Description
Rhacophorus pseudomalabaricus is a slender-bodied frog that has a male snout-vent range of 43.6 – 50.5 millimeters and one female specimen had a snout-vent length of 66.8 millimeters. It has a concave head and a rounded, laterally-oriented snout that projects slightly beyond its lower jaw. The length of its head is about the same as its width. The dorsolaterally oriented nostrils are closer to the snout than the eyes. The canthus rostralis is vertical. The loreal region is concave. The internarial distance is smaller than the interorbital distance. The large eyes have a diameter that is larger than the distance between the nostril and the eye. The eye has vertical pupils. The tympanum is indistinct, covered by skin, and smaller than the eye. A weak supratympanic fold is visible; it starts at the posterior corner of the eye, extends over the tympanum and ends at the base of the forelimbs (Vasudevan and Dutta 2000).

As an adaptation to its arboreal lifestyle, the frog has long forelimbs and hindlimbs. The forelimbs have dermal ornamentations and a flap of thick skin with a smooth margin extending laterally on the lower arm at the posterior margin. The hand has an indistinct palmar tubercle. The relative finger lengths are 1 < 2 < 4 < 3. There is one subarticular tubercle on fingers 1 and 2 and two on fingers 3 and 4. The fingers have expanded discs with circum-marginal grooves with the third finger having the largest disc. The fingers have webbing with a corrugated texture that covers two-thirds of the fingers. Specifically, the webbing extends from the distal subarticular tubercle of the first finger to the distal subarticular tubercle of the second finger. From the outer side of the second finger, the webbing extends from the base of the disc to the distal subarticular tubercle of the third finger. From the base of the disc on the outer third finger, the webbing extends to the disc of the fourth finger. Sexually reproductive males have nuptial pads located on the dorsolateral side of the first finger (Vasudevan and Dutta 2000).

The hind limbs have reduced dermal ornamentation in the form of coloration (see below) and a thick conical skin flap on the heel. When adpressed against the body, the tibio-tarsal articulation just reaches the nostril. When the legs are held at 90 degrees from the body, the heels overlap. The foot does not have an outer metatarsal tubercle but has an elongated inner metatarsal tubercle. Additionally, there is a ridge connecting the inner metarsal tubercle to the tibio-tarsal joint. The subarticular tubercles are round and distinct. The toes are fully webbed and have discs with circum-marginal grooves that are smaller than the finger discs. The 4th toe is the longest and has the largest disc. The order of toe length is 1 < 2 < 3 < 5 < 4 (Vasudevan and Dutta 2000). Even though the frogs are mainly arboreal, they also have specialized digging appendages on the aspects of the soles of their feet and fleshy spurs on their heels (Daniels 2005). Males have a single vocal (Harpalani et. al 2015, Vasudevan and Dutta 2000).

The frog’s dorsal skin and inner sides of the thigh are smooth. The skin on its ventrum, throat, and outer limbs are granular. The skin in the groin and around the cloaca has larger granules. It has a narrow waist (Vasudevan and Dutta 2000).

Rhacophorus pseudomalabaricus can be differentiated from all south Asian Rhacophorus species because of its leaf-venation-like patterning on the green body and limbs. More specifically, R. pseudomalabaricus is a species that is commonly confused with R. malabaricus. The two species can be distinguished by their locality and calls. Rhacophorus pseudomalabaricus resides in higher elevations than R. malabaricus, and its call is softer (Harpalani et. al 2005). The False Malabar gliding frog usually lives in rainforests in elevations above 1,000 meters, while the Malabar gliding frog lives in dry, secondary forests below 1,000 meters. They also differ in morphology: the False Malabar gliding frog has black lines on its back, while the Malabar gliding frog does not. No apparent geologic barrier exists to prevent reproduction between the species. This suggests the species are reproductively isolated from each other (Vasudevan and Dutta 2000).

In life, the head, dorsum and upper limbs of the frog are green with small, scattered white spots. Faint black lines will sometimes radiate from its back to the dorsum of its limbs. Metamorphs have more distinct stripes on their bodies, resembling the venation of leaves, which may help them with background matching for camouflage. The limbs of adults have a thick, green line that runs along their dorsal sides and half of the way through the fourth and fifth toe. The frog’s sides and the underside of its limbs are a yellow-cream color. Its fingers and toe tips are yellow-orange (Vasudevan and Dutta 2000). Their webbing can vary from light orange to a darker, red orange (Harpalani et al. 2015). When preserved, the scattered white spots on the dorsum turn purple and the yellow-orange color of the frog’s toes and webbing become a white or cream color (Vasudevan and Dutta 2000).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: India

View distribution map in BerkeleyMapper.

The Anaimalai flying frog has a small range in the Western Ghats of India. It is found in tropical, evergreen forests of the Anaimalai Hills, also known as the Elephant Hills, and the Cardamom Hills in the states of Tamil Nadu and Kerala. Rhacophorus pseudomalabaricus lives in altitudes between 955 - 1640 meters. Its distribution at higher elevation helps differentiate it from from the more widely distributed R. malabaricus, which it can be mistaken for. The species is most commonly seen among marshes and plantations (Harpalani et al. 2015). The only protected habitat R. pseudomalabaricus has is in the Indira Gandhi National Park in Tamil Nadu. This wildlife park experiences frequent human disturbance through ecotourism and local indigenous people activities (Vasudevan and Dutta 2000).

Life History, Abundance, Activity, and Special Behaviors
Rhacophorus pseudomalabaricus is a nocturnal, arboreal frog that is typically found in lower canopy and understory levels of tropical, moist, evergreen forests. The species may be found in marshes or small naturally occurring or artificial ponds (Biju et al. 2004, Harpalani et al. 2015).

Most mating occurs during the months of June to October, following the local monsoon season (Harpalani et. al 2015). Males have advertisement calls to attract mates that consist of a series of sounds, described as “trrr tik tik tik tik trrrr.” Each call lasts for an average of 2.5 seconds. Recorded using Raven sound analysis software, they attain peak amplitude of 1059 kU at the beginning and 2727 kU at the end. The interval between two consecutive calls ranges from 4.2 seconds to 14.1 seconds. Calls have been observed multiple times at night (Harpalani et al. 2015).

The frogs utilize axillary amplexus during the mating. Females make foam nests during amplexus by mixing excretions with her hindlimbs. The males grasp females with his feet positioned below her cloaca, potentially using his feet to transport sperm into the foam. After an hour of amplexus, and when ovipositioning is complete, the male moves away. The female remains to cover the nest with leaves using a “hugging” motion with her forelimbs. One female was observed spending four-and-a-half hours exhibiting this behavior (Vasudevan and Dutta 2000). Sometimes the nests are wrapped in leaves or other vegetation such as grass. Nests are built anywhere from ground level to 9 meters high near or above water. The frogs have also been observed utilizing invasive species of plants and artificial structures, such as water tanks, for nest sites (Harpalani et al. 2015).

Predators of adult frogs include carnivorous birds and primates, like the lion-tailed macaque. Primates have also been observed feeding on foam nests (Vasudevan and Dutta 2000).

Trends and Threats
The IUCN Redlist status for R. pseudomalabaricus is “Critically Endangered”. The population numbers of R. pseudomalabaricus is declining. The main threat against R. pseudomalabaricus is habitat destruction, which primarily includes the cultivation of land for use as plantations and extraction of timber for logging (Biju et al. 2004). However, Harpalani et al. (2015) found breeding populations of R. pseudomalabaricus in highly disturbed agricultural areas utilizing a variety of vegetation, including non-native species. The authors recommended exercising caution during habitat restoration efforts and downgrading the species IUCN Redlist threat status to “Endangered”.

Additional causes of decline include being run over by vehicles (Vasudevan and Dutta 2000, Kanagavel and Parvathy 2014, Harpalani et al. 2015) and being hunting or exterminated by local people because of perceived competition for cardamom and being a sign of bad luck (Kanagavel and Parvathy 2014, Harpalani et al. 2015).

Chytrid fungus is likely to occur in the Ghats where the frogs live, but it is currently unknown whether or not the disease affects R. pseudomalabaricus directly (Harpalani et. al 2015).

Relation to Humans
Rhacophorus pseudomalabaricus is treated as pest by local farmers. According to indigenous superstition, the Anaimalai flying frog is believed to be a bad omen, so it is not to be consumed and pregnant women are encouraged to avoid contact with it (Harpalani et al. 2015). Anecdotal evidence gathered from local communities suggests that R. pseudomalabaricus reside in cardamom plantations and are suspected to eat cardamom fruit. Although it is unknown whether or not the frogs actually do eat the fruit, they are publicly perceived as harmful to the commercial harvest of cardamom. In the Western Ghats, plantation owners therefore reward individuals who capture and kill frogs with monetary payment. This incentivization of hunting R. pseudomalabaricus on cardamom plantations threatens their persistence in these habitats (Kanagavel and Parvathy 2014, Harpalani et al. 2015).

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
Intentional mortality (over-harvesting, pet trade or collecting)

Comments
The species authority is: Vasudevan, K., Dutta, S.K. (2000). “A new species of Rhacophorus (Anura: Rhacophoridae) from the Western Ghats, India.” Hamadryad 25(1): 21-28.

Rhacophorus pseudomalabaricus is named after the frog R. malabaricus because the two species have similar appearances and are commonly confused. Rhacophorus pseudomalabaricus therefore received the name “false malabaricus.”

References

Biju, S.D., Dutta, S., Vasudevan, K., Srinivasulu, C, and Vijayakumar, S.P. (2004.) Rhacophorus pseudomalabaricus. The IUCN Red List of Threatened Species 2004: e.T59016A11869234. http://dx.doi.org/10.2305/IUCN.UK.2004.RLTS.T59016A11869234.en. Downloaded in February 2017

Harpalani, M., Parvathy, S., Kanagavel, A., Eluvathingal, L. M., Tapley, B (2015). ''.'' The Herpetological Bulletin , 133, 1-6.

Kanagavel, A., Parvathy, S. (2014). ''So in India, even Frogs like Spice in their food!'' FrogLog, 22, 18.

Vasudevan, K., Dutta, S.K. (2000). ''A new species of Rhacophorus (Anura: Rhacophoridae) from the Western Ghats, India.'' Hamadryad, 25(1), 21-28.

Species Account Citation: AmphibiaWeb 2018 Rhacophorus pseudomalabaricus: Anaimalai Flying Frog <https://amphibiaweb.org/species/6527> University of California, Berkeley, CA, USA. Accessed Nov 21, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 21 Nov 2024.

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