Bioacoustics of Microhyla mihintalei

Genetic comparison. Comparison of the uncorrected pairwise divergences of generated sequences representing four Sri Lankan populations, Dambulla (DZ 1127), Maakandura (DZ 1410, DZ 1418), Mihintale (DZ 1445, DZ 1446) and Anuradhapura (DZ 1468) of Microhyla mihintalei sp. nov . , and one population of Microhyla rubra from Karnataka (SDBDU 2558), along with one available GenBank sequence ( AB 201192 ) show that the genetic divergences range between 2.7−3.2% for the two species (Appendix 2). Acoustic comparison. PCA with unrotated axes on the correlation matrix of the call characters (involving eight variables: Call Duration, Number of Pulses, Pulse Rate, Dominant Frequency, Call Rise Time, Call Fall time, 50% Call Rise Time, 50% Call Fall Time) for the two species shows that Microhyla rubra from India separates out well from M. mihintalei in the PC space ( Fig. 2 ). The separation however is only attributable to the factors that contribute to the PC1 axis, which is explained mostly by Call Duration, Dominant Frequency, Call Rise Time and Pulse Rate (Pulse Rate loads negatively while the other three load positively). The two species overlap completely on PC2 axis ( Fig. 2 ), which is explained mostly by Call Fall time, Number of Pulses and Call Rise Time (Call Rise Time loads negatively and the other two load positively).

Distribution and Natural History. Microhyla mihintalei sp. nov . is found in the lowland dry zone ( Fig. 4 ), mostly in shaded areas, often close to stream and river banks or regions that become fairly stable ephemeral pools during the rainy season. They were observed emerging from borrows in ground to call by around 7.30 PM, slightly after the initiation of calling of M. ornata , a smaller sympatric species. Compared to M. ornata , the abundance of M. mihintalei sp. nov. is much lower, and so are the corresponding numbers of tadpoles in pools. In captivity, M. mihintalei was observed digging rapidly into soil using their hind feet. This indicates that they are active borrowers, and not only ground-burrow utilizers. They lay eggs as loosely arranged sheets on the water surface, mainly in ephemeral pools and their tadpoles also form loose shoals. The tadpole of M. mihintalei was described by Bowatte and Meegaskumbura (2011) , however, as M. rubra from Sri Lanka .

Colour in life ( Fig. 3 ). Dorsum light reddish-brown with a faint light grey band extending from behind the eye to the groin ( Fig. 3D ); lateral side of head and tympanic area dark grey; groin light grey with black patches; two distinct and narrow black streaks extending from the snout along the side of head to near the groin; posterior parts of thigh and tibia light brown with irregular black markings; a narrow black patch extends from anal opening to near the knee; ventral surface grey, throat with dark blackish-brown calling patch ( Fig. 3 ). Variation. See Table 1 for morphometric data from 13 adult males and one female. DZ 1127 (in life): dorsum reddish-brown with brown band extending from behind the eye up to the groin, faint cross-bands on both limbs, lateral side of head and tympanic area light grey ( Fig. 3F ); DZ 1457 (in life: dorsum dark reddish-brown, lateral side of head and tympanic area dark grey; ventral surface light grey with dark grey reticulations especially on the throat; in preservation, light grey dorsum ( Fig. 3G ); DZ 1467 (in life): dark greyish-brown with dark brown dorsal band. Secondary sexual characters. Males: Single vocal sac externally visible on lower jaw. Female (DZ 1418): ova, pigmented on poles (diameter 0.7–1.1 mm , N =15).