Description
Polypedates ranwellai is a moderate sized frog with snout vent lengths of 40.5 – 48.8 mm in males and 67.9 mm in females. This species is tentatively assigned to the genus Polypedates because it possesses the following morphological characters: bony co-ossification on the skull; nasal club-shaped; tips of digits with circum-marginal grooves; and fingers basally webbed. It is the only member in the genus possessing the following combination of characters: a series of teeth on maxilla, progressively changing orientation from horizontal to vertical, from posterior end to anterior; a laterally-curved spine in the quadratojugal bone (externally seen as a protrusion at the proximal end of the jaw); bony co-ossification on the skull resulting in four dorsal spines, one each in the squamosal bones and two in the frontoparietal bone (externally seen as protrusions in the parietal area). Apart from the above characters the species can easily be distinguished from all other congeners in the island from its smallest choanae, which are slightly smaller than its odontophores. When compared with all 22 extant species of the genus Polypedates, this species can be readily distinguished from the diagnostic characteristics in the skull because none of its congeners possess any of the said characteristics of the skull. (Wickramasinghe et al. 2012).

Colour in life. The body colour varies from black spots on white to green, yellow being more frequent; dorsal part of head and dorsum, and upper part of flank with very small black spots on bright luminous yellow; lower part of flank marbled with black and off-white; loreal and tympanic regions and tympanum with small black spots on luminous yellow; upper lip small and moderate, black spots on light yellow; forelimb with faint black stripes on yellow and small black spots all over, upper arm with two-three stripes and lower arm with one stripe; lower arm having faint black stripe on yellow with black spots; tibia and tarsal with three faint black stripes on yellow and scattered small black spots, occasional stripe on knee; posterior part of femur marbled with black and whitish yellow, ventral part white with shaded black; throat, vocal sacs, chest and belly all white; margin of throat whitish yellow with black spots; webbing dark brown (Wickramasinghe et al., 2012).

Colour in alcohol. Colour of spots and stripes degraded a little from above. Body colour turned to light grey. Female colour pattern is the same as the male both in life and after preservation (Wickramasinghe et al. 2012).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Sri Lanka

View distribution map in BerkeleyMapper.

The only known population of Polypedates ranwellai is found in Gilimale forest reserve in the Sabaragamuwa province of Sri Lanka at elevation 150m above sea level (Wickramasinghe et al. 2012).

Life History, Abundance, Activity, and Special Behaviors
They are commonly found near forest edges with an open canopy in more numbers than in the closed canopy forest. They are commonly observed perching on branches of trees and shrubs 1–10 m above ground level. Some are observed on the forest floor as well (Wickramasinghe et al. 2012).

Breeding. A pair of P. ranwellai have been observed in axillary amplexus on a branch 1.5 m above ground in the subcanopy shrubs. Slowly the pair came down the branch onto the ground. Then the female started slowly moving backwards burrowed into the leaf litter and upon reaching the soil layer, the female started slowly digging with a movement of her hind limbs but due to low light conditions and camouflaged nature they could not be relocated. However, this observation was not sufficient to conclude if they are foam-nesters or a direct developing species (Wickramasinghe et al. 2012). Other members of Polypedates are known to be foam-nesters (e.g., Polypedates leucomystax).

Comments
Polypedates ranwellai is named after Sanjeewa Ranwella, a medical doctor by profession, for his contributions towards conserving Gilimale forest reserve and conservation of wildlife in general (Wickramasinghe et al. 2012).

As of yet, no molecular phylogenetic analysis has been done on this species to determine its relation to other members of the same genus. When such analysis is done, it is highly likely that this species may be assigned to a different genus or a totally new genus of its own.

References

Wickramasinghe L.J.M., Munindradasa D.A.I. and Fernando P. (2012). "A new species of Polypedates Tschudi (Amphibia, Anura, Rhacophoridae) from Sri Lanka." Zootaxa, 3498, 63-80. [link]

Species Account Citation: AmphibiaWeb 2021 Polypedates ranwellai: Ranwella's Spined Treefrog (English) <https://amphibiaweb.org/species/7911> University of California, Berkeley, CA, USA. Accessed Dec 4, 2022.

Citation: AmphibiaWeb. 2022. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 4 Dec 2022.

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