Description

Nasikabatrachus bhupathi is a medium-sized frog, with a snout vent lengths of 45.9 and 48.5 mm for the two observed adult male specimens. No female specimens were found. It has an acutely pointed snout with a fleshy protuberance and a hard knob-like projection at the tip and a small, subterminal, and ventral mouth. The mouth is posterior to the snout tip and doesn’t extend beyond a vertical line drawn downwards from the anterior corner of the eye. There is a distinct indent running below the eye to the nostril, with another deeper skin fold extending from below the posterior corner of the eye to behind and below the articulation of the jaw. The nostrils are directed posteroventrally and are located anteriorly, with each nostril positioned below the dorsal margin of the eye and being found nearer to the tip of the snout than the eye. The diameter of the eyes is much smaller than the distance between the anterior edge of the eye and the nostril. The pupils are rounded. The interorbital distance is over three times the width of the upper eyelid. The tympanum on N. bhupathi is not visible externally and they do not have vomerine teeth, or mandibular teeth and odontoids. The long, fluted and elongated tongue is basally attached, has a rounded tip, and is lacking a medial lingual process. It has smooth abdominal skin, limbs, and dorsum and its head is not externally distinct from its globular body. The species also lacks torso-lateral or transverse skin folds (Janani et al. 2017). Nasikabatrachus bhupathi has short and muscular forelimbs that have a restricted range of movement. The fingers are unwebbed with rounded tips and without subarticular, subdigital or supernumerary tubercles. The palm is fleshy and the palmar tubercles are pale white. The relative length of the fingers are 3 > 2 > 1 = 4. The toes have rounded tips and rudimentary webbing between toes, with the outer two metatarsals forming part of the fleshy tubercle. It is separated distally with an outer metatarsal tubercle and a large, hypertrophied shovel-shaped inner metatarsal tubercle with a pale white callused margin. The toes are without digital scutes, tarsal folds, nuptial pads, gular glands, and femoral glands. The macroglands are not evident and there is a short flange on the outer surface of the foot. Relative toe lengths were not reported in the original description. The cloacal opening is directed postero-ventrally (Janani et al. 2017).

The tadpoles of N. bhupathi have large ventral suctorial oral disks along with funnel-shaped vent tubes that open medially. The oral disc is narrow in width and disappears along with the tail as metamorphosis reaches completion. The labial tooth row formula (LTRF) is 2/3(1) (Janani et al. 2017).

Nasikabatrachus bhupathi is differentiated from its only currently known congener, N. sahyadrensis by various osteological, morphological, and behavioral differences. Osteologically, the dorsal crest of the urostyle extends to approximately half of the urostyle length and is sharply tapered posteriorly in N. sahyadrensis while the dorsal crest of the urostyle of N. bhupathi is longer, more strongly developed, and has gentler posterior tapering. Furthermore, the transverse processes of presacral vertebrate are short and acutely anterolaterally orientated in N. sahyadrensis compared to the longer and slightly anterolaterally orientated transverse processes in N. bhupathi. Also the transverse processes on the fourth presacral vertebrate are equal in length in N. sahyadrensis and the fused first presacral vertebrate are broad and bear a well-developed, near-isosceles triangle-shaped accessory while in N. bhupathi, the transverse processes on the fourth presacral vertebrate are slightly shorter than the third presacral vertebrate and first fused vertebrate is narrower and the accessory process is more weakly developed. There is also a distinct accessory process on the third presacral vertebrate in N. sahyadrensis, which is absent in N. bhupathi. The neural spines on the fourth to eighth presacral vertebrates in N. sahyadrensis are less developed and flatter than those of N. bhupathi, which also extend into a semi-cylindrical posterior projecting spine on the anterior half of each vertebra (Janani et al. 2017).

In terms of external morphology, N. bhupathi has a dorsal coloration of dark brown and light brown on the head with dark and light brown marbling, while N. sahyadrensis has a slight purple tinge (Janani et al. 2017).

The male advertisement call of the two species also differ in that the call of N. bhupathi has more notes per minute, longer notes, a shorter interval in between notes, and a higher frequency than N. sahyadrensis. The notes per minute of N. bhupathi consisted of 25 - 27 notes compared to the 21 - 24 notes of N. sahyadrensis. The note duration, interval between notes, and note frequency of N. bhupathi are 0.28 - 0.466 seconds, 1.056 - 3.154 seconds, and 1.2 - 1.8 kHz respectively, compared to the respective values of N. sahyadrensis which are 0.211 - 0.417 seconds, 1.55 - 3.44 seconds, and 0.6 - 1.4 kHz. The biggest difference in the calls is in that in N. bhupathi each note consists of four pulses while in N. sahyadrensis each note consists of three pulses with a 0.1 second pause between the second and third pulse. Finally, N. bhupathi appears to be smaller overall than N. sahyadrensis (Janani et al. 2017).

Lastly, the two species can be differentiated based on breeding season. While N. sahyadrensis breeds during the southwest monsoon, N. bhupathi breeds during the northeast monsoon (Janani et al. 2017).

There are no discernible differences between the tadpoles of N. bhupathi and N. sahyadrensis (Janani et al. 2017).

Nasikabatrachus bhupathi has a dorsal coloration of dark brown and a dorsal head coloration of light brown with distinct dark brown and light brown marbling. The abdominal skin is a faintly marbled greyish-white color. The palms are brown and the palmar tubercles are a pale white color. The sclera in N. bhupathi’s eyes form a blue ring (Janani et al. 2017).

For the tadpoles, the color of the dorsum varies from medium brown to dark brown. The completely metamorphosed individuals have the same coloration but with brown and black mottles. The ventrum is a pale white color, which becomes opaque and pale white as the tadpole metamorphoses (Janani et al. 2017).

At the time of its description there were too few specimens to determine variation.

Distribution and Habitat

Country distribution from AmphibiaWeb's database: India

View distribution map in BerkeleyMapper.

Nasikabatrachus bhupathi is found on the eastern slopes of the Western Ghats in India. Its currently known distribution is restricted to three highly seasonal second order streams. Nasikabatrachus bhupathi lives in an environment with sporadic rainfall and ephemeral streams that only have flowing water for 3 - 4 months (October to January) out of the year. The streams that N. bhupathi tadpoles were found in have open canopy and varying sizes of rocks in the stream bed (Janani et al. 2017).

Life History, Abundance, Activity, and Special Behaviors

Nasikabatrachus bhupathi spends most of their lives living and feeding underground in moist burrows, only to come to the surface during breeding (Janani et al. 2017).

The breeding calls of N. bhupathi are synchronous to monsoonal showers from October to January with the peak monsoonal showers are from October to November. The males start to call during the rain showers and for a couple of minutes afterwards. Males were found calling from their burrows, which were found within less than 5 m from the stream along stream banks. Often, other breeding males would join in on the calls of other males, creating a mating chorus (Janani et al. 2017).

Advertisement calls of N. bhupathi were recorded approximately 5 - 8 cm into of their burrows from the entrance. The calls consisted of 25 - 27 notes per minute with each note ranging 0.28 - 0.466 seconds and the time interval between notes ranging from 1.056 - 3.154 seconds. The frequency of the notes ranged from 0.6 - 1.4 kHz with the calls becoming more intense and frequent as rainfall intensified (Janani et al. 2017).

Trends and Threats

Since N. sahyadrensis and N. bhupathi are very similar, they likely face similar threats. Tadpoles of N. sahyadrensis are endangered due to the over-harvesting of tadpoles by local people for food (Ashish and Biju 2014).

Relation to Humans

The closely related congener of N. bhupathi, N. sahyadrensis is endangered due to consumption by tribal locals. The tadpoles are considered a delicacy and are harvested each season for their alleged health benefits, such as curing tuberculosis, or for their aphrodisiac qualities (Ashish and Biju 2014). Because the tadpoles of N. bhupathi, and N. sahyadrensis are not distinguishable from each other, it is assumed that the tadpoles of N. bhupathi are also caught for consumption and are at equal risk.

Possible reasons for amphibian decline

Intentional mortality (over-harvesting, pet trade or collecting)

Comments
The species authority is: Janani, S.J., Vasudevan, K., Prendini, E.P., Dutta, S.K., Aggarwal, R.K. (2017). ''A New Species of the genus Nasikabatrachus (Anura, Nasikabatrachidae) from the Eastern Slopes of the Western Ghats, India.'' Alytes, 34(1-4), 1-19.

The K2P genetic distances between N. bhupathi and all other species of the family Sooglossoidea was inferred from the Bayesian inference and supported by Maximum Likelihood analysis. The distance between the partial 16S rRNA gene domain between N. bhupathi and N. sahyadrensis was 3.5 percent, which is higher than the 3 percent cut off value for species level delimitation based on genetic distances. Also, the K2P genetic distance at the partial 12S rRNA gene domain between the two species ranged from 5.6 - 6.7 percent and the distance at the longer fragment of 16S and 12S rRNA gene was 6 percent and 5.9 percent respectively (Janani et al. 2017).

The species epithet is named after Dr. S. Bhupathy who passed away in an accident while conducting herpetological surveys in Western Ghats (Janani et al. 2017).

This frog was the second species in its genus to be described. Speciation between N. bhupathi and its other known congener, N. sahyadrensis is hypothesized to have been caused by breeding during different monsoon seasons. Nasikabatrachus bhupathi breeds during the northeast monsoon while N. sahyadrensis breeds during the southwest monsoon (Janani et al. 2017).

References

Ashish, T., Biju, S. D. (2014). ''Tadpole consumption is a direct threat to the endangered purple frog Nasikabatrachus sahyadrensis.'' Salamandria, 51(3), 252 - 258.

Janani, S.J., Vasudevan, K., Prendini, E.P., Dutta, S.K., Aggarwal, R.K. (2017). ''A New Species of the genus Nasikabatrachus (Anura, Nasikabatrachidae) from the Eastern Slopes of the Western Ghats, India.'' Alytes, 34(1-4), 1-19.

Species Account Citation: AmphibiaWeb 2020 Nasikabatrachus bhupathi <https://amphibiaweb.org/species/8667> University of California, Berkeley, CA, USA. Accessed Nov 5, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 5 Nov 2024.

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