Rohanixalus baladika ( Riyanto and Kurniati, 2014 ) Biju & Garg & Gokulakrishnan & Chandrakasan & Thammachoti & Ren & Gopika & Bisht & Hamidy & Shouche, 2020

Biju, S. D., Garg, Sonali, Gokulakrishnan, G., Chandrakasan, Sivaperuman, Thammachoti, Panupong, Ren, Jinlong, Gopika, C., Bisht, Karan, Hamidy, Amir & Shouche, Yogesh, 2020, New insights on the systematics and reproductive behaviour in tree frogs of the genus Feihyla, with description of a new related genus from Asia (Anura, Rhacophoridae), Zootaxa 4878 (1), pp. 1-55 : 37-39

Rohanixalus baladika ( Riyanto and Kurniati, 2014) comb. nov.

Sumatran Bubble-nest Frog

( Figs. 1–2 , 4 , 7 , 14–15 ; Tables 1 , 3 , 4 )

Original name and description. Chiromantis baladika Riyanto and Kurniati, 2014 . Riyanto A. and Kurniati H. 2014. Three new species of Chiromantis Peters 1854 ( Anura : Rhacophoridae ). Russian Journal of Herpetology, 21: 65–73. Type. Holotype, MZB Amph. 17.935, by original designation. Type locality. “ West Sumatra Province (1° 26’ 15.3 S, 101° 31’ 47.7 E; elevation 273 m a.s.l.) at temporary pool in palm oil plantation”, Indonesia. Current status of specific name. Valid name as Rohanixalus baladika ( Riyanto and Kurniati, 2014) comb. nov.

Taxonomic remarks. This taxon was originally described from West Sumatra based on five specimens. We examined the type specimens and find that this species is closely related to members of the genus Rohanixalus rather than Chirixalus due to the following characters: prominent and dense minute speckles throughout the dorsum, lateral surfaces, and dorsal surface of limbs (vs. absent); and a pair of light coloured dorsolateral stripes (prominent to faint, continuous or discontinuous) beginning from the snout tip, extending over the upper eyelid margins, and ending close to the vent on either side (vs. absent) ( Figs. 14 , 15 ). Furthermore, the type series is morphologically very similar to new collections from West Sumatra, the phylogenetic position of which is confirmed in the new genus ( Figs. 1 , 2 ). Hence, based on the new molecular and morphological evidence presented herein, we propose to formally reallocate Chiromantis baladika Riyanto and Kurniati, 2014 (= Chirixalus baladika ) to Rohanixalus baladika ( Riyanto and Kurniati, 2014) comb. nov.

Furthermore, Rohanixalus baladika is morphologically close to R. marginis and R. nauli due to similar adult size, male SVL 21–22 mm (vs. SVL 21 mm in R. nauli and SVL 22.8 mm in R. marginis ), as well as the presence of weak to prominent dorsolateral stripes and faint to prominent scattered dorsal spots in all the three species. Many of the diagnostic characters mentioned in the original publication ( Riyanto & Kurniati 2014) for distinguishing R. baladika from R. marginis are variable within the types series (especially the prominence and thickness of the dorso- lateral stripes) ( Fig. 14 ), except for the absence of rudimentary webbing between fingers III and IV (vs. present in R. marginis , but absent in R. nauli ). While the comparison with R. nauli is based on the absence of dorsolateral stripes and dorsal spots ( Riyanto & Kurniati 2014), our examination of the holotype of R. nauli suggests the presence of faint dorsolateral stripes ( Fig. 15 ). Since the description of R. nauli is based on a single specimen, this character cannot be considered reliable without considering possible variation. In the present study, we also examined new collections from North and West Sumatra and found dorsal colouration as well as the prominence of dorsolateral stripes to be variable among individuals ( Fig. 14 ). These two species, along with R. marginis , are also found in close geographical proximity. Our new collections also show R. baladika and R. nauli to be genetically close with a shallow divergence of 0.2–0.6% ( Fig. 2 ). Hence, R. baladika and R. nauli are likely to be synonyms, pending further validation.

Diagnosis. Small-sized adults (male SVL 21–23 mm) with slender body; snout rounded to subovoid in dorsal view; the entire dorsum, lateral surfaces, and dorsal surface of limbs covered with fine dark brown speckles, some speckles clumping together to form dark irregular blotches or reticulation on the dorsum; a pair of narrow, prominent to faint, continuous or discontinuous, dorsolateral stripes starting from the snout tip, extending over the eyes, and ending close to the vent; the prominence of dorsolateral stripes and scattered dorsal spots highly variable among individuals (e.g, dorsolateral stripes faint in Paratype MZB Amph. 17.938 and MZB Amph. 16661, Fig. 14 ); lateral surfaces of the head, including tympanic region, darker than dorsal colouration; foot webbing moderate, up to the second subarticular tubercle on either side of toe IV; eggs light green in colour and laid in bubble nests .

Genetic divergence. For the mitochondrial 16S gene, Rohanixalus baladika differs from other genetically known congeners ( Fig. 1 ) by: 8.3–11.3% from R. hansenae ; 8.7–9.6% from R. senapatiensis ; 9.4–10.1% from R. shyamrupus ; and 9.9–11.8% from R. vittatus . For detailed intra-generic comparison see Table 3 . Further, our new collections from North Sumatra and West Sumatra are divergent by 0.2–0.6%.

Distribution. Rohanixalus baladika is currently known only from West Sumatra and North Sumatra Province in Indonesia.

Figures

FIGURE 1. Maximum Likelihood tree showing phylogenetic relationships among 124 representative taxa from all recognised genera of the subfamily Rhacophorinae. Relationships are inferred based on 1,937 bp of mitochondrial (12SrRNA, tRNAVAL, 16SrRNA) and nuclear (RHO and RAG1) genes. Numbers above and below the branches indicate Bayesian Posterior Probabilities and RAxML bootstrap support values, respectively.

FIGURE 2. A–B. DNA Barcoding based on mitochondrial 16S rRNA sequences: A. genus Feihyla; B. genus Rohanixalus gen. nov.; C. distribution of the new genus Rohanixalus. Images represent the corresponding species and their broad geographical ranges.

FIGURE 4. Distribution of genetically confirmed records of all known Feihyla and Rohanixalus members (indicated by circles) and their respective type localities (indicated by triangles). Numbers corresponding to each species are indicated alongside the distribution spots.

FIGURE 7. Members of the genus Rohanixalus. A. Dorsolateral view of R. hansenae from the type locality, Nong Khor, Thailand; B. dorsolateral view of R. marginis (holotype) from Perlis State Park chalets, Perlis, Peninsular Malaysia; C. dorsal view of R. cf. nauli, from Batang Gadis National Park, North Sumatra, Indonesia with a jelly-nest; D. dorsolateral view of R. cf. nauli, from Batang Gadis National Park, North Sumatra, Indonesia; E. dorsolateral view of R. cf. nauli, from Bukit Barisan Forest Park, North Sumatra, Indonesia; F. dorsolateral view of R. punctatus (Paratype, JBS 9274) from Gwa, Rakhine State, Myanmar (CC Public domain 3.0; AmphibiaWeb); G. dorsolateral view of R. vittatus from Rangat, Middle Andaman Islands, India; H. dorsolateral view of R. senapatiensis from Manipur, India; I. dorsolateral view of R. shyamrupus from Namdapha, Arunachal Pradesh.

FIGURE 14. Variations in dorsal markings and dorsolateral lines in Rohanixalus baladika. A. MZB Amph. 17.938 (paratype); B. MZB Amph. 17.939 (paratype); C. MZB Amph. 17.936 (paratype); D. MZB Amph. 18684; E. MZB Amph. 15409; F. MZB Amph. 16661; G. MZB Amph. 15655.

FIGURE 15. Holotypes of Rohanixalus baladika and R. nauli. A–J. Rohanixalus baladika, MZB Amph. 17.935: A. dorsal view; B. ventral view; C. lateral view of head; D. ventral view of hand; E. ventral view of foot; F. schematic illustration of webbing on foot; G–L. Rohanixalus nauli, MZB.Amph. 14316: G. dorsal view; H. ventral view; I. lateral view of head; J. ventral view of hand; K. ventral view of foot; L. schematic illustration of webbing on foot.