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Description
Rentapia hosii is a treefrog with a type locality from Mount Dulit, Sarawak (Boulenger 1892). Females have a snout-vent-length range between 88.6 - 105.0 mm and males are between 50.0 - 80 mm (Inger and Voris 2008, Chan et al. 2020). Male R. hosii are similar in morphology to other Rentapia from their complex, but females are easily distinguishable from other species. Females have a large, sturdy body and build. Their head is wide with a flat top. The snout is angular and shortened when viewed from the top. From a lateral view, the lower jaw slightly protrudes. The nostrils are long, arranged diagonally, and are located at the tip of the snout. They have distinct, rounded canthus rostralis and large eyes. The tympanum is distinct, oval, high, and the rim is elevated slightly. The forelimbs are long, and the hands have large palmar tubercles. The fingers are webbed at the base and the fingertips expand into discs that do not have circummarginal groves. The relative finger lengths are I < II < IV < III and they have distinct, round, basal subarticular tubercles and indistinct subarticular tubercules further up the fingers. There is one subarticular tubercle on fingers I and II and two subarticular tubercles on fingers III and IV. The hind limbs are sturdy and robust. The inner metatarsal tubercle is large and round while the outer is distinct and half the size of the inner. The toes are webbed with a formula of I 0 1 II 0 2 III 0 2.5 – 3 IV 2.5 – 3 1 V, and the tips end in small discs with circummarginal grooves. The toes have distinct, round subarticular tubercles. The skin has low tubercles on the flanks, on the surface of the limbs, and on the upper eyelids (Chan et al. 2020).

Rentapia hosii was once considered a widespread southeast Asian species found throughout southern Thailand, Peninsular Malaysia, Sumatra, and southern Borneo. However, recent molecular analysis revealed that Peninsular Malaysian and southern Thailand populations are a different species, identified in 2020, that is named R. flavomaculata. True R. hosii have been confirmed in the Sarawak region of southern and western Borneo (Malaysia), while R. everetii is only found in northeastern Borneo. Male Rentapia are difficult to distinguish, except by call, but female Rentapia can be differentiated based on morphologies and coloration (Chan et al. 2020). Specifically, females R. hosii are purplish with yellow lines protruding from their back, whereas females R. flavomaculata are light green with irregular yellow spots (Chan et al. 2016).

In life, adult females have a dark grey dorsal base while their underside is a brown-grey. The dorsal area is covered by an even, yellow, net-like pattern. Adult males have a brown or reddish-brown color on the dorsal area and a light grey underside (Chan et al. 2020).

Rentapia hosii exhibit sexual dimorphism in size and color with larger females, approximately 90 - 105 mm, and the smaller males, approximately 50 - 80 mm (Inger and Voris 2008). Females are brightly colored with yellow, green, or brown spottings, specifically purplish with yellow lines protruding from their back. Whereas the males are much duller and uniformly colored (Chan et al. 2016). The dorsal reticulations on R. hosii can differ depending on the amount and density. The coloration also differs from a scale of brown to dark grey and females can have major color changes in dorsal coloration when they are stressed (Chan et al. 2020).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Indonesia, Malaysia, Thailand

Malaysian region distribution from AmphibiaWeb's database: Peninsular Malaysia, Sabah, Sarawak

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (2 records).

Rentapia hosii was previously thought to be widely distributed throughout southern Thailand, Borneo, Sumatra, and Peninsular Malaysia (IUCN 2017). However, recent molecular analysis revealed that they are restricted to Borneo in the State of Sarawak, Malaysia and in the countries of Brunei Darussalam and Kalimantan. They may also be found in Sumatra, Indonesia but more analyses are needed to determine if the Sumatran populations are truly R. hosii, a population of R. flavomaculata, or a unique species (Chan et al. 2020).

Rentapia hosii can be found in dense vegetation, near lowland streams, in forests, and inland wetlands at elevations up to 700 meters (IUCN 2017).

Life History, Abundance, Activity, and Special Behaviors
Rentapia hosii is an arboreal species (IUCN 2017).

Male R. hosii vocalize for females from low foliage year round. During the breeding season, which occurs between late February and early March, males call to attract females for aquatic, external fertilization. Females descend from the tree tops to breed in nearby bodies of water. Males rely on axillary amplexus during breeding season. Once the pair decide to mate, they then search for a calm body of water or nearby stream. The female begins to lay long strings of ~4000 eggs per clutch in nearby forest streams. Each egg is approximately 1.2 mm in diameter (Chan et al. 2016).

Larva
Rentapia hosii larvae undergo indirect development, with an aquatic larval stage and a terrestrial juvenile stage (Inger and Voris 2008).

Trends and Threats
Rentapia hosii is listed as “Least Concern”. However they are still threatened by the development of rivers, clearing of forests and the sedimentation of streambeds. Residential and commercial developments are also considerable threats to this species. Their habitat is also threatened by the pollution of effluents from agricultural and forestry plants (IUCN 2017).

Relation to Humans
There is evidence to suggest that captive breeding of R. hosii is occurring, most likely for the pet trade (Choquette et al. 2020).

Possible reasons for amphibian decline

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

Comments
Maximum Likelihood and Bayesian Inference analyses on 16s mtDNA and CXCR4 and NCX1 nDNA, along with analyses on morphology and bioacoustics confirm that R. hosii is a unique species. The molecular analysis further indicate that R. hosii is sister to R. flavomaculata and together they form a clade that is sister to R. everetti (Chan et al. 2016, Chan et al. 2020).

Rentapia hosii was previously classified under the genus Pedostibes. However, Chan et al. (2016) determined that the species within Rentapia were more closely related to species of Phrynoidis than other Pedostibes. Indeed, the other species of Pedostibes formed a monophyletic group with Adenomus, Duttaphrynus, and Beduka (formerly known as Xanthophryne). This resulted in the creation of the genus Rentapia.

The genus Rentapia is named after Libau Rentap, an indigenous Iban warrior and hero in Malaysia, who incited a revolt against the English crown when the monarchy attempted to seize the land and enforce taxes upon the people of Sarawak. The Iban are the major indigenous ethnic group in Sarawak, a state in Malaysia on the island of Borneo (Chan et al. 2016).

Rentapia hosii is commonly referred to as the ‘brown tree toad’(IUCN 2017).

References

Boulenger, G. A. (1892). “An account of the reptiles and batrachians collected by Mr. C. Hose on Mt. Dulit, Borneo.” Proceedings of the Zoological Society of London, 69, 182-187.

Chan K.O., Grismer L.L., Zachariah A., Brown R.M., Abraham R.K. (2016). ''Polyphyly of Asian Tree Toads, Genus Pedostibes Günther, 1876 (Anura:Bufonidae), and the Description of a New Genus from Southeast Asia.'' PLoS One, 11(1), e0145903.

Chan, K. O., Abraham, R. K., Badli-Sham, B. H. (2020). “A revision of the Asian tree toad complex Rentapia hosii (Anura: Bunfonidae) with the description of a new species from Peninsular Malaysia.” The Raffles Bulletin of Zoology 68, 595-607. [link]

Choquette, R. E., Angulo, A., Bishop, P. J., Phan, C. T. B., Rowley, J. J. L. (2020). “The internet-based southeast Asia amphibian pet trade.” TRAFFIC Bulletin, 32, 2, 69-76. [link]

IUCN SSC Amphibian Specialist Group. 2017. “Rentapia hosii (amended version of 2014 assessment).” The IUCN Red List of Threatened Species 2017: e.T54862A114110853. https://dx.doi.org/10.2305/IUCN.UK.2017-1.RLTS.T54862A114110853.en. Downloaded on 17 February 2021.

Inger, R. F., Voris, H. K. (2008). “The biogeographical relations of the frogs and snakes of Sundaland.” Journal of Biogeography 28(7), 121-138. [link]

Species Account Citation: AmphibiaWeb 2023 Rentapia hosii: Rentap's Asian Tree Toad <https://amphibiaweb.org/species/385> University of California, Berkeley, CA, USA. Accessed Nov 23, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 23 Nov 2024.

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