Raorchestes rezakhani Al-Razi, Maria & Muzaffar, 2020

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 rezakhani Al-Razi, Maria & Muzaffar, 2020

Figure 29; Tables 1, 2, S 12

Material examined.

An adult male ( WII-ADA 1092 ) collected by BB, AD and NGP on 15 September 2021 from Teirei ( 23.694°N, 92.45147°E, elevation 270 m a. s. l.), Dampa Tiger Reserve, Mamit District, Mizoram, India .

Comments on taxonomic status.

The specimen collected during this study conforms to the original type description with the following exceptions. In the original description of the species, Al-Razi et al (2020 b) mentioned nuptial pad absent (vs. in WII-ADA 1092 , small and fine granular nuptial pad present on base of first finger); inner metatarsal tubercle absent (vs. in WII-ADA 1092 , inner metatarsal tubercle present); a bony projection present on ventral aspect of humerus (not mentioned in original description). Importantly Al-Razi et al. (2020 b) mentioned thigh longer than tibia (“ shank ”) in the holotype description (page number 138); but in the morphological measurement table (table 3; page number 137) this opposite to the holotype description in which thigh shorter than tibia for all their type specimens. In WII-ADA 1092 , thigh length is slightly longer than tibia length ( TBL / TL = 0.97). Morphological description of the collected sample is provided below.

Description.

Small sized Raorchestes, SVL = 21 mm; head slightly wider than long ( HL / HW = 0.95); snout rounded in dorsal view and slightly protruding beyond the lower jaw in ventral view, depressed anteriorly from internarial space; snout length equal to eye length and greater than inter-upper eyelid width ( IUE / SL = 0.8); nostrils oval in shape, laterally positioned and obliquely oriented, equidistant between eye and snout tip; canthus rostralis distinct but not sharp; eye protruding, moderate in size ( EL / HL = 0.41); internarial distance equal to upper eyelid width and slightly less than inter-upper eyelid width ( IN / IUE = 0.92); no vomerine teeth; choanae rounded; tongue notched at posterior end, no papillae on it; tympanum indistinct, its diameter one third of eye length; supratympanic fold weak; habitus dorso-ventrally moderately depressed, its length nearly half of snout-vent length ( AG / SVL = 0.49).

Forelimbs slender; finger with rounded disc; circum-marginal groove present on each disc; disc on third finger wider than tympanic diameter ( HTYD / FID = 0.77); relative length of fingers = I <II <IV <III; subarticular tubercles distinct, round; proximal subarticular tubercle on third and fourth fingers smaller than distal ones; palmar tubercles indistinct; rudimentary webbing between third and fourth finger; small and very finely granular nuptial pad present on base of first finger. A bony projection present on the humerus.

Hindlimbs slender; thigh length half of snout-vent length ( TL / SVL = 0.5) and slightly longer than tibia length ( TBL / TL = 0.97); relative length of toes = I <II <III <V <IV; toe with rounded disc; circum-marginal groove present on each disc; subarticular tubercles round; inner metatarsal tubercle present and outer one absent; webbing slight, reaching second subarticular tubercle on fourth finger.

Skin on dorsal aspect of head smooth; distinct tubercles on upper eyelid; few small tubercles behind angle of jaw; small tubercles scattered on dorsum, prominent towards flank; dorsal surface of forelimb smooth; hindlimb smooth on dorsal surface, scattered tubercles on tibia; ventral aspect of lower jaw smooth; chest, abdomen, ventral aspect of base of forelimb, and thigh distinctly granular.

Colouration in life.

Dorsal surface of head, dorsum and limbs pale brown; lateral aspect of head slightly paler than dorsal aspect; “ T ” shaped dark brown marking on inter-upper eyelid space; canthus rostralis including narial region and tympanic region slightly dark brown; irregular size and shape dark brown spots on dorsum; pair of short concave, dark brown patch on anterior part of dorsum; irregular small dark brown spots on flank; moderately broad and short, dark brown stripe on groin, antero-dorsally oriented; one moderately broad dark brown crossbar on forearms, another singular similar patch on each side of crossbar; disc on finger pale yellow with brown mottling; three indistinct, dark brown crossbars on each thigh and tibia; similar patches on tarsus; toe disc pale yellow with brown mottling; on ventrum, head, abdomen and limbs flesh coloured with brown mottling and irregular white flecks; white flecks on anterior part of the abdomen much enlarged and dense.

Morphological comparison.

Morphological comparisons with congeners included in this study are provided in Table 1 and in respective species description section.

Phylogenetic relationship and genetic divergence.

Our newly collected sample ( WII-ADA 1092 ) nested with the R. rezakhani samples from the type locality Lawachara National Park in Bangladesh ( UFB 100 , PP 1.0; Figs 2 , 3 ). The genetic divergence of our sample from Dampa TR with R. rezakhani from Bangladesh is 0.8–1.7 % in the 16 S gene. Raorchestes rezakhani is sister to R. barakensis sp. nov. and R. jakoid . The genetic divergence with its congeners included in this study are 3.4–7.5 % in the 16 S, 12.3–20.4 % in the cyt b genes (Table S 7 A – C).

Distribution and natural history.

This species is known from the type locality Lawachara National Park in Bangladesh ( Al-Razi et al. 2020 b; Hakim et al. 2020). In India, Decemson et al. (2021) reported this species from Pathlawilunglentlang near Dampa Tiger Reserve, Mizoram. Siammawii et al. (2024) recorded this species from Lunglei, Mizoram and reported direct development in this species. Siammawii et al. (2024) reported an egg clutch ( 23 eggs) that was found in a hole of Chinese Albizia ( Albizia chinensis ) about 1.5 m above ground. We recorded the single male on the canopy of a small tree approximately four metres above ground, on a roadside slope at 20: 00 hrs. The canopy of the tree was covered with dense Mikania micrantha and the individual was calling from among it.

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 29. Raorchestes rezakhani (WII-ADA 1092) from Dampa TR, Mizoram, India. A Dorsolateral view, B dorsal view, C ventral view, D dorsolateral view showing groin, E posterior view of thighs in life.