Raorchestes garo ( Boulenger, 1919 )

Boruah, Bitupan, Deepak, V. & Das, Abhijit, 2025, Revision of bush frogs, Raorchestes and Philautus (Amphibia: Anura: Rhacophoridae) from the northeast Indian biodiversity hotspot with description of thirteen new species, Vertebrate Zoology 75, pp. 517-625 : 517-625

Raorchestes garo ( Boulenger, 1919)

Figures 15 , 16 , 17; Tables 1, 2, S 6, S 7, S 12

Synonymy and chresonymy.

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.

Comments on taxonomic status.

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. 16 A – 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.

Material examined.

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

Newly collected material.

Topotypes: five adult males ( WII-ADA 1493 –1496, WII-ADA 1499 ) 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-ADA 1479 ) 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-ADA 858 , WII-ADA 859 ) 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-ADA 861 ) 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-ADA 601 – WII-ADA 605 , WII-ADA 607 , WII-ADA 608 ) 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-ADA 609 , WII-ADA 610 ) 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-ADA 1035 and WII-ADA 1036 ) 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-ADA 1142 ) 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-ADA 1645 ) 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-ADA 1648 and WII-ADA 1649 ) 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-ADA 3211 , WII-ADA 3213 , WII-ADA 3217 , and WII-ADA 3219 ) 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 .

Diagnosis.

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.

Redescription of holotype ( ZSIC 19187 ; Fig. 15 A – D).

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.

Colouration of holotype ( ZSIC 19187 ) in preservative.

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.

Expanded description based on the newly collected topotype ( WII-ADA 1495 : Fig. 16 A – H).

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.

Colouration in life.

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.

Colouration in preservative.

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.

Sexual dimorphism and morphological variation.

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 S 12. 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-ADA 1495 ). This marking is broken in some individuals ( WII-ADA 607 ; Figs 16 V , 17 B ) or may be replaced by a pair of broad concave stripes ( WII-ADA 1035 ), or completely absent ( WII-ADA 603 ; Figs 16 W , 17 F ). Some individuals have a white bar on forehead covering the anterior part of the upper eyelids ( WII-ADA 608 ; Figs 16 I, J , 17 A ); 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-ADA 1499 ; Fig. 16 N, 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-ADA 1035 ; Figs 16 X , 17 G ); intensity on the spinules and tubercles on head, back and limbs varies among individuals as dense to scattered.

Morphological comparison.

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.

Acoustics.

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-ADA 1495 and WII-ADA 601 ). 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.

Phylogenetic relationship and genetic divergence.

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 16 S, 13.7–21.2 % in the cyt b and 9.5–16.4 % in the COI gene (Table S 7 A – C).

Distribution and natural history.

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. 19 A ). 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. (2020 a) 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. 20 A, 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.

Remarks.

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 16 S 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 ( ZSIC 19187 ) 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 ( 16 S) 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-ADA 1493 , WII-ADA 1494 , WII-ADA 1499 ) 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 16 S gene (Table S 7 A – C). Naveen et al. (2024) stated that R. garo is phylogenetically allied to R. shillongensis . However, our phylogenetic analyses indicate R. shillongensis ( topotype; WII-ADA 1460 ) as distinct from R. garo ( topotype; WII-ADA 1493 , WII-ADA 1494 , WII-ADA 1499 ; 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. 15 U ) 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-ADA 1645 ; Fig. 17 H ) 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 16 S gene (Table S 7 A – 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. 16 A – 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. 2020 a) 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 16 S gene (Table S 7 A – 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 .

Figures

Figure 2. A, B Maximum likelihood tree inferred from the concatenated data set (16 S, cyt b, COI and RHO) for Raorchestes species from northeast India, Indo-Burma and Indo-China. Outgroups are not shown in this tree. Numbers at the internal branches represent ultrafast bootstrap values (UFB). Values below 50 are not shown. Scale bar: substitutions per site.

Figure 3. A, B Bayesian tree inferred from the concatenated data set (16 S, cyt b, COI and RHO) for Raorchestes species from northeast India, Indo-Burma and Indochina. Outgroups are not shown in the tree. Numbers at the nodes represent posterior probability (PP) value. Values <0.5 are not shown. Scale bar: substitutions per site.

Figure 15. Raorchestes garo. A – D Holotype of Raorchestes garo (ZSI 19187), A dorsal view, B ventral view, C, D lateral view of head; E – N “ Philautus namdaphaensis ”, E – G holotype (ZSIA 7177); H – J paratype (ZSIA 7179); K – N paratype (ZSIA 7178), N granular belly skin. Scale bar = 10 mm.

Figure 16. Raorchestes garo. A – H WII-ADA 1495 from the type locality, Tura Peak. A Dorsal view (hourglass shaped dark patch on dorsum is shown with a black arrow), B ventral view, C lateral view of head in preserved condition, D dorsal view, E dorsolateral view, F ventral view, G groin, H thighs. I – M WII-ADA 608 from Lakhicherra, Assam. I Dorsal view in preserved condition (Inset image showing spinules on dorsum), J dorsolateral view, K ventral view, L groin, M. thigh; N – Q WII-ADA 1499 from the type locality, N dorsolateral view, O dorsal view, P groin, Q thigh. R – T WII-ADA 1142 from Terei, Mizoram. R Dorsolateral view, S groin, T thigh; U WII-ADA 3217 from Haldibari, Arunachal Pradesh; V, W WII-ADA 607 and WII-ADA 603 respectively from Lakhicherra, Assam; X. WII-ADA 1035 from Ngengpui, Mizoram. Scale bar = 10 mm.

Figure 17. Different morphs of Raorchestes garo in their natural habitat. A – F Barail hills, Assam; G Ngengpui Wildlife Sanctuary, Mizoram; H Leimatak, Manipur (topotype of R. “ manipurensis ” WII-ADA 1645).

Figure 18. Advertisement calls of R. garo (WII-ADA 1495) on left and R. kempiae (WII-ADA 1497) on right. From top to bottom, A, B oscillograms, C spectrogram, D power spectrum. The call marked with an arrow on top in A is expanded in B.

Figure 19. Distribution of Raorchestes species in northeast India. A Raorchestes garo and three others closely related new species; B Raorchestes kempiae, R. shillongensis, R. mindat and three new species. Type localities are denoted with stars.

Figure 20. Habitat at the type localities of Raorchestes species of northeast India. A Forest trail at Tura Peak, the type locality of R. garo and R. kempiae; B forest cover and adjacent lowlands of Garo Hills, from Daribokgre; C a landscape view of forest covers and D a forest trail at Namdapha TR, type localities of R. orientalis sp. nov. and R. nasuta sp. nov.; E hills at Mawsynram, near the type locality of R. mawsynramensis sp. nov.; F Nohkalikai Waterfall and forest cover at the type locality of R. boulengeri sp. nov. in Cherrapunji; G dry stream bed and vegetation in Maruwacherra, near Barail WLS, the type locality of R. barakensis sp. nov. and H forest around Jaintia Hills in Narpuh WLS, at the type locality of R. narpuhensis sp. nov.