Description
Rana neba is a brown medium-sized frog. The range for snout-vent length is 37.7 - 48.3 mm for males and 43.9 - 45.6 mm for females. The snout is mildly pointed on a head that’s more wide than long. Tympanum is distinguishable and about 2/3 of the diameter of the eye. The supra-tympanic fold is thin. Paired thin curve dorsolateral ridges are found behind the tympanum to the groin. The nostril is more near the eye than the moderately pointed end of the snout. Loreal region is concaved. The distance between the nasal cavities is larger than the distance between the orbits. Canthus rostralis is not pointed. The dorsum is smooth. Thigh is granulated on the underside, side, and near the hind end of the thigh (Ryuzaki et al. 2014).

Relative length of the fingers are 2 < 1 < 4 < 3. The fingers are free with subtle rounded tips. The first finger is bent inwards towards the middle. Two nuptial pads are found with one on the inner side of the base of the first finger and the other with on the upper side of the middle part of the first finger (males). Inner side of arms is very thick. Subarticular tubercles are well developed and there are two, distinct palmar tubercles (Ryuzaki et al. 2014).

Relative length of the toes are 1 < 2 < 5 < 3 < 4. Toe tips are small and rounded. The hind limb is approximately 1.6 times longer than the snout-vent length. The femur is a little smaller than the tibia. When the legs are folded at a right angles to the body axis, the tibio-tarsal articulations overlap slightly. When the hind limbs are stretched forward along the body axis, the tibio-tarsal articulations reach the eye (Ryuzaki et al. 2014).

Rana neba is distinguished from its sibling species, Rana tagoi, through small differences in morphological components and by its advertisement call. Compared to R. tagoi, the snout to nostril distance is larger and there is smaller webbing on fingers 4, and toes 4 and 5. The advertisement calls of R. neba is of higher frequency and the calls of R. tagoi are of lower pitch (Ryuzaki et al. 2014).

In life, the dorsal side is reddish brown. The ventral side is white with small grey dots from throat to venter. Upside-down black triangles are found between eyelids and upside-down black V found behind the triangle (males). Cross black bands are on forearms, thighs, tibias, and feet. Sides of canthus rostralis and tympanic area are both black. Both upper jaw and nuptial pad are white (Ryuzaki et al. 2014).

Rana neba exhibits sexual dimorphism. Male characters include: presence of nuptial pad, thick forearm, more developed palmar tubercles, upended black triangle mark between eyelids, and upended black V mark on the back behind the head. Females characteristics include: no distinct black marking on the top side, less conspicuous cross bars on the thigh, tibia, and tarsus, and mottling pattern of reddish and yellowish brown on the top side. Light and black mottling pattern vary on the bottom side for both males and females. Size does not appear to differ between the sexes (Ryuzaki et al. 2014).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Japan

View distribution map in BerkeleyMapper.

Rana neba currently reside in Japan, specifically within 40 km from Mt. Chausu. Distribution occurs in the southern portion of Nagano Prefecture such as the following: Neba-mura, Urugi-mura, Tenryu-mura, Anan-cho, Hirarya-mura, Achi-mura, Shimojo-mura, Takagi-mura, and Oshima-mura. Some occurrences include areas near Aichi Prefectures such as the following: Toyone-mura, Shitara-cho, and Asuke-cho in Toyota. In addition to that, some were found in Shizuoka Prefecture: Inasa-cho in Hamamatsu (Ryuzaki et al. 2014).

Life History, Abundance, Activity, and Special Behaviors
Advertisement calls of R. neba mainly consist of pulse groups, containing 2 – 4 notes. In the two note call, the first note is short and low in frequency. The second note is longer with more pulses and at a higher frequency of ~5kHz and ~8kHz. The more common three note call was similar to the two-note call. The three note call is considered representative of the calls of R. neba. There are two types of four note calls, one with a short note and one with a longer note with slow pulses and at a low frequency. Multi-note calls were similar to the two note and three note calls structure but the longer four note call had a slower pulse repetition rate. Rana neba were also heard calling 5 – 11 successive notes at a rate of 3.3 notes per second. All notes were similar in length to the second notes of the calls described above and had a distinct high frequency of ~5 kHz but had a dominant frequency of 1.7 and 1.3 kHz (Ryuzaki et al. 2014).

Trends and Threats
Currently unavailable.

Comments
Ryuzaki, M., Hasegawa, Y., Kuramoto, M. A new brown frog of the genus Rana from Japan (Anura: Ranidae) revealed by cytological and bioacoustic studies. Alytes 31:49-58

Rana neba and Rana tagoi tagoi have small mean nucleotide differences in their mitochondrial cytochrome b gene sequences, they differ in the number of chromosomes (n = 28 vs. n = 26 respectively) and do not produce hybrids capable of reproduction (Ryuzaki et al. 2014).

Rana neba (Ryuzaki et al. 2014).

Rana neba may possibly hold two characteristics that are unique to them: the 2n = 28 karyotype and the high-pitched advertisement call (Ryuzaki et al. 2014).

References

Ryuzaki, M., Hasegawa, Y., Kuramoto, M. (2014). ''A new brown frog of the genus Rana from Japan (Anura:Ranidae) revealed by cytological and bioacoustic studies.'' Alytes, 31, 49-58.

Species Account Citation: AmphibiaWeb 2015 Rana neba <https://amphibiaweb.org/species/8277> University of California, Berkeley, CA, USA. Accessed Nov 22, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 22 Nov 2024.

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