Description
Nyctibatrachus jog is a medium sized frog with snout-vent lengths between 33.1 - 39.0 mm. The head is wider than it is long and the body is robust. Supratympanic folding of the skin on the body is prominent from posterior corner of upper eyelid to the shoulder. Forearm is shorter than the hand. Finger and toe disks are well developed. Third finger and fourth toe discs have dorso-terminal groove with a distally rounded cover. Third finger discs with dorso-terminal groove are 3.2 times wider than the finger. Hind limbs are moderately long and the lower part of the legs is shorter than the foot length. Vocal sacs of males are poorly distinguishable externally when deflated, but expand and inflate laterally when calling. It can be further distinguished by its wrinkled dorsal skin, interrupted dorsolateral folds, weakly webbed toes, and femoral glands in males (presumably only in the breeding season as with other Nyctibatrachus (Biju et al. 2011).

Dorsum is a uniform black color with light grey patches. A pair of faint brown, longitudinal dorsal bands extends from the back of the eyelids to the middle of the dorsum. Limbs are dorsally light grey, and forelimbs, hind limbs, fingers and toes have black cross-bands. Thighs have dark grey patches and feet and webbing are dark grey. Abdominal sides are uniform grey. The throat and femoral glands are reddish-brown. Black or bluish-black liver is externally visible on the ventral side through the skin (Biju et al. 2011).

In addition, to morphological distinctions, mitochondrial DNA analysis shows N. jog with 4.2% divergence from N. petraeus in uncorrected pairwise comparisons within Nyctibatrachus (Biju et al. 2011).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: India

View distribution map in BerkeleyMapper.

Nyctibatrachus jog is found in Western Ghats mountain range along the western side of India. It has only been found by Jog Falls in Mavingundi, Karnataka State, at 600 m elevation. Specimens were collected from vegetation near seasonal streams during the monsoon season (Biju et al. 2011).

Life History, Abundance, Activity, and Special Behaviors
Male Nyctibatrachus jog attracts the female with his advertisement call from the oviposition site, usually about 0.5 -2 m above still or flowing water in branches or leaves. The male then takes the female in an intense amplexus lasting more than 20 minutes compared to just a loose amplexus between other species in the genus. Immediately after the male has dismounted the female, she produces the egg group over a period of only a few seconds and attaches the eggs on vegetation overhanging water or on sheer rock surfaces. Thus, there is an absence of physical contact during the egg-laying process.

The female subsequently leaves the egg group and the male sits over the eggs. Both the female and male are present at the oviposition site during the day and night. The reason for both being present is unclear, but it is assumed that the adults are both present to hydrate the clutch, as the adults were regularly observed positioned directly on top of the egg groups. Nyctibatrachus jog showed no signs of aggressive or defensive behavior when the oviposition site was approached.

Eggs take 8-9 days to hatch and resulting tadpoles of length 8 mm are black. Complete metamorphosis into froglets is achieved by days 31-33. They are most active at night (Biju et al. 2011).

Trends and Threats
Biju et al (2011) comment that the pattern of localized, possibly highly endemic, specialized montane species as seen in the Nyctibatrachus indicate that it is highly likely outside of strictly protected areas, these species are vulnerable to the forest fragmentation and habitat alterations that are ongoing with the encroachment of human activity in the Western Ghats.

Possible reasons for amphibian decline

Habitat modification from deforestation, or logging related activities
Habitat fragmentation

Comments
The species is named after Jog Falls, where the type series was discovered (Biju et al. 2011).

References

Biju, S.D., Van Bocxlaer, I., Mahony, S., Dinesh, K.P., Radhakrishnan, C., Zachariah, A., Giri, V., and Bossuyt, F. (2011). ''A taxonomic review of the Night Frog genus Nyctibatrachus Boulenger, 1882 in the Western Ghats, India (Anura: Nyctibatrachidae) with description of twelve new species.'' Zootaxa, 3029, 1-96.

Species Account Citation: AmphibiaWeb 2011 Nyctibatrachus jog: Jog’s Night Frog <https://amphibiaweb.org/species/7715> University of California, Berkeley, CA, USA. Accessed Nov 29, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 29 Nov 2024.

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