Description
Although at least five individuals of this species has been found, only one individual of this species has been described, an adult female with a snout-to-vent length of 40.9 millimeters. The throat and the sides of its head are smooth, and the back of its head is flattened. It has a smooth snout that is oval shaped when viewed from the side, and it is angled at 105 degrees. The edges of its eyes are rounded, and the region between its eyes and nostrils is concave. The region between both eyes, as well as the region between both nostrils, is also concave. The region between the eyes is also smooth in texture. The tympana are distinct, slanted, and oval shaped. The body is elongated, and it has a smooth back and stomach. The lower half of the region between the ribs and the hip has a grainy texture, and glandular warts on the upper half. The backsides of its forelimbs and thighs are smooth, as well as the undersides of its thighs. The lower part of its legs and feet are also smooth, albeit interspersed with a few glandular warts (Manamendra-Arachchi and Pethiyagoda 2005).

This species bears a striking resemblance to Pseudophilautus ocularis, however there are a few morphological traits which can help differentiate between the two closely related species. Pseudophilautus lunatus has a rough tongue, dermal fringe on fingers, a smooth back, and crossbars on its limbs, whereas P. ocularis does not (Manamendra-Arachchi and Pethiyagoda 2005).

In life, the sides of its eye, the lower part of its eye, and the lower tympana are brown. The region between its eyes is also brown, and additionally has black spots. It has a white chin and chest with dark brown patches. Its mid-back is reddish brown, and the sides of its back are greyish brown with black patches. It has a greyish white abdomen, and a dark brown groin. The undersides of the limbs are dark brown with greyish spots. The toe-tips are dark grey, whereas the backside of the fingertips are greyish yellow (Manamendra-Arachchi & Pethiyagoda 2005).

In alcohol, the backside of its head, the region between the eyes, and the region between the eye and nostril are brown. The tympana are faint yellow and brown. It has a faint yellow throat with dark brown patches, whereas the sides of the throat are faint yellow with dark brown banding. Its upper lip is dark brown with faint yellow patches. Its mid-back is faint brown, and the sides of its back are black. Its chest is faint yellow and has dark brown spots. The upper half of the region between the ribs and the hip is dark brown and spotted black, whereas the lower half is faint yellow with brown and black patching. The groin is brown and faint yellow. The back and sides of the forelimbs are brown and faint yellow, and have dark brown crossbar markings. The backsides of its legs are brown and have dark crossbar markings. The backsides of the feet are brown with black patching. The part of the thigh towards the rear is brown, faint yellow, with black patching, whereas the part of the thigh towards the head is only brown. The ventral side of the thigh is brown with faint yellow spotting, and it has dark brown webbing (Manamendra-Arachchi & Pethiyagoda 2005).

There is no information available on variation within the species.

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Sri Lanka

View distribution map in BerkeleyMapper.

Pseudophilautus lunatus is endemic to Sri Lanka and occurs in a very small area of wet-zone rainforest near Suriyakanda, in the Handapan Ella Plains. Its range is from 10 km² to 28 km² and the species occurs at elevations of around 1270 m. It is known to occur only in this location (Manamendra-Arachchi & Pethiyagoda 2005, IUCN SSC Amphibian Specialist Group 2014).

Life History, Abundance, Activity, and Special Behaviors

Pseudophilautus lunatus is a rare terrestrial frog species. It was first discovered on the underside of a plant one meter above the ground. It does not appear to be water-dependent, but lives in a humid, wet forest. Presumably, breeding is dependent on periods of high humidity and/or increased rainfall (Manamendra-Arachchi and Pethiyagoda 2005, Bahir et al. 2005).

It is also presumed this species is a direct-developing frog as are other Pseudophilautus (IUCN SSC Amphibian Specialist Group 2014).

Little has been observed about this particular species, but some Pseudophilautus are known to dig terrestrial nests in dirt on the ground to deposit their eggs. These clutches range from just a few to over a hundred eggs. Other observed Pseudophilautus species deposits their eggs on the underside of leaves. Pseudophilautus lunatus may fit into one of these two behaviors. Parental care has not been observed in either nesting behavior (Bahir et al. 2005).

In most Pseudophilautus species, the male will perch above ground and make vocalizations throughout the whole year, most commonly at night and during times of rainfall and high humidity, to attract females for breeding. Males will remain perched throughout courtship until they make eye contact with a female, at which point the male will try to mate with the female. Pseudophilautus breed by axillary amplexus (Bahir et al. 2005).

Trends and Threats
Follow up surveys in 2014 found 4 individuals over 4 hours, and there is no data to suggest the species is trending towards decline. However, as it is only found in a very limited rainforest fragment, habitat loss and deforestation are the major threats. Habitat degradation caused by plant harvesting and illegal mining is also a significant issue (IUCN SSC Amphibian Specialist Group 2014, Pethiyagoda 2012).

This species has been found in the Sinharaja World Heritage Site and the Morningside Forest Reserve. Morningside Forest Reserve receives some degree of government protection, however only the Sinharaja World Heritage Site is an official conservation area. Pressure from land use within the reserve is a major problem, mostly due to a tea/cardamom plantation located at the center of the reserve. With the plantation comes illegal clearing of understory in order to incorporate cultivation sites. The site is in need of adequate protection, which could come from the incorporation of Morningside into the Sinharaja World Heritage Site (Manamendra-Arachchi and Pethiyagoda 2005, IUCN SSC Amphibian Specialist Group 2014).

Possible reasons for amphibian decline

General habitat alteration and loss
Habitat modification from deforestation, or logging related activities
Intensified agriculture or grazing
Habitat fragmentation
Local pesticides, fertilizers, and pollutants

Comments
The species authority is: Manamendra-Arachchi, K., & Pethiyagoda, R. 2005. The Sri Lankan shrub-frogs of the genus Philautus Gistel, 1848 (Ranidae: Rhacophorinae), with description of 27 new species. The Raffles Bulletin of Zoology. 12: 163-303.

This species is found on the Handapan Ella plains, or ‘the moonlit plains’, with which it receives its name. Lunatus is derived from the Latin word for moon: lunar (Manamendra-Arachchi and Pethiyagoda 2005).

References

Bahir, M. M., Meegaskumbura, M., Manamendra-Arachchi, K., Schneider, C. J., and Pethiyagoda, R. (2005). ''Reproduction and terrestrial direct development in Sri Lankan shrub frogs (Ranidae: Rhacophorinae: Philautus).'' The Raffles Bulletin of Zoology, 12, 339-350. [link]

IUCN SSC Amphibian Specialist Group. 2014. Pseudophilautus lunatus. The IUCN Red List of Threatened Species. Version 2014.3. www.iucnredlist.org. Downloaded on 14 February 2015.

Manamendra-Arachchi, K., and Pethiyagoda, R. (2005). ''The Sri Lankan shrub-frogs of the genus Philautus Gistel, 1848 (Ranidae: Rhacophorinae), with description of 27 new species.'' Raffles Bulletin of Zoology, Supplement 12, 163-303.

Pethiyagoda, R. 2012. Biodiversity conservation in Sri Lanka's novel ecosystems. Ceylong Journal of Science (Bio. Sci.). 41 (1): 1-10.

Species Account Citation: AmphibiaWeb 2015 Pseudophilautus lunatus: Afro-Asian Tree Frog <https://amphibiaweb.org/species/6500> 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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