Description
Platymantis navjoti is a small and slender frog with a snout to vent length of approximately 21.1 - 26.6 mm for males and 26.4 - 28.8 mm for females. The head width is equal to the width of the body and its length is about 40.1% of the snout to vent length and almost equal (96.6%) to its width. The rounded snout protrudes only slightly over the lower jaw. The length between the center of the eye and narial openings is six times the length between the nostrils and the tip of the snout. The loreal region is slightly concave. The horizontal diameter of the eye is about the same length (92.3%) and as the distance between the snout tip to the anterior point of the eye. The pupils are horizontally ovoid, and the interorbital region is primarily flat, with two low ridges medial to the eyelids. The tympanic annulus is barely distinct and its horizontal diameter is about 44% of the horizontal diameter of the eye. The labial region is slightly flared. The vocal sac is located interior to the jaw angle. The dorsal surface of the body, head, and limbs are entirely smooth. The ventral body surface is also smooth except for a slightly glandular texture on the posterior surface of the groin and the medial ventral surfaces of the thighs. The cloacal region is finely glandular with small supracloacal dermal granules (Diesmos et al. 2020).

The forelimb musculature is not well developed. The enlarged, flat inner metacarpal tubercle is squarish and broad while the outer metacarpal tubercles is think and elongated. The hand length is about 63.9% of the foot length and its palmar surface appears wrinkled. The hands show no signs of interdigital webbing. The fingers are wide and flat with dermal flanges along their entire length, ending with widely expanded terminal discs on Fingers 2 - 4 and a barely expanded disc on Finger 1. Relative finger lengths are 3 > 4 > 2 > 1. Subarticular tubercles are low, flat and barely distinct. The supernumerary tubercles are flat and indistinct and flat. No nuptial pads are present (Diesmos et al. 2020).

The hind limb is long and slender with the tibia length being 63.3% of the snout to vent length. The femur length is 92.5% of the tibia length, and the foot lengthis 81.2% of the tibia length. The dorsal surface of the hind limb and bottoms of the feet are smooth, but the latter are wrinkled in appearance. The tarsal surface is also smooth except for the axial dermal ridge running along its posterior surface, ending in a fleshy conical tubercle on the heel. Relative toe lengths are 4 > 3 > 5 > 2 > 1. The feet contain minute interdigital webbing that barely reaches the first row of subarticular tubercles. Toe discs are not expanded in Toes 1 and 5, and very narrowly expanded in Toes 2 - 4. The subarticular tubercles are well-developed, low, and flat in the subarticular. There are no supernumerary tubercles on the plantar region and barely evident supernumerary tubercles in the metatarsal region (Diesmos et al. 2020).

DIAGNOSIS:

Platymantis navjoti differs from other species within the subgenus Tirahanulap, of which is a part of, in that most Tirahanulap species have a dorsal surface that is variably marked atop a dark brown, tan, or white to bright yellow ground coloration. More specifically, P. isarog, P. lawtoni, P. montanus, and P. subterrestris have distinctive brown and yellow flank areolations. Additionally, P. isarog have a light ventrum with dark reticulate patterning. Lastly, P. sierramadrensis males are generally larger in size (Diesmos et al. 2020).

The advertisement call, both behavior and acoustics, is similar to other species of the subgenus, including P. isarog, P. montanus, P. polillensis, and P. subterrestris, along with other undescribed species. The call of the P. navjoti is most similar to that of P. polillensis, but the two do not overlap in geography (Diesmos et al. 2020).

COLORATION:

Live individuals tend to have either an iridescent emerald green or orange dorsal coloration with irregularly shaped and evenly spaced tiny white dots appearing on the head, body, and limbs. They also have a white dorsal vertebral line that runs between the interorbital and rostral regions. The ventrolateral coloration is bright white and orange and wraps posteriorly on to the ventrum. The ventrum coloration ranges from white to creamy. The tibias contain faint blotches and dark orange patches on their posterior surface. The dorsal surfaces of the terminal discs are yellow with white subarticular flaps. The ventral surfaces of the hands and feet are light green. The iris coloration ranges from creamy reddish to golden brown, and the tympanic region has a slightly darker green color than the dorsum of the green variety (Diesmos et al. 2020).

Specimens preserved after three years tend to have pale yellow to white dorsal and ventral surfaces, with skeletal elements and organs visible through the skin. Preservation also causes the transverse limb bands to disappear and the digital tips to turn a slightly darker yellow (Diesmos et al. 2020).

VARIATION:

Some individuals of the green variety can appear darker with enlarged black markings. Others can have a lime green dorsal coloration with white and orange lateral spots. Orange varieties can be of various shades relative to each other. The prominence of the dark limb blotches can also vary, as does the iris coloration, ranging from pale silvery white to deep bronze or gold (Diesmos et al. 2020).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Philippines

View distribution map in BerkeleyMapper.

This species is known to occur in lower- and upper-montane forests of primary or secondary forests in the Nacolod mountain range of Barangay San Juan, in the Municipality of Sogod of southern Leyte Province, Philippines at 730 - 900 m above sea level. A specimen was also found in an primary forest on the mountains above Ormoc City, Leyte Island, at 850 m above sea level. Another specimen was found in a secondary growth forest on Mt. Huraw in north-central Samar Island, Municipality of San Jose de Buan, at 616 m above sea level (Diesmos et al. 2020).

Life History, Abundance, Activity, and Special Behaviors
Platymantis navjoti can be found on various leaf surfaces that hang 0.5 - 3 m above the forest floor, particularly sapling leaves, fronds of rattan palms, entangled dead leaves, and spaces within curled leaves (Diesmos et al. 2020).

The complex advertisement call of adult males occurs every several minutes with the frog perching upright to inflate its vocal sac, then lowers its head and remains silent to rest for several minutes before repeating the call. The finely pulsed, cricket-like, chirp call consists of 8 - 14 chirps over 20 - 30 seconds. Within the call, the pulsed chirp repetition rate was 0.49 - 0.64 chirps with individual chirps or notes containing 3 - 5 subpulses; the highest amplitude occurring in the middle subpulses. Chirps last 180 - 230 ms and had two spectral call components. The lower frequency component is between 0.99 - 1.77 kHz and has a duration of 75 - 150 ms while the higher component ranges from 2.2 - 3.05 kHz and lasts the full duration of each note (for more details see Diesmos et al. 2020).

Adult females lay their clutches of about eight to twelve eggs on top of leaves, and adult males are known to guard the clutch (Diesmos et al. 2020).

This species lives in sympatry with local Hylarana, Kaloula, Kurixalus, Limnonectes, Megophrys, Nyctixalus, Occidozyga, Oreophryne, Pelophryne, Philatus, Platymantis, Pulchrana, Rhacophorus, Rhinella, and Sanguirana species (Diesmos et al. 2020).

Larva
The species reproduces via direct development (Diesmos et al. 2020).

Trends and Threats
Frogs of the subgenus Tirahanulap are known to be rare or completely absent in logged forests, likely due to sunlight penetrating through the canopy gaps and increasing the forest floor temperatures. The rapid deforestation rate of Leyte Island’s lower-montane and lowland forests will most likely threaten this and other forest-obligate and endemic frog species (Diesmos et al. 2020).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities

Comments

PHYLOGENETIC RELATIONSHIPS:

Based on morphological and bioacoustical data, P. navjoti is a member of the P. hazelae species group. However, at the time of the species description, P. navjoti was the only known member of its subgenus to be found in Leyte and Samar islands (Diesmos et al. 2020).

This species belongs to the genus Platymantis (Philippine Forest Frogs), which is further categorized into five phylogenetically-defined subgenera: Platymantis (Masked Frogs), Lupacolus (Ground Frogs), Tahananpuno (Rain Frogs), Lahatnanguri (Variable Forest Frogs), and Tirahanulap (Cloud Frogs), the last of which P. novjati belongs (Diesmos et al. 2020).

ETYMOLOGY:

The species epithet, “novjati,” is in honor of the late Navjot Sodhi, a professor from the National University of Singapore and one of Southeast Asia’s most respected conservation scientists (Diesmos et al. 2020).

References
Diesmos, A.C., Scheffers, B.R., Mallari, N.A.D., Siler, C.D., Brown, R.M. (2020). A new forest frog of the genus Platymantis (Amphibia: Anura: Ceratobatrachidae: Subgenus Tirahanulap) from Leyte and Samar Islands, Eastern Philippines. Zootaxa, 4830(3), 573-591. DOI:10.11646/zootaxa.4830.3.6. [link]

Species Account Citation: AmphibiaWeb 2023 Platymantis navjoti: Navjot Sodhi's Cloud Frog <https://amphibiaweb.org/species/9245> University of California, Berkeley, CA, USA. Accessed Apr 19, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 19 Apr 2024.

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