Indirana bhadrai

Arpitha, J., Naveen, R. S. & Priti, Hebbar, 2025, Larval descriptions and natural history of two endemic frogs (Amphibia: Anura) from the Western Ghats, India, Zootaxa 5604 (2), pp. 167-175 : 169-170

Indirana bhadrai

External morphology. Specimen numbers: BNHS 6809–6812. External larval morphology is described based on four specimens at Gosner Stages 36–38 ( Table 1 ; Fig. 2A ). Small-sized , semiterrestrial tadpoles (TaL 15.4–16.1mm), body oval, longer than wide ( BL / BW 1.9 ). In the lateral view, body depressed ( BW / BH 1.3 ). Eyes positioned dorsally, directed dorso-laterally. Nares closer to eyes than snout ( NSD / END 1.7 ). Inter-Narial Distance smaller than Inter-Orbital Distance (1.1). Snout declivous in dorsal view. Spiracle sinistral and lacking inner wall. Coiled gut visible from the ventral view. Tail length twice as long as body length (TL/ BL 1.6 ). Tail thin, cylindrical, and tapering muscular structure with rudimentary dorsal and ventral fins beginning at the posterior most quarter of the tail muscle. Vent tube medial and short. Oral disc ( Fig. 2B ) relatively small ( BW / ODW 2.6 ), ventrally situated and not emarginated. Upper labium inverted ‘V’ shaped. Labial tooth row formula ( LTRF) 4(1–4)/4(1–2). Row P 1 shorter than other posterior tooth rows, with a large medial gap. Jaw sheaths strongly compressed transversely, keratinised and well-serrated. Marginal papillae present only on commissures, medium-sized, submarginal papillae absent.

Colouration. In life, the dorsal colouration of the tadpoles varied from dark to pale brown. Brown to golden coloured irregular patches on the body, with two prominent, almost circular patches behind the eyes on the dorsal side. Dark brown to black coloured thin vein-like patterns on the dorsolateral side, behind the eyes. Three to four thin, dark perpendicular stripes over the hind limbs. Tail with thick orange to brown stripes, more prominent near the base than towards the posterior end. Ventral colouration ranged from uniform white to pale orange. Gut coils pale green to greenish-grey in colour. In preservation, the dorsum turns black and the ventral side is creamy white.

Natural history. Adults and tadpoles ( Fig. 2C,D ) were encountered on rocky mountainous slopes containing a thin film (<2 mm) of water streaming over them, in areas locally called Attigundi and Basignamutt ( Fig. 2G ). We observed abundant algal growth on these slopes, and the tadpoles were seen feeding on them. Ambient temperature and relative humidity of the site in Attigundi were measured at 19°C and 98%, respectively. The water flowing over the rock formation had a temperature of 19.9°C, pH 5.12, contained 0.02 ppt of total dissolved solids and a water conductivity of 0.07 mS. Tadpoles were largely found on the open rocks than the regions on the rock with plant growth. Cement structure constructed adjacent to the rocky slopes, resembling the latter in algal abundance and water flow also had tadpoles of I. bhadrai ( Fig. 2E ). Newly hatched tadpoles lacked hind limbs but were seen moving actively across the rock with the help of their proportionately long muscular tail and some of them were found wriggling on the roadsides. The older tadpoles with completely developed hind limbs were also seen crawling actively but leapt and fled when disturbed.

Egg clutches (three) were located within moist crevices along the rocky slopes, mostly hidden from plain sight ( Fig. 2F ). Each clutch comprised approximately 150 to 200 eggs and was not submerged in water. One of the egg clutches had embryos with well-developed external gills. The eggs measured about 4 mm in diameter at Gosner Stage 17 and about 4.9 mm at Gosner Stage 20. Notably, the tadpole tails were observed to be more than twice the length of the body within the eggs, making it easy to identify and distinguish them from other species sharing the same habitat. Post-hatching, the tadpoles congregated in small puddles beneath the oviposition sites.

Figures

FIGURE 2. Indirana bhadrai. (A) dorsal, ventral and lateral views of a preserved tadpole, scale bar = 1 cm; (B) detail of the oral disc; (C) an adult male; (D) tadpole in life; (E) aggregation of tadpoles on cement surface; (F) clutch containing about 200 eggs (Gosner Stage 18) on rocky slopes; (G) rocky habitat of I. bhadrai tadpoles with a thin film of water flowing over it.