourth toe.

Skin on dorsal aspect of snout and head smooth with indistinct tubercles on upper eyelids; side of head smooth, with few tubercles behind angle of jaw; spinules starting behind upper eyelids and above supratympanic folds runs along dorsolateral side of trunk and scatter on middle of trunk, posterior part of dorsum smooth; flank granular; forelimbs and hindlimbs smooth dorsally; head on ventral side smooth; chest, lower arms, abdomen and thighs granular; tibia smooth.

Dorsal aspect of head yellowish brown from snout to anterior one third of upper eyelids with irregular brown spots; dorsum yellowish brown with dark brown spots; an hourglass shaped brown mark starting from interorbital space covering posterior two third of upper eyelids to anterior to vent, posteriorly diffused; dark brown spots along the edges of hourglass shaped mark; loreal region and area anterior to nasals brown, area below eyes, lips, tympanic region and mandibular region pale brown with slightly dark brown specks and spots; indistinct brown streak below supratympanic fold starting from posterior corner of eyes to rear of mandible; lower arm of forelimbs yellowish brown dorsally and forearm greyish brown dorsally; a brown crossbar on forearms; hands greyish brown with brown specks; disc of the first and second fingers pale yellow; thighs and tibia yellowish brown dorsally; greyish brown with faint reddish tinge towards outer lateral side of tibia and tarsus; indistinct crossbars on tibia; crossbars on thighs in the form of interconnected spots; large dark brown patch on outer lateral side of thighs and inner lateral side of tibia; irregular shaped dark brown enlarged spots on groin and a slightly paler elongated patch ventral to it; faint brown patch on inner lateral side of thighs; a few dark brown spots above vent; throat, chest, abdomen, ventral aspect of forelimbs, and base of thighs flesh coloured; brown mottling and creamy-white spots on anterior part of lower jaw and irregularly shaped small brown patches along its edge; gular region slightly pale yellow; brown specks on anterior part of abdomen, ventral aspect of forelimbs, and palm, heavily speckled on forearms; ventral aspect of foot, tibia, and to distal end of thighs heavily speckled with brown.

Dorsal markings on head, dorsum and flank same as when alive; dorsum of snout pale cream coloured up to interorbital space including anterior part of upper eyelids, a brown patch in the middle; side of head dark brown; dorsum towards flank pale-cream coloured with dark brown spots; the dark brown hourglass shaped mark covering head, and dorsum visible as in life; lower arms cream coloured and forearms dark brown; thighs and tibia cream coloured; outer dorsolateral side of tibia dark brown; tarsus and foot dark brown; distinct dark brown crossbars on thigh and tibia; dark brown marbling on ventral side more distinct than in life, dense marbling on chin, along lower jaw, forearms, chest, tibia, tarsus and foot.

Adult males have external vocal sac, internal vocal slits on lower jaw, and nuptial pad on first finger. Details of variation in morphometric characters among individuals are given in Table S12. In addition, marking patterns on head, dorsum, groin and thigh vary among individuals of the species (Figs 16, 17). Dorsal colour varies as pale yellowish brown, pale reddish brown and greyish brown. Hourglass shaped marking dark grey or dark brown (WII-ADA1495). This marking is broken in some individuals (WII-ADA607; Figs 16V, 17B) or may be replaced by a pair of broad concave stripes (WII-ADA1035), or completely absent (WII-ADA603; Figs 16W, 17F). Some individuals have a white bar on forehead covering the anterior part of the upper eyelids (WII-ADA608; Figs 16I, J, 17A); groin and thighs may have irregular dark-brown patches or dark-brown patch with bright irregular sized and shaped yellow spots; pale yellow mid-dorsal line may be present and a similar line on hindlimbs originating from the mid-dorsal line above vent and running dorsally along thighs and tibia and ventro-laterally on tarsus (WII-ADA1499; Fig. 16N, O, U); dark brown spots may be present or absent on flank and limbs; one individual from Ngengpui Wildlife Sanctuary have patches of yellow flecks on head, back, hind limbs and lower arms were pale-yellow on top (WII-ADA1035; Figs 16X, 17G); intensity on the spinules and tubercles on head, back and limbs varies among individuals as dense to scattered.

Raorchestes garo differs from R. annandalii, R. dulongensis, R. hekouensis, R. hillisi, R. huanglianshan, R. jadoh, R. leiktho, R. malipoensis, R. mindat and R. parvulus by larger body size, SVL 19.9–26.9 mm in adult males (vs. SVL in adult males, 17.3–19.6 mm in R. annandalii, 15.0–19.0 mm in R. dulongensis, 16.1–17.5 mm in R. hekouensis, 15.9–17.7 mm in R. hillisi, 17.0–19.6 mm in R. huanglianshan, 13.6–14.0 mm in R. jadoh, 15.7–15.8 mm in R. leiktho,14.6–17.7 mm in R. malipoensis, 16.7–18.3 mm in R. mindat, 17.0–18.6 mm in R. parvulus); it differs from R. annandalii, R. cinerascens nov. comb., R. parvulus, and R. shillongensis by the absence of concave stripes on dorsum (vs. present); it differs from R. andersoni by the presence of spinules on dorsum (vs. scattered tubercles on dorsum) and three dark bands on thigh and tibia (vs. single band on thigh and tibia); it differs from R. kempiae by distinct canthus rostralis (vs. indistinct canthus rostralis), enlarged dark brown patches with or without light patches present on groin and lateral aspect of thigh (vs. a small brown streak present on groin and no dark patches on lateral aspect of thigh), a white bar on inter-upper eyelid space may be present or absent (vs. a distinct or indistinct dark bar may be present or absent), hourglass pattern may be present covering head and dorsum or absent (vs. hourglass pattern absent, only “)(“ mark may be present on dorsum); it differs from R. hillisi, R. huanglianshan and R. menglaensis by its snout length being smaller than or equal to eye length (vs. snout length longer than eye length); differs from R. jakoid by presence of enlarged dark brown patches with or without light patches on groin and lateral aspect of thigh (vs. absent); it differs from R. longchuanensis by inter-upper eyelid width smaller than eye length (vs. inter-upper eyelid width greater than eye length); it differs from R. malipoensis by inter-upper eyelid width smaller than eye length (vs. inter-upper eyelid width greater than eye length); it differs from R. menglaensis by its snout length being smaller than or equal to eye length (vs. snout length longer than eye length); it from R. rezakhani by presence of spinules on dorsum (vs. scattered tubercles on dorsum), concave stripes on dorsum absent (vs. present), enlarged brown patches without or with yellow spots on groin present (vs. short brown streak on groin); it differs from R. tytthus nov. comb. by its snout length being smaller than or equal to eye length (vs. snout length greater than eye length), inter-upper eyelid width smaller than eye length (vs. inter-upper eyelid width greater than eye length), inter-upper eyelid width smaller than or equal to snout length (vs. inter-upper eyelid width greater than snout length); it differs from R. yadongensis by snout length being greater than or equal to inter-upper eyelid width (vs. inter-upper eyelid width greater than eye length), inter-upper eyelid width smaller than eye length (vs. inter-upper eyelid width greater than eye length). Detailed morphological comparison with other congeners included in this study is given in Table 1.

The calls of R. garo were recorded at Tura Peak, Meghalaya on 27 May 2022 at an ambient temperature of 28.2°C and at Lakhicherra, Assam on 18 April 2019 at an ambient temperature of 28.8°C between 18:30 hrs and 19:30 hrs. The call description is based on 42 calls from two individuals (WII-ADA1495 and WII-ADA601). The calls are single type, non-pulsatile (Fig. 18), initially emitted as a single call without a group, and gradually emitted in groups (4.72 ± 2.22 calls per call group; 2–13 calls/call group). The mean call duration is 28.57 ± 2.74 ms (20–32 ms) with a call rise time of 1 ms and call fall time of 27.55 ± 2.71 ms (19–31 ms). The interval between calls is 154.31 ± 7.02 ms (144–170 ms) when emitted in groups. The mean dominant frequency of the call is 2860.84 ± 49.55 Hz (2799.3–2971.6 Hz). A detailed comparison of the advertisement calls with those of other congeners is presented in Table 2.

Raorchestes garo is sister to R. leiktho (UFB 99 and PP 1; Figs 2, 3). The genetic divergence of R. garo with other congeners included in this study are 4.2–9.2% in the 16S, 13.7–21.2% in the cyt b and 9.5–16.4% in the COI gene (Table S7A–C).

This species is distributed in northeast India from western part of Meghalaya to the eastern part of Arunachal Pradesh in the Namdapha Tiger Reserve. This species is also distributed in the Barail Hills of Assam and Nagaland, in Manipur, and in Mizoram. It is mostly associated with lowland evergreen forests (Fig. 19A). This species was so far known from 50–1480 m a.s.l. across hills on the southern slopes of Brahmaputra Valley, India. Al-Razi et al. (2020a) reported this species as R. longchuanensis from Satchari National Park in Bangladesh. Wu et al. (2019) reported this species as R. cangyuanensis from Cangyuan, China. Lalronunga et al. (2021) reported from Mizoram as R. cangyuanensis. Choudhury et al. (2001) reported this species from Garbhanga Reserve Forest and Kulsi Reserve Forest in Assam, and Ao et al. (2003) reported it from Dzulake, Nagaland which needs further examination to confirm the records.

Calling males were recorded during April–June from perches 1–2 metres above the ground and from roadside forest areas dominated by bamboo thickets (Fig. 20A, B). We also recorded the species calling from the leaves of a small tree about five metres above the ground and from a bamboo thicket at a height of six metres above the ground in Charoikhullen, Manipur. We observed a single female individual of this species on roadside vegetation in Teirei, Dampa Tiger Reserve, Mizoram in September 2021.

Naveen et al. (2024) reported rediscovery of “R. garo” based on five specimens (SACON VA 809, 163, 305, 306, 308) collected from an unnamed locality with geographical coordinate given as “25.51°N, 90.38°E, 895 m” in Garo Hills, Meghalaya and one specimen (SACON VA 129) from Daribokgre Community Reserve (25.47297°N, 90.3148°E, 1200 m), that they claimed as a “topotype”. However, the 16S gene sequence data in Naveen et al. (2024) comes from a specimen (SACON VA 809) collected approximately 15 km east of Tura. Morphological description of the alleged “topotype” (SACON VA 809) do not match the original description in terms of dorsal colour pattern. The original description of R. garo mentions an hourglass pattern on dorsum, but this was absent in SACON VA 809. Although Naveen et al. (2024) mentioned that two of the specimens such as VA 305 and VA 308 have hourglass patterns, they did not generate molecular data for these two specimens. The holotype (ZSIC19187) of R. garo was originally collected by S.W. Kemp from “above Tura” which is the ridge/peak immediately above Tura (see Paiva 1919). We therefore argue that without justification, Naveen et al. (2024) considered SACON VA 809 as a topotype of R. garo, and provided a misleading phylogenetic status of R. garo.

The DNA sequence (16S) of the “R. garo” topotypical specimen (SACON VA 809) submitted by Naveen et al. (2024) did not cluster with our topotypical samples of R. garo (WII-ADA1493, WII-ADA1494, WII-ADA1499) collected from Tura Peak (= above Tura) (25.50302°N; 90.23853°E; elevation 1030 m a.s.l.; Figs 2, 3). The genetic divergence of the true topotypical samples of R. garo and the specimen of “R. garo” of Naveen et al. (2024) is 6.5–7.0% in 16S gene (Table S7A–C). Naveen et al. (2024) stated that R. garo is phylogenetically allied to R. shillongensis. However, our phylogenetic analyses indicate R. shillongensis (topotype; WII-ADA1460) as distinct from R. garo (topotype; WII-ADA1493, WII-ADA1494, WII-ADA1499; Figs 2, 3). Our phylogenetic analyses are strongly supported by acoustic characteristics of the two species (see under respective description and comparison). This suggests that SACON VA 809 reported by Naveen et al. (2024) is a misidentification of R. garo and it represents an undescribed lineage of Raorchestes. Thus, we consider SACON VA 809 as an invalid topotype of R. garo based on accurate type locality and the phylogenetic results of this study.

“Philautus namdaphaensis” was originally described by Sarkar and Sanyal (1985) from Farmbase Camp (at 350 m a.s.l.), Namdapha National Park, Arunachal Pradesh based on three adult males collected by S. Biswas. Later, Sengupta et al. (2000) reported this species from Garbhanga Reserve Forest, Assam, and Mathew and Sen (2009), and Sen et al. (2013) reported it from Nokrek Biosphere Reserve, Meghalaya. On 9 May 2023 we collected two specimens of bush frogs from Haldibari (27.52453°N; 96.39913°E; elevation 500 m a.s.l.), Namdapha Tiger Reserve, Arunachal Pradesh (Fig. 15U) on the north bank of the Noa-Dihing River. These two specimens conform to the original description of “Philautus namdaphaensis” based on the following characters: 1) mid dorsal line from snout to vent, 2) limbs with crossbars and a line originating at vent reaching to heel through dorsal aspect of thigh and tibia, 3) white bar on interorbital space, 4) dark brown blotches on groin and lateral aspects of thighs.

“Raorchestes manipurensis” was described by Mathew and Sen (2009) from Leimatak, Manipur based on a single specimen. So far, this species is only known from the type locality. On 25 July 2022 we collected a topotypical specimen (WII-ADA1645; Fig. 17H) from Leimatak (24.59375°N; 93.66256°E; elevation 480 m a.sl.) that conforms to the original description. This individual matches the original description by the following set of characters: 1) head wider than length, 2) distinct canthus rostralis, 3) vomerine teeth absent, 4) a faint hourglass shaped patch covering head from inter-upper eyelid space and back (dark in holotype), posterior ends of this patch directing towards groin; 5) brown and pale white patches on flank near groin.

Our phylogenetic analyses involving topotypical samples of “P. namdaphaensis” and “R. manipurensis” resulted with them nested with the topotypical samples of R. garo (Figs 2, 3). The topotypical samples of R. garo have genetic divergences of 0.0–0.6% with topotypical samples of “P. namdaphaensis” and 0.4–1.1% with the topotypical sample of “R. manipurensis” in the 16S gene (Table S7A–C). Morphological examinations of the topotypes of the three species (R. garo, “P. namdaphaensis” and “R. manipurensis”) and examinations of the type series of “P. namdaphaensis” did not reveal any strong differentiating characters to separate these three species.

Morphological and molecular studies of the newly collected material from different localities in northeast India suggests R. garo is a polymorphic species (see under redescription section above). We have recorded individuals of R. garo from Tura peak that resemble the typical morphotype of “P. namdaphaensis” (Fig. 16A–H). Mathew and Sen (2008) also reported “P. namdaphaensis” from Nokrek Biosphere Reserve, Meghalaya probably based on this character. The colour and pattern of “R. manipurensis” provided in the original description and the photograph of the holotype by Mathew and Sen (2009) resemble the typical morphotype of R. garo from the type locality. Therefore, these are unreliable and cannot be used as diagnostic characters. Based on molecular data and morphological characters, we propose to treat “Philautus namdaphaensis” and “R. manipurensis” as junior subjective synonyms of R. garo.

“Raorchestes cangyuanensis” was described from Cangyuan, China (Wu et al. 2019). Subsequently, Lalronunga et al. (2021) reported this species from Hmuifang, Mizoram and referred to a previous record of R. longchuanensis from Satchari National Park, Bangladesh (Al-Razi et al. 2020a) as “R. cangyuanensis”. Rahman et al. (2022) reported the species from northeast Bangladesh.

Based on the results of their phylogenetic study, Naveen et al. (2024) suggested “R. cangyuanensis” as a junior subjective synonym of R. kempiae. However, in our current phylogenetic analyses, “R. cangyuanensis” is nested with the topotypical samples of R. garo (Fig. 3) collected in this study (see comments under R. kempiae). The genetic divergence between R. garo collected for this study and “R. cangyuanensis” samples is 0.0–0.9% in the 16S gene (Table S7A–C). Thus, we consider “R. cangyuanensis” as a junior subjective synonym of R. garo and state that the previous records of “R. cangyuanensis” from Mizoram should be considered as R. garo.

Ixalus kempiae Boulenger, 1919: 208.

Rhacophorus (Philautus) kempiae — Ahl (1931): 53, 69.

Philautus kempiae — Bourret (1942): 450–451; Inger (1985): 91; Ahmed et al. 2009: 16.

Philautus (Philautus) kempiae — Bossuyt and Dubois (2001): 41.

Raorchestes asakgrensis Naveen et al., 2024: 362, 365–370.

Raorchestes kempiae — Naveen et al. (2024): 365–367.

Boulenger (1919) described Raorchestes kempiae based on a single specimen collected by A. Kemp from “above Tura”, Garo Hills. The type locality refers to the ridge/peak immediately above Tura (see Paiva 1919). It is possible that this specimen was collected in 1917, which is evident from Paiva (1919) and Brunetti (1918) that A. Kemp was part of their expedition. However, there was no allocated voucher number available for the type in the original description. Chanda (1994) mentioned a possible location of the type specimen as the “British Museum, (Natural History), London, U. K.” which was followed by Bossuyt and Dubois (2001) and repeated in Frost (2025). Chanda et al. (2000) did not provide the presence of the type specimen of “Ixalus kempiae” or “Philautus kempiae” in the collection of the National Zoological Collection of Zoological Survey of India (ZSI), Kolkata (Calcutta). Recently Naveen et al. (2024) provided a photograph of a specimen in ZSI as the “holotype” (ZSI 18859) of R. kempiae. As there was no published literature that mentions the presence of a holotype with the voucher number “ZSI 18859” prior to Naveen et al. (2024), we were unaware of this specimen during our examination of type specimens of Raorchestes/Philautus housed in ZSI. It was lost and found recently in the ZSI collections (https://zsicollections.in/specimen/ZSI0000002582). We later examined this specimen.

On 27 May 2022, we encountered a few individuals of bush frogs (Fig. 21) in Tura Peak (25.502825°N; 90.23921°E; elevation 1060 m a.s.l.), West Garo Hills District of Meghalaya syntopic with R. garo but having a distinctive call pattern. These individuals resemble the original description of Boulenger (1919) by the following morphological characters: 1) dark bar on interorbital space, 2) crossbars on limbs, vertical bars on upper jaw, tubercles on dorsal surface of head and dorsum, 3) barely visible tympanum (although mentioned as “tympanum hidden” in original description), 4) indistinct canthus rostralis, and 5) brown marbling on throat and abdomen. Following exceptions were observed in the newly collected materials: 1) snout shape rounded or sub-oval in dorsal view (rounded in holotype), 2) nostril equidistant between eye and snout tip or closer to snout tip than eye (nostril equidistant between eye and snout tip in holotype), 3) concave stripes on dorsum diffused or not visible. For taxonomic stability, we provided an expanded description and determined the phylogenetic position based on specimens collected from the type locality. Thus, based on morphological similarity with the original description of R. kempiae, we refer to this population from “above Tura” as topotypic material of the species.

Holotype. ZSI18859 (Fide: Naveen et al. (2024)), collected by A. Kemp from “above Tura”.

Topotype: three adult males (WII-ADA1497, WII-ADA1498 and WII-ADA1500) collected by BB, AD and VJ on 27 May 2022 from Tura peak (25.502825°N, 90.23921°E, elevation 1060 m a.s.l.), West Garo Hills District, Meghalaya. Referred materials: two adult males (WII-ADA1951, WII-ADA1952) and one adult female (WII-ADA1953) collected by BB, AD and VD on 1 July 2016 from Nongkhyllem Wildlife Sanctuary (25.90282°N, 91.80384°E, elevation 370 m a.s.l.), Ri-Bhoi District, Meghalaya; one adult male (WII-ADA933) collected by BB and AD on 14 August 2021 from Athibung (25.541758°N, 93.626190°E, elevation 770 m a.s.l.), Peren District, Nagaland; three adult males (WII-ADA1464–WII-ADA1466) collected by BB, AD and VJ on 24 May 2022 from Tura Forest IB campus (25.51596°N, 90.17733°E, elevation 230 m a.s.l.), West Garo Hills District, Meghalaya; three adult males (WII-ADA1476–WII-ADA1478) and one female (WII-ADA1480) collected by BB, AD and VJ on 24 May 2022 from Daribokgre (25.48974°N, 90.32374°E, elevation 1140 m a.s.l.), West Garo Hills District, Meghalaya.

Medium sized Raorchestes, SVL 17.8–22.9 mm in adult males and SVL 23.0–23.3 mm in adult females; head width equal to or greater than length (HL/HW = 0.91–1.01); snout rounded to sub-oval in dorsal view; snout longer than inter-upper eyelid width; canthus rostralis indistinct; numerous tubercles on dorsal surface of head, dorsum, and limbs; numerous spinules on dorsum; pale brown dorsally; pair faint concave brown stripes (“)(”) on dorsum; faint crossbars on limbs; short brown streak present on groin.

Holotype is in bad condition and completely dehydrated (Fig. 21). Lower jaw broken; forelimbs broken at elbow; outer two fingers of the right hand damaged; hindlimbs broken at tibio-tarsal articulation; left foot broken at the base; except first toe, all other toes damaged. Small sized Raorchestes, SVL 16.5 mm; head slightly wider than its length (HL/HW = 0.93); snout rounded in dorsal view and lateral view; snout length equal to eye length; nostril equidistant between eye and snout tip; canthus rostralis indistinct; loreal slightly concave; eyes moderate sized (EL/HL = 0.46); internarial distance smaller than inter-upper eyelid width (IN/IUE = 0.88) and greater than upper eyelid width (UEW/IN = 0.62); tympanum and supratympanic fold invisible; vomerine teeth absent; tongue notch at posterior end; trunk nearly half of snout-vent length (AG/SVL = 0.48); tibia slightly longer than thigh (TL/TBL = 0.93); subarticular tubercles on fingers and toes distinct, rounded; inner metatarsal tubercle present; circum-marginal groove present on finger and toe disc.

Skin on dorsal aspect of head and dorsum shagreened; flat tubercles visible on upper eyelid visible; skin on dorsal aspect of forelimb and hindlimb smooth; skin on throat smooth; belly and ventral side of thigh granular; tibia smooth.

Dorsal aspect of head, dorsum and limbs brown; upper eyelids pale greyish brown; slightly dark broad patch below eye present; pair of slightly dark concave stripes on dorsum barely visible; a broad and very faint cross bar visible on thigh and tibia; throat, belly and ventral aspect of limbs brown, paler than dorsal colour.

Specimen well preserved except for an incision on the ventral aspect of the right thigh. Snout-vent length 22 mm; head as long as wide; snout sub oval in dorsal view, nearly vertical in lateral view, slightly protruding beyond lower jaw in ventral aspect; snout length slightly smaller than eye length (SL/EL = 0.94); snout depressed dorsally at internarial region; narial region pronounced; nostrils oval, laterally positioned and obliquely oriented; nostril closer to snout tip than eye; internarial distance slightly smaller than inter-upper eyelid width (IN/IUE = 0.86) and greater than upper eyelid width (UE/IN = 0.90); canthus rostralis indistinct, oblique; loreal region concave; eye protruding, moderate in size, less than half of eye length (EL/HL = 0.41); interorbital space flat; tympanum barely visible, round, upper part concealed by supratympanic fold; supratympanic fold distinct; vomerine teeth absent, choanae round; tongue posteriorly notched; pair of internal vocal sac opening on lower jaw towards angle of jaw; habitus dorso-ventrally flattened, length less than half of snout-vent length (AG/SVL = 0.46).

Forearm shorter than hand length (FAL/HAL = 0.95); relative length of fingers = I<II<IV<III; each finger with rounded discs; circum-marginal groove present on finger discs; discs on third and fourth finger wider than tympanic diameter; palmar tubercles present; subarticular tubercles distinct, rounded; proximal subarticular tubercles on third and fourth fingers smaller than distal ones; fine granular nuptial pad on first finger; no webbing on fingers.

Hindlimbs slender; thigh length slightly longer than half of snout-vent length (TL/SVL = 0.52); tibia length nearly equal to thigh length (TBL/TL = 0.98); relative length of toes = I<II<III<V<IV; rounded disc on toes; discs slightly smaller than that of fingers; circum-marginal groove present; subarticular tubercles rounded; proximal subarticular tubercle on fourth and fifth toes indistinct compared to that of toe III, IV and V; a distinct inner metatarsal tubercle present, its length smaller than fourth and fifth toe disc widths; outer metatarsal tubercle absent.

Skin on dorsal aspect of snout and head shagreen with irregular sized tubercles; upper eyelids shagreen with indistinct tubercles; prominent tubercles on mandibular region behind the angle of jaw; indistinct tubercles on lateral side of head below loreal region; numerous spinules on dorsum, denser towards dorsolateral side, posteriorly density of spinules decrease and skin nearly smooth in preserved condition; prominent bluntly conical tubercles visible above supratympanic folds in life; indistinct blunt tubercles scattered on middle of dorsum; on dorsal aspect of forelimbs smooth but tubercles visible in life; thighs smooth on top indistinct tubercles on top of the tibia (distinct in life); tubercles on tarsus indistinct; scattered spinules on dorsal part of flank, ventral part of flank smooth; on ventrum, chin smooth; gular skin granular; chest smooth; abdomen coarsely granular; granules on ventral aspect of thighs barely visible unlike in life; tibia and tarsus smooth on ventral aspect; flat granular tubercles sparsely present on ventral aspect of the foot.

Dorsal aspect and lateral side of head, dorsum, and dorsal aspect of limbs brown with slightly darker brown spots; dark brown bar on inter-upper eyelid space; pair of diffused concave dark brown stripes on dorsum, posterior ends of it extended toward groin; broad dark brown crossbar on each tibia and thigh; cross bar barely visible on forearms; on ventral side, head, abdomen and limbs flesh-coloured with brown mottling that is absent on posterior part of abdomen; pale creamy white blotches on granules of abdomen, these blotches decrease posteriorly; similar flecks on ventral aspect of thigh, tibia, and tarsus; disc on fingers and toes yellowish on ventral side, becoming brighter on inner two fingers and inner three toes.

Dorsal aspect of head and dorsum greyish brown; upper eyelids dark grey; grey patch at the middle of posterior part of head; slightly darker streaks present on upper jaw below eyes; dorsal colour on dorsal aspect of forelimbs and hindlimbs slightly paler than that of dorsum except thighs, which is pale yellowish brown; enlarged dark brown patch on vent area; dark brown concave stripes on dorsum visible; dark brown crossbar on dorsal aspect of forearm distinct; similar patches on hand and outer two fingers; crossbar on thigh faint which is distinct on tibia; similar patches on tibia, foot and toes; ventral side of head, trunk, limbs creamy-white with brown mottling; mottling denser along lower jaw, gradually decreasing towards abdomen and completely absent on posterior part of abdomen; brown mottling dense on outer ventrolateral side of forearm, tarsus, and towards knee; mottling absent on inner ventrolateral side of forearm and middle of tibia.

Males have a pair of internal vocal sac openings on the lower jaw, an external subgular vocal sac, and a nuptial pad on the first finger. Supratympanic fold may be distinct or indistinct; concave stripes on dorsum, dark bar on interorbital space, and crossbars on limbs may be diffused or not visible in some individuals; a mid-dorsal line on dorsum starting from snout extending to above vent and a similar line on hind limb radiating from the mid-dorsal line above vent extending to heel present in WII-ADA1478 and WII-ADA933; slightly darker brown streak may be present on groin (WII-ADA933, WII-ADA1478) or this may be continuous with posterior ends of concave stripes on dorsum (WII-ADA1497). According to Boulenger (1919) the tympanum is hidden in the type. However, our newly collected material reveals that the tympanum is barely visible in most individuals but hidden in others (WII-ADA1466, WII-ADA1497, WII-ADA1951 and WII-ADA1952). Details of morphometric variation are given in Table S12.

Raorchestes kempiae differs from R. annandalii in having numerous tubercles and spinules on the dorsum (vs. dorsum smooth); it differs from R. andersoni by presence of a faint short brown streak on groin (vs. enlarge black irregular spot with two yellow spots); it differs from R. cinerascens nov. comb. by its snout being longer than inter-upper eyelid width (vs. snout length equal to inter-upper eyelid width); differs from R. dulongensis, R. hillisi, and R. menglaensis by its head length being less than or equal to width (vs. head longer than width); it differs from R. garo by presence of a faint short brown streak on groin (vs. enlarged dark brown patches with or without yellow or pale white spots present on groin), canthus rostralis indistinct (vs. canthus rostralis distinct); it differs from R. hekouensis by presence of nuptial pad only on first finger (vs. nuptial pad present on first and second fingers); it differs from R. huanglianshan and R. tytthus nov. comb. by its snout length being smaller than or equal to eye length (vs. snout length longer than eye length); it differs from R. jadoh by larger body size in adult males, SVL 17.8–22.9 mm (vs. SVL 13.6–14.0 mm in adult males); it differs from R. jadoh and R. jakoid by its snout length being less than or equal to eye length (vs. snout length greater than eye length), and thigh length being greater than or equal to tibia length (vs. thigh length less than tibia length); it differs from R. leiktho by larger body size adult males, SVL 17.8–22.9 mm (vs. SVL 15.7–15.8 mm); it differs from R. longchuanensis and R. yadongensis by its inter upper eyelid width being smaller than eye length (vs. inter upper eyelid width greater than eye length); differs from R. malipoensis by its snout being longer than inter upper eyelid width (vs. snout length less than or equal to inter-upper eyelid width); it differs from R. menglaensis by its head length being less than or equal to its width (vs. head longer than its width); it differs from R. mindat by presence of short streak on the groin (vs. enlarged black and white patches on groin); it differs from R. parvulus by presence of a faint short brown streak (vs. dark brown marbling enclosing a whitish blotch present on groin); it differs from R. rezakhani by presence of spinules intermixed with tubercle on dorsum (vs. scattered tubercles on dorsum). A detailed morphological comparison with other congeners included in this study is provided in Table 1.

Boulenger (1919) noted that R. garo has truncated snout, whereas R. kempiae has a rounded snout, distinguishing the two species despite the limited descriptions. However, our examination of the holotype of R. garo revealed that its snout is damaged (squeezed; see Fig. 15). Further assessment of newly collected specimens of both species in this study showed that their snouts are actually similar in shape (rounded to sub-ovoid in dorsal view). Therefore, we conclude that snout shape is not a diagnostic character for distinguishing these two species. Similarly, a light-coloured line on mid-dorsum and dorsal aspect of thigh and tibia may be present in some individuals of both R. kempiae and R. garo (Figs 16N, O, U and 22I, L).

The calls of R. kempiae were recorded from three localities: Tura Peak on 27 May 2022 at an ambient temperature of 28.3°C; in the Forest Rest House Campus, Tura on 24 May 2022 at an ambient temperature of 28.0°C and in Daribokgre on 25 May, 2022 at an ambient temperature of 28.0°C. All calls were recorded between 18:30 hrs and 19:30 hrs. the description of the calls is based on analyses of 40 calls from three different individuals (WII-ADA1464, WII-ADA1476 and WII-ADA1497). The calls of R. kempiae are single type, pulsatile and emitted mostly at regular intervals and not in groups (Fig. 18). The mean call duration is 149.29 ± 43.92 ms (67–200 ms) with 3.43 ± 0.59 pulses per call (2–4 pulses per call) and at a pulse rate of 19.21 ± 2.92 pulses/sec (18.52–21.74 pulses/sec). The call rise time is 1 ms and the fall time is 146 ± 46.88 ms (64–199 ms). The pulses are not closely packed; the mean pulse duration is 21.52 ± 8.09 ms (9–37 ms) and the mean pulse period is 54.55 ± 5.06 ms (45–63 ms). The mean inter-call interval is 833.97 ± 298.61 ms (398–1695 ms). The mean dominant frequency is 3306.41 ± 101.26 Hz (3057.7–3488.4 Hz). A detailed comparison of acoustic characters with that of its congeners is given in Table 2.

Raorchestes kempiae is sister to an undescribed lineage from eastern Arunachal Pradesh (UFB 100 and PP 1.0; Figs 2, 3) with genetic divergences of 2.6–3.3% in the 16S, 9.0–10.4% in the cyt b and 5.0–5.8% in the COI genes. The genetic divergences of R. kempiae with other congeners included in this study is 4.4–9.4% in the 16S, 9.0–20.4% in the cyt b and 5.0–16.4% in the COI genes (Table S7A–C).

From our current sampling it appears that R. kempiae has a patchy distribution encompassing Tura peak, Nokrek Biosphere Reserve in Garo Hills and Nongkhyllem Wildlife Sanctuary of Meghalaya State and Athibung in Nagaland State within an elevation range of 230–1140 m a.s.l. (Fig. 19B). Mathew and Sen (2009) reported this species from Sohra, East Khasi Hills, Meghalaya. Naveen et al. (2024) reported this species from Nongkhyllem as “R. asakgrensis”. However, we recover the population from Nongkhyllem Wildlife Sanctuary as R. kempiae sensu stricto (see remark below).

We recorded R. kempiae on shrubs at a perch height of approximately one metre, inside semi-evergreen forest as well as near settlements (Fig. 20A, B). We observed calling individuals of R. kempiae and R. garo in the same habitat type at Tura peak and Daribokgre.

Naveen et al. (2024) provided a phylogenetic status of “R. kempiae” based on a specimen (SACON VA 806) collected from Mikadogre Community Reserve (25.433660°N, 90.398981°E,), South Garo Hills District, Meghalaya at an elevation of 174 m. This collection locality is approximately 18 km southeast of the original type locality of “above Tura” which is located at an elevation of 1000–1200 m a.s.l (see Paiva 1919). We argue that Naveen et al. (2024) overlooked the original description by Boulenger (1919) and did not provide a justification for their treatment of the material from Mikadogre as topotypes of R. kempiae.

In our phylogenetic analyses, the “R. kempiae” of Naveen et al. (2024) did not cluster with the topotypical R. kempiae collected from Tura peak, instead it is nested within the topotypical samples of R. garo (Figs 2, 3) we collected from the same locality. Thus, our robust phylogenetic analyses suggest that the “R. kempiae” of Naveen et al. (2024) should be referred as R. garo. The photograph of an uncollected male with white bar on head provided on page 366 of Naveen et al. (2024) as “R. kempiae” falls within the morphological variation in R. garo across its range (see morphological variation section under R. garo and Figs 16, 17). In the present study, we found that the topotypical morph of R. kempiae corresponds to the original publication of Boulenger (1919) in having a blackish bar on the inter-upper eyelid space which is not found in R. garo (see variation in R. garo, Figs 16, 17). Although the type locality of R. kempiae and R. garo are the same and the two species are found in sympatry, they can be clearly distinguished based on their acoustic characteristics (Fig. 18). Furthermore, in our PCA the type specimens of R. garo and R. kempiae clustered with its respective topotypes collected in this study (Fig. 6E).

Mistaken identity of R. kempiae by Naveen et al. (2024) was subsequently repeated in Naveen et al. (in press) and Warjri et al. (2025). In Naveen et al. (in press) another “topotype” of R. kempiae was reported to be collected near Tura (25.522648°N, 90.185480°E) at an elevation of 210 m a.s.l. Interestingly, Naveen et al. (in press) did not include their previous sequences of “R. kempiae” provided in Naveen et al. (2024) without any explanation. Additionally, Naveen et al. (in press) provided three specimens (RSNFM13–15) under a single GenBank accession number (PV061647) in the phylogenetic figure (“Figure 1”) and “Table 1”. Furthermore, the locations of these specimens in the text and their reference in the phylogenetic tree do not correspond. However, in our phylogenetic analyses all these sequences of the claimed “topotype” of R. kempiae and sequences from Mizoram previously referred as “R. cangyuanensis” were clustered with topotype of R. garo sensu stricto.

Naveen et al. (in press) synonymised R. manipurensis based on specimens (MZMU 2179 and MZMU 2029) collected from Ralruwng (Larong) ca. 50 km southeast of the actual type locality, which they claimed to be the topotype. Similarly, they synonymised “P. namdaphaensis” based on a specimen (V/APRC/A-317) collected from Gibbons Land, Namdapha Tiger Reserve which is located on the southern slope of the Noa-Dihing river. Another specimen (V/APRC/A-563) collected from Magoring village in the Itanagar Wildlife Sanctuary in Arunachal Pradesh on the northern slope of the Brahmaputra River referred to as “near topotype” of “P. namdaphaensis” without any justification or molecular evidence. In contrast, Naveen et al. (in press) used “P. namdaphaensis” sample (ON493540) available in GenBank with the voucher number MZMU-V1277 but did not use either of the two specimens in their phylogenetic analysis.

However, in our study, sequences of “R. manipurensis” and “P. namdaphaensis” of Naveen et al. (in press) and actual topotype of these two species collected in this study were clustered with topotype of R. garo sensu stricto. Thus, we suggest “R. manipurensis” and “P. namdaphaensis” are junior synonym of R. garo and not a synonym of R. kempiae.

Naveen et al. (2024) described a new species, “Raorchestes asakgrensis” from Eman Asakgre Community Reserve (25.36788°N; 90.54344°E; 174 m) of Meghalaya State. In our phylogenetic analyses, the specimen of “R. asakgrensis” (SACON VA 805) is nested with R. kempiae (but not the “R. kempiae” of Naveen et al. (2024)) (Figs 2, 3). The genetic divergence of “R. asakgrensis” and specimens of R. kempiae collected from Tura Peak is 0.7–1.7% in the 16S gene (Table S7A–C). Thus, we consider “R. asakgrensis” as a junior subjective synonym of R. kempiae. We consider this taxonomic chaos created by Naveen et al. (2024) is an artefact of i) sampling gaps involving topotypic material of R. garo and R. kempiae, ii) not assigning materials according to the original morphological description of Boulenger (1919), and iii) providing single DNA sequence data each from the materials collected far away from the original type locality.

An adult male (WII-ADA1309) collected by BB and AD on 10 May 2022 from Deban (27.49662°N, 96.38949°E, elevation 380 m a.s.l.), Namdapha Tiger Reserve, Changlang District, Arunachal Pradesh, India.

Two adult males (WII-ADA3202 and WII-ADA3204) collected by R. N. Venkatesh and S. Dutta on 30 April 2023 from Deban (27.49178°N, 96.39313°E, elevation 580 m a.s.l.), Namdapha Tiger Reserve, Changlang District, Arunachal Pradesh, India.

Five adult males (WII-ADA1339, WII-ADA1341–WII-ADA1344) collected by BB, AD and JV on 13 May 2022 from Motijheel trail (27.48585°N, 96.331475°E, elevation 680 m a.s.l.), Namdapha Tiger Reserve; one adult male (WII-ADA1387) and one adult female (WII-ADA1389) collected by BB, AD and VJ on 20 May 2022 from Motijheel trail (27.48998°N, 96.33484°E, elevation 530 m a.s.l.), Namdapha Tiger Reserve; one adult male (WII-ADA1367) collected by BB, AD and VJ on 14 May 2022 from Kamala Valley (27.4595°N, 96.4279°E, elevation 650 m a.s.l.), Namdapha Tiger Reserve; two adult males (WII-ADA3266 and WII-ADA3267) collected by AD, RNV and SD on 29 May 2023 from Kamala Valley (27.46148°N, 96.42758°E; elevation 650 m a.s.l.), Namdapha Tiger Reserve; two adult males (WII-ADA3243 and WII-ADA3244) and one adult female (WII-ADA3235) collected by AD, RNV and SD on 24 May 2023 from Gandhigram (27.29512°N, 96.90208°E; elevation 1090 m a.s.l.), Changlang District, Arunachal Pradesh; one adult male (WII-ADA3400) collected by RNV on 13 June 2023 from Ranijheel (27.53902°N, 96.4888°E, elevation 910 m a.s.l.), Namdapha Tiger Reserve; two adult males (WII-ADA3422 and WII-ADA3423) collected by AD, RNV and JDG on 17 July 2023 from Kalai (27.72294°N, 96.4346°E, elevation 1110 m a.s.l.), Kamlang Tiger Reserve, Lohit District, Arunachal Pradesh; four adult males (WII-ADA1628–WII-ADA1631) collected by BB on 19 July 2022 from Liyai Khunou (25.49257°N, 94.29186°E, elevation 2150 m a.s.l.), Senapati District, Manipur.

Small sized Raorchestes (Fig. 23), SVL 14.6–20.8 mm in adult males and SVL 19.8–21.9 mm in adult females; snout rounded to oval in dorsal view; snout length slightly less than or equal to eye length (SL/EL = 0.92–1.04); nostrils closer to snout than eye or equidistant between eye and snout tip; inter-upper eyelid width less than or equal to eye length (IUE/EL = 0.73–1.04); internarial distance greater than or equal to upper eyelid width (UEW/IN = 0.65–0.95); internarial distance less than or equal to inter upper eyelid width (IN/IUE = 0.78–1.05); nuptial pad present only on first finger in males; prominent bluntly conical tubercular projections on upper eyelids and posterior part of head; spinules on dorsum; scattered blunt tubercles on dorsum and hindlimbs; “)-(“ dark brown marking on dorsum; three or four dark-brown crossbars on thigh and tibia; short dark stripe present on groin.

Holotype is in good condition except for an incision on the ventral side of the right thigh. Adult male with vocal sac, SVL 20.4 mm; head as long as wide; snout rounded in dorsal view, truncated in lateral view, its length equal to eye length and greater than inter-upper eyelid width (IUE/SL = 0.87); narial region slightly protruding; nostrils oval, obliquely oriented, equidistant between eye and snout tip; loreal region concave; canthus rostralis distinct, rounded and oblique; internarial distance greater than upper eyelid width (UEW/IN = 0.79) and slightly smaller than inter-upper eyelid width (IN/IUE = 0.92); tympanum indistinct, round, one third of the eye length (HTYD/EL = 0.33); supratympanic fold distinct; vomerine teeth absent; choanae round; tongue posteriorly notched; pair of internal slit like openings on lower jaw; trunk more than half of snout-vent length (AG/SVL = 0.55).

Forelimbs slender; forearm shorter than hand (FAL/HAL = 0.91); third finger longest; relative length of fingers = I<II<IV<III; finger width rounded disc; disc on third finger slightly wider than tympanic diameter (HTYD/FID = 0.77); palmar tubercles indistinct; subarticular tubercles distinct, round, proximal subarticular tubercle on finger II and IV small; fine granular nuptial pad present on first finger; webbing on fingers absent.

Hindlimbs slender; thigh length half of snout-vent length (TL/SVL = 0.51); tibia slightly shorter than thigh (TBL/TL = 0.94); fourth toe longest; relative length of toes = I<II<II<V<IV; toe with rounded disc; disc width of fourth toe equal to that of third finger; subarticular tubercles distinct, round, proximal subarticular tubercle on toe IV and V small and indistinct; inner metatarsal tubercle present, its length equal to disc width of first and second toe; outer metatarsal tubercle absent; webbing slight, not reaching second subarticular tubercle on fourth toe.

Skin on dorsal aspect of snout shagreen; inter-upper eyelid space smooth; upper eyelid and loreal region shagreen; bluntly conical tubercles on upper eyelid, posterior part of head not visible in preserved condition unlike in life, pair of enlarged bluntly conical tubercle visible posterior to upper eyelid; one or two tubercles behind angle of jaw; flat granular tubercles present on dorsal surface of tongue; spinules present on dorsum and flank, spinules absent towards vent; forelimb and hindlimb smooth on dorsal aspect, spinules on thigh and tibia not visible unlike in life; head on ventral aspect smooth, gular region indistinctly granular; chest smooth; abdomen, thighs on ventral aspect granular; tibia on ventral aspect granular; two tubercles below vent.

Dorsal aspect of head, dorsum, limbs pale greyish brown with slightly darker brown flecks; pair of reddish, blunt tubercles posterior to upper eyelid; a reddish tubercle behind angle of jaw; pair of concave indistinct, brown stripes on dorsum; a broad brown crossbar on forearm; two brown crossbars on thigh and tibia and one on tarsus; diffused brown stripe along supratympanic fold; another similar stripe on upper jaw ventral to eye; irregular white spots along upper jaw; on ventral aspect of head, abdomen, and limbs flesh coloured with brown mottling; pale yellow tinge on gular region; brown patch around vent.

Colour pattern similar to life coloration; dorsally pale greyish brown, head slightly darker, limbs and flank paler; on ventrum, abdomen and limbs pale cream coloured with brown mottling.

Males have a pair of internal vocal sac openings, subgular external vocal sac and nuptial pad on the first finger; head longer than wide in females, but in males head wider than long or width equal to length. Dorsal colour varies from pale greyish brown to pale yellowish brown; concave stripes on dorsum may be broken or faint in some individuals; number of crossbars on thigh and tibia varies between 2–4; axilla and groin may be pale yellow in some individuals; disc on inner two fingers may be pale yellow. Detailed morphometric variation between the individuals of this species is given in Table S12.

Raorchestes orientalis sp. nov. differs from R. andersoni by short stripe present on groin (vs. large black spot with two yellow spots present on groin); it differs from R. annandalii by skin on dorsum with spinules (vs. skin on dorsum smooth); it differs from R. cinerascens nov. comb. by short stripe present on groin (vs. a spot partially encircled by yellow tinge present on groin), dense spinules on dorsum (vs. scattered tubercles on dorsum); it differs from R. dulongensis by presence of nuptial pad on first finger in males (vs. nuptial pad absent); it differs from R. hekouensis by nuptial pad present only on first finger (vs. nuptial pad present on first and second finger); it differs from R. garo by short stripe present on groin (vs. enlarged dark brown patches with or without white or yellow patches present on groin); it differs from R. hillisi, R. huanglianshan, R. menglaensis, and R. tytthus nov. comb. by snout length being less than or equal to eye length (vs. snout longer than eye length); it differs from R. jadoh and R. jakoid by snout length being less than or equal to eye length (vs. snout length greater than eye length), and thigh length being greater than or equal to tibia length (vs. thigh length less than tibia length); it differs from R. kempiae by presence of distinct “)-(“ on dorsum (vs. comparatively faint “)(“mark on dorsum), 2–4 cross bars on tibia and thigh (vs. three bars on tibia and thigh); it differs from R. leiktho by presence of a pair of concave stripes on dorsum (vs. pair of anteriorly connected stripes on dorsum); it differs from R. longchuanensis by inter-upper eyelid width being less than or equal to eye length (vs. inter-upper eyelid width greater than eye length); it differs from R. malipoensis by short stripe present on groin (vs. black patches present on groin); it differs from R. mindat by short stripe present on groin (vs. enlarged black and white patches present on groin); it differs from R. parvulus by short stripe present on the groin (vs. dark brown marbling enclosing a whitish blotch present on groin); it differs from R. rezakhani by presence of dense spinules on dorsum (vs. scattered tubercles on dorsum); it differs from R. shillongensis by short stripe present on groin (vs. dark brown patch with white crown shaped mark present on groin); it differs from R. yadongensis inter-upper eyelid width being less than or equal to eye length (vs. inter-upper eyelid width greater than eye length). Morphological comparisons with other new species described in this study are given in respective sections and Table 1.

The calls of R. orientalis sp. nov. were recorded in Deban, Namdapha Tiger Reserve on 10 May, 2022 and in Kamala Valley, Namdapha Tiger Reserve on 16 May 2022 at 19:25 hrs and 19:30 hrs at ambient temperatures of 25.8°C and 22.7°C respectively. The description of calls is based on 60 calls including those of the two individuals (WII-ADA1309 and WII-ADA1367). The calls are single type, non-pulsatile, emitted as a single call at start, gradually emitting calls in groups (2–6 calls per group) (Fig. 24). The mean call duration is 24.6 ± 2.79 ms (15–28 ms) with a rise time of 1.13 ± 0.39 ms (1–3 ms) and a fall time of 23.43 ± 2.85 ms (13–27 ms). The mean interval between calls is 220.92 ± 23.13 ms (162–295 ms) when calls emitted in groups. The dominant frequency is 3958.52 ± 202.2 Hz (3617.6–4177.4 Hz). A detailed comparison of the advertisement calls with those of the congeners is presented in Table 2.

Raorchestes orientalis sp. nov. is sister to two other new species with strong node support (UFB 100, PP 1) (Figs 2, 3). The genetic divergence with its congeners is 3.2–9.1% in the 16S, 9.3–18.7% in the cyt b and 6.0–14.9% in the COI genes (Table S7A–C).

The specific epithet is derived from the word “oriental” meaning eastern, in reference to its distribution in the easternmost part of India.

Eastern bush frog.

Raorchestes orientalis sp. nov. is currently known from Namdapha Tiger Reserve, Kamlang Tiger Reserve and Gandhigram Village in Arunachal Pradesh, and Liyai Khunou in Manipur (Fig. 25A). Calling males were recorded among understorey of evergreen forest at approximately one metre height above ground (Fig. 20C, D). In Gandhigram this species was recorded among shrubs near small streams in the forests and near human settlements.