Raorchestes khonoma, Boruah & Deepak & Das, 2025

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 khonoma sp. nov.

Figure 38; Tables 1, 2, S 12

Holotype.

An adult male ( WII-ADA 897 ) collected by BB and AD on 8 August 2021 from 2.7 km west of Khonoma village ( 25.64145°N, 93.99801°E, elevation 2040 m a. s. l.), Kohima District, Nagaland, India .

Paratypes.

Three adult males ( WII-ADA 894 –896) collected from the same locality as holotype .

Diagnosis.

Small sized Raorchestes, SVL 16.9–22.0 mm in adult males; head width equal to or slightly wider than length ( HL / HW = 0.94–1.0); snout rounded, its length equal to or slightly less than eye length ( SL / EL = 0.93–1.0); snout length less than or equal to inter-upper eyelid width (0.94–1.04); nostril equidistant to snout tip and eye; inter-upper eyelid width equal to eye length; internarial distance greater than upper eyelid width ( UEW / IN = 0.75–0.91); dorsal colour pale yellowish brown with golden tinge; slightly darker brown and white patches on groin and inner lateral aspect of thigh; single broad, brown crossbar on thigh and tibia.

Description of the holotype.

Adult male with vocal sac, SVL 22 mm; head length equals to width; snout rounded in both dorsal and lateral views, its length slightly less than eye length ( SL / EL = 0.94) and inter-upper eyelid width ( SL / IUE = 0.94); snout sharply sloped anteriorly from internarial region; loreal region slightly concave; canthus rostralis rounded and oblique; interorbital space flat; nostrils oval and obliquely oriented, equidistant between snout tip and eye; eye moderate in size, protruding ( EL / HL = 3.4); pineal ocellus absent; tympanum indistinct, rounded; supratympanic fold distinct; internarial distance smaller than inter upper eyelid width ( IN / IUE = 0.71) and equal to upper eyelid width; tongue posteriorly broad and bilobed; vomerine teeth absent; choanae rounded; pair of slit like openings on lower jaw; symphysial knob on lower jaw; maxillary teeth present; translucent external subgular vocal sac present.

Habitus slender ( AG / SVL = 0.5), dorsoventrally flattened; forelimbs slender, forearm length nearly equal to hand length ( FAL / HAL = 0.97); third finger longest, relative length of fingers = I <II <IV <III; all digits with rounded discs; largest disc on third and fourth finger, disc width of the finger IV greater than tympanic diameter; circum-marginal groove present on each disc present; palmar tubercles barely visible on left hand; subarticular tubercles large and round, proximal ones on third and fourth finger small and indistinct; subarticular tubercles on finger = 1: 1: 2: 2; on flat granules present on palm, a large fine granular nuptial pad on first fingers.

Hindlimbs slender; thigh slightly longer than tibia ( TBL / TL = 0.93) and half of snout-vent length ( TL / SVL = 0.5); tibia longer than foot length ( FOL / TBL = 0.86); relative length of toes = I <II <V <III <IV; toe with rounded disc, as wide as on fingers; circum-marginal groove present on each toe; inner metatarsal tubercle present, outer one absent; subarticular tubercles distinct, round, proximal subarticular tubercles on outer three toes smaller; subarticular tubercles on toes = 1: 1: 2: 3: 2; webbing slight, not reaching the second subarticular tubercle of fourth finger.

Skin on dorsal aspect of head smooth to shagreen on dorsum; few small tubercles scattered on upper eyelid; few tubercles above supratympanic fold; tubercles dorsolateral aspect of dorsum and on tibia sparsely present; tubercles posterior to angle jaw barely visible; forelimb smooth; gular region, chest granular but not as distinct on abdomen; abdomen granular; flank towards ventrolateral aspect granular; ventral aspect of thigh granular but of tibia smooth.

Colouration in life.

Dorsally head, back and limbs pale-yellowish brown with golden tinge; a very faint bar on inter-upper eyelid space; faint crossbars on thigh and tibia; ventrally, anterior part of head pale greyish brown, posteriorly pale yellowish brown with dense white mottling on and sparse brown mottling; abdomen whitish with brown mottling, few black irregular spots on anterior part of the abdomen; forelimb ventrally pale yellowish with brown mottling and brown spots on forearms; thighs ventrally pale yellow brown with brown mottling and irregular white spots; large creamy white patches on tibia; large brown patch on groin and slightly smaller white patch on either side of it; another white patch on inner lateral aspect of thigh towards base.

Colouration in preservative.

Dorsally head and back grey, upper eyelid slightly darker, an indistinct slightly dark bar between upper eyelids; loreal region darker, two indistinct dark streaks on upper jaw radiating from the eye; forelimbs and hindlimbs dorsally greyish brown, slightly darker brown cross bar on forearm, thigh, tibia and tarsus; flank pale greyish brown; on ventral aspect, head cream coloured with brown mottling, dense on anterior part of lower jaw; abdomen cream coloured with small indistinct white spots and brown mottling, irregular small brown patches on abdomen and towards flank; forelimb ventrally with denser brown mottling; hindlimb cream coloured with dense brown mottling, brown crossbars on thigh and tibia visible, pale-white spots on thigh and tibia; no marking on outer lateral aspect of thigh and around vent.

Morphological variation.

Detailed morphological variations are provided in Table S 12. In addition, black spots on the abdomen are absent in the paratypes; a pair of indistinct concave and slightly dark stripes on the dorsum visible on WII-ADA 896 in preserved condition.

Morphological comparison.

Raorchestes khonoma sp. nov. differs from R. andersoni and R. rezakhani by inter-upper eyelid width being equal to eye length (vs. inter-upper eyelid width smaller than eye length); it differs from R. annandalii by snout length being equal to or less than inter-upper eyelid width (vs. snout length greater than inter-upper eyelid width); it differs from R. barakensis sp. nov. by absence of bony projection on humerus (vs. bony projection on humerus present), inter-upper eyelid width being equal to eye length (vs. inter-upper eyelid width smaller than eye length); it differs from R. boulengeri sp. nov. by inter-upper eyelid width being equal to eye length (vs. inter-upper eyelid width smaller than eye length), by absence of spinules on dorsum, few blunt scattered tubercles present (vs. dense spinules on dorsum), and by absence of concave stripes on dorsum, may be barely visible in preserved condition (vs. distinct pair of dark brown concave stripes present on dorsum); it differs from R. cinerascens nov. comb. by presence of a single broad brown crossbar on thigh and tibia (vs. three crossbars on thigh and tibia); it differs from R. dibangensis sp. nov. and R. narpuhensis sp. nov. by inter-upper eyelid width being equal to eye length (vs. inter-upper eyelid width less than eye length), by nostril being equidistant between eye and snout tip (vs. nostril closer to snout tip than eye); it differs from R. dulongensis by head length being equal to or less than head width (vs. head longer than wide), by nostril being equidistant between eye and snout tip (vs. nostril closer to tip of snout); it differs from R. garo by absence of spinules on dorsum (vs. spinules present on dorsum); it differs from R. hekouensis by presence of nuptial pad only on first finger (vs. nuptial pad present on first and second fingers), presence of few scattered tubercles on dorsum (vs. numerous tubercles on dorsum); it differs from R. hillisi and R. menglaensis by head length being less than or equal to head width (vs. head longer than wide), snout length being equal to or less than eye length (vs. snout length greater than eye length); it differs from R. huanglianshan by snout length being equal to or less than eye length (vs. snout length longer than eye length), nostril being equidistant between eye and snout tip (vs. nostril closer to snout tip than eye); it differs from R. jadoh by larger body size in adult males, SVL 16.9–22.0 mm (vs. SVL 13.6–14.0), and inter-upper eyelid width being equal to eye length (vs. inter-upper eyelid width greater than eye length); it differs from R. jakoid by snout length being less than or equal to eye length (vs. snout length greater than eye length), nostril being equidistant between snout tip and eye (vs. nostril closer to snout tip than eye); it differs from R. kempiae by inter-upper eyelid width being equal to eye length (vs. inter-upper eyelid width smaller than eye length), by snout length being smaller than or equal to inter-upper eyelid width (vs. snout length greater than inter-upper eyelid width); it differs from R. lawngtlaiensis sp. nov. by inter-upper eyelid width being equal to eye length (vs. inter-upper eyelid width less than eye length), internarial distance being greater than upper eyelid width (vs. internarial distance equal to upper eyelid width); it differs from R. leiktho by larger body size in adult males, SVL 16.9–22.0 mm (vs. SVL 15.7–15.8 mm), nostrils being equidistant between eye and snout tip (vs. nostrils closer to snout tip), presence of scattered tubercles on dorsum (vs. numerous spinules on dorsum), brown and white patches present on groin (vs. a short brown bar present on the groin); it differs from R. longchuanensis by inter-upper eyelid width being equal to eye length (vs. inter-upper eyelid width greater than eye length); it differs from R. malipoensis by nostril being equidistant between eye and snout tip (vs. nostril closer to snout tip than eye); differs from R. mawsynramensis sp. nov. by absence of spinules on head and dorsum, few blunt scattered tubercles present (vs. dense spinules on top of head and dorsum), by absence of concave stripes on dorsum, may be barely visible in preserved condition (vs. distinct pair of dark brown concave stripes present on dorsum); it differs from R. mindat by presence of brown and white patches on groin (vs. enlarged black and white patches present on groin), by presence of scattered tubercles on dorsum (vs. dense spinules on dorsum); it differs from R. nasuta sp. nov. by head length being less than or equal to its width (vs. head longer than wide), rounded snout (vs. snout acute), inter-upper eyelid width being greater than or equal to snout length (vs. snout length greater than inter-upper eyelid width), presence of slightly dark brown and white patch on groin and thigh (vs. bright yellow patches on groin and thigh); it differs from R. orientalis sp. nov. by presence a few blunt scattered tubercles on dorsum (vs. spinules on dorsum), a single broad cross bar visible on thigh and tibia (vs. three or four narrow crossbars on thigh and tibia); it differs from R. parvulus by thigh length being greater than tibia length (vs. thigh length less than or equal to tibia length); it differs from R. shillongensis by absence of “) (“ mark on dorsum (vs. a dark brown “) (“ mark present on dorsum); it differs from R. tytthus nov. comb. by snout length being equal to or less than eye length (vs. snout length longer than eye length); it differs from R. yadongensis by inter-upper eyelid width being equal to eye length (vs. inter-upper eyelid width greater than eye length), by position of nostrils equidistant between eye and snout tip (vs. nostrils closer to snout tip than eye). Morphologically R. khonoma sp. nov. close to R. monolithus sp. nov. Detailed morphological comparison with other congeneric species is provided in Table 1.

Phylogenetic relationship and genetic divergence.

Raorchestes khonoma sp. nov. is sister to the clade which includes R. dulongensis , R. hillisi and R. yadongensis with weak support ( UFB 71, PP <50; Figs 2 , 3 ). The genetic divergence of R. khonoma sp. nov. with the congeners included in this study are 3.1–6.7 % in the 16 S, 11.2–17.0 % in the cyt b and 7.8–14.3 % in the COI genes (Table S 7 A – C).

Etymology.

The specific epithet is a toponym derived from the name of the village “Khonoma” in Nagaland State where the type series was collected.

Suggested common name.

Khonoma bush frog.

Distribution and natural history.

Raorchestes khonoma sp. nov. is currently known from its type locality Khonoma and Dzuleke village in the Kohima District of Nagaland from an elevation of 2000–2040 m a. s. l. (Fig. 19 B ). This species has also been recorded from low elevation areas at Khonoma Nature Conservation and Tragopan Sanctuary ( KNCTS). Individuals of the species were most commonly found along the subtropical forest margins and hilly terrace croplands (Fig. 33 E ). Gravid females were photographed in June and calling males were recorded from May to September. We observed males calling on shrubs at a perch height of approximatelyone meter above ground level. Many individuals were observed calling from Eupatorium thickets. The area at the type locality was mostly covered by jhum and terrace cultivation.

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 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 33. Habitat at the type localities of Raorchestes species in northeast India. A Lowland forest stream at the type locality of R. lawngtlaiensis sp. nov. in Ngengpui WLS; B landscape view of Mehao WLS from Abango, type locality of R. dibangensis sp. nov. in Abango; C. hill stream and riparian habitat at the type locality of R. shillongensis in Malki, Shillong; D landscape view of the hills at Pumdunlong, the type locality of R. monolithus sp. nov. at Willong Khullen Village; E landscape view of hills and lowland areas at Khonoma, the type locality of R. khonoma sp. nov.; F forest cover at Bompu, Eaglenest WLS at the type locality of R. eaglenestensis sp. nov.; G hill stream and forest cover at Abor hills, habitat of R. magnus sp. nov.; H landscape view of Abor hills and adjacent lowland areas, habitat of R. arunachalensis sp. nov.

Figure 38. Raorchestes khonoma sp. nov. A – C and F, G holotype (WII-ADA 897) in preserved condition. A Dorsal view, B ventral view, C lateral view of head, F ventral view of left hand, G ventral view of left feet. D Dorsal and E ventral view of paratype (WII-ADA 896) in preserved condition. H – L Holotype in life, H dorsolateral view, I ventral view, J groin, K posterior view of thigh, L granules on abdomen. Scale bar = 10 mm.