Description
Mature males attain snout-vent lengths (SVL) of 20.6 – 24.1 mm and mature females up to 23.1 mm in SVL (Manamendra-Arachchi and Pethiyagoda 2005). Head dorsally flat, tympanum distinct, oval and oblique. Snout angle category 6 (angle of snout ~ 100º). Interorbital and internarial spaces flat. Vomerine ridge present or absent: when present, bearing a few small teeth, angled at about 60º relative to body axis, shorter than the distance between them. Cephalic ridges absent. Toes medially webbed. Tarsal fold absent. Calcar absent. Snout and interorbital area smooth. Side of head and dorsum with glandular warts. Flank granular. Dorsal areas of forelimb, thigh, shank and foot smooth. Throat, chest, belly and underside of thigh granular. Nuptial pad absent in males, but inner vocal slits present (Manamendra-Arachchi and Pethiyagoda 2005).

Diagnosis: P. rus closely resembles P. popularis, however, the two species can be demarcated from the following morphological characters: P. rus can be distinguished from P. popularis by the presence of black patches on anterior thigh, snout angle category 6, nuptial pad absent, and head dorsally flattened vs. absence of black patches on anterior side of thigh, snout angle category 5, nuptial pad present and head dorsally convex in P. popularis (Manamendra- Arachchi and Pethiyagoda 2005).

Colour in life: Dorsum dark brown with light-brown patches. Tympanic region dark brown with pale-brown and ashy patches, the tympanum itself reddish or dark brown. Upper lip dark brown with pale and ashy brown patches. Loreal region dark brown. Upper flank chestnut brown with dark-brown patches; lower flank pale yellow with dark-brown patches. Dorsal and lateral parts of forelimb, dorsal part of thigh, dorsal part of shank and dorsal part of foot brown with dark-brown crossbars. Thigh brown with dark-brown patches on posterior edge. Throat, margins of throat, vocal sacs, chest, belly and underside of thigh pale yellow yellowish-orange with dark-brown pigments. Webbing dark brown. (Manamendra-Arachchi and Pethiyagoda 2005).

Colour in alcohol: (based on holotype, WHT 3474) Dorsum dark brown with light-brown patches. Tympanic region dark brown with pale-brown patches, the tympanum itself reddish-brown. Upper lip dark brown with pale-brown patches. Loreal region dark brown. Upper flank light brown with dark-brown patches; lower flank pale yellow with dark-brown patches. Dorsal and lateral parts of forelimb, dorsal part of thigh, dorsal part of shank and dorsal part of foot brown with dark-brown crossbars. Thigh brown with dark-brown patches on posterior edge. Throat, margins of throat, vocal sacs, chest, belly and underside of thigh pale yellow with dark-brown pigments. Webbing dark brown. (Manamendra-Arachchi and Pethiyagoda 2005).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Sri Lanka

View distribution map in BerkeleyMapper.

This shrub frog was described from two localities around Kandy (500–800 m a.s.l), Sri Lanka; Kiribathkumbura and Pilimatalawa (Manamendra-Arachchi and Pethiyagoda 2005). Subsequent records of this species are Eastern Sinharaja, Uda Maliboda, Maha Usakanda (Rathnapura) and Nawalapitya (Meegaskumbura 2012; Paebotuwage et al. 2012; Samarasinghe et al. 2012; Samarasinghe 2012; Wickramasinghe et al. 2012).

Life History, Abundance, Activity, and Special Behaviors

Pseudophilautus rus begins vocalizing around 18:00 h and ends around 06:30 h. This species mainly inhabits low vegetation, such as grass, logs, dry leaves of ferns, and deep crevices of short tree trunks and short shrubs, 0.1–2 m above the ground. This species is common in home gardens around Kandy and Nawalapitiya. P. rus is known to share habitat with P. folicola and P. popularis (Manamendra-Arachchi and Pethiyagoda 2005; Samarasinghe 2012). According to Manamendra-Arachchi and Pethiyagoda (2005), females are relatively cryptic while males can be observed engaged in calling duets and territorial aggression. The advertisement call was the most common call emitted by P. rus (Samarasinghe 2012).

Reproductive behaviour: P. rus is a direct developer (Bahir et al. 2005).

Call: The advertisement call consists of a short, multi-pulsed note. This note is amplitude modulated, with amplitude decreasing over time. The call duration is 27–36 ms and the intercall interval is between 4.29–10.36 s. Each call consists of 4–10 prominent pulses and the pulse rate ranged from 129.03–312.50 s-1. The lower frequency, upper frequency and the dominant frequency are 1.6–2.0 kHz, 3.3–3.8 kHz and 2.4–3.2 kHz respectively (Samarasinghe 2012).

Although P. rus closely resembles P. popularis, these two species can also be distinguished by their advertisement calls as well. P. rus has a shorter call duration 27–36 ms vs. 47–78 ms, higher pulse rate 129.03–312.50 s-1 vs.78.13–178.08 s-1, and also having a lower frequency range: lower, upper and dominant frequencies, 1.6–2.0 kHz, 2.5–3.7 kHz and 2.4–3.2 kHz vs. 2.5– 3.7 kHz, 3.1–5.7 kHz and 3.3–4.1kHz respectively in P. popularis (Samarasinghe 2011; 2012).

Trends and Threats

P. rus is considered a near threatened species, though it is common in human-modified habitats. The major threat to P. rus populations is habitat destruction and fragmentation. Although several new locations have been reported subsequent to its discovery, it is evident that its distribution within the lowlands is severely fragmented. This species is also at risk due to the use of agricultural pesticides, toxins and pollutants.

Possible reasons for amphibian decline

General habitat alteration and loss
Urbanization
Habitat fragmentation
Local pesticides, fertilizers, and pollutants

Comments
The species authorities for P. rus is Manamendra-Arachchi and Pethiyagoda (2005).

The species epithet, rus, is Latin for ‘fields, countryside’, an allusion to this species occurring in home gardens in the suburbs of Kandy.

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 (2012). 2012 IUCN Red List of Threatened Species. . Downloaded on 11 July 2012.

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.

Meegaskumbura, M., Meegaskumbura, S., Gunatilleke, S., Manamendra-Arachchi, K., Bowatte, G., Gunathilaka, T., and Bandara, C. (2012). ''Conservation and Biogeography of Threatened Amphibians of Eastern Sinharaja.'' FrogLog, 100, 12–14.

Peabotuwage, I., Bandara, I. N., Samarasinghe, D., Perera, N., Madawala, M., Amarasinghe, C., Kandambi, H. K. D., and Karunarathna, D. M. S. S. (2012). ''). Range extension for Duttaphrynus kotagamai (Amphibia: Bufonidae) and a preliminary checklist of herpetofauna from the Uda Mäliboda Trail in Samanala Nature Reserve, Sri Lanka.'' Amphibian and Reptile Conservation, 5(2), 52–64.

Samarasinghe D, Karunarathna D M S S, Peabotuwage I, Madawala M, Perera N, Kandambi D, Bandara N and Amarasinghe C. (2012). ''Amphibian Composition of the Uda Mäliboda Trail in the Samanala Nature Reserve (SNR), Sri Lanka: A Cautionary Note.'' FrogLog, 101, 50-52.

Samarasinghe, D. J. S. (2011). ''Description of the complex advertisement call of Pseudophilautus popularis (Manamendra-Arachchi & Pethiyagoda, 2005) (Amphibia: Rhacophoridae).'' Zootaxa, 3002, 62-64.

Wickramasinghe, M., Bambaradeniya C., Vidanapathirana, D., and Karunarathna S. (2012). ''Diversity of Herpetofauna in Mahausakande: A Regenerating Rainforest in Sri Lanka.'' Occasional Paper, (1), 1-40.

Species Account Citation: AmphibiaWeb 2012 Pseudophilautus rus: Kandyan shrub frog <https://amphibiaweb.org/species/6493> University of California, Berkeley, CA, USA. Accessed Feb 2, 2025.

Citation: AmphibiaWeb. 2025. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 2 Feb 2025.

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