Marbled-backed Flying Frog – Rhacophorus marmoridorsum – Orlov, 2008

Science name: Rhacophorus marmoridorsum – Orlov, 2008

Taxonomic:  Animalia>> Chordata>> Amphibia>> Anura >> Rhacophoridae >> marmoridorsum

Species status: Endemic ; IUCN status: VU (Vunerable)

Description:

Physical Characteristics:
Rhacophorus marmoridorsum is a medium-sized frog with a robust body, dorsoventrally flattened, and adapted for an arboreal lifestyle. Its snout-vent length (SVL) can reach up to 50 mm. The species’ dorsal color is typically flesh-colored or cream, with distinctive markings along the center of the back. The skin on the back is smooth, while the ventral side is cream-colored with some rough texture. Its fingers and toes are fully webbed, which, combined with enlarged adhesive discs at the tips of its digits, aids in climbing and leaping between trees. This species also has vomerine teeth, a common characteristic among tree frogs in its genus.

Distribution and habitat:

Altitude:
Rhacophorus marmoridorsum is found at elevations around 1,100 meters above sea level (asl).

Range:
This species is endemic to Vietnam and is currently known from only one locality in the Kon Cha Rang area, An Khe District, Gia Lai Province. It is believed that the species might inhabit adjacent areas in Quang Ngai, Binh Dinh, and Gia Lai Provinces, as the habitat in these regions is similar to the species’ known environment. However, further surveys are needed to confirm its presence in these areas. The estimated extent of occurrence (EOO) for the species is 6,927 km², though this estimate covers only two threat-defined locations, suggesting a limited distribution.

Habitat:
Rhacophorus marmoridorsum occupies steep, rocky terrain within valleys of cascading streams surrounded by broad-leaved evergreen forests. This frog thrives in moist montane environments where permanent streams and creeks provide essential aquatic habitats for reproduction. Much of its reproductive biology remains unknown, but it is likely that, similar to other species in the Rhacophorus genus, it has a free-living aquatic larval stage. The habitat throughout its known range is under pressure from deforestation, particularly for agriculture, which is degrading the quality and extent of its forested environment.

Behaviour and ecology:

Lifestyle:
This species inhabits the forest canopy but spends considerable time near streams and waterfalls in montane forests. It is presumed to be nocturnal and, like many other tree frogs, probably forages on insects and other small invertebrates found in its environment. During the breeding season, males likely call to attract females, although little is known about the specifics of its mating behavior. The species’ reproductive strategy is expected to involve laying eggs in foam nests overhanging water, a common trait in the Rhacophorus genus, where the larvae, or tadpoles, drop into the water after hatching.

Reproduction:
The reproductive biology of Rhacophorus marmoridorsum is not well studied, but it is presumed to have a similar breeding strategy to other Rhacophorus species. This likely includes the creation of foam nests for egg deposition, with tadpoles eventually hatching and dropping into the streams or pools below to complete their development in the aquatic environment.

Conservation and status:

IUCN Red List Category and Criteria:
Rhacophorus marmoridorsum is listed as “Vulnerable” under the IUCN Red List Category B1ab(iii). This assessment was made in 2015, and the species continues to face significant threats from habitat degradation.

Threats:
The primary threat to Rhacophorus marmoridorsum is habitat loss, particularly due to deforestation for agricultural expansion and infrastructure development. The species’ limited known range makes it especially vulnerable to such disturbances, as any significant reduction in habitat could result in a sharp decline in population. The degradation of forests, particularly the loss of permanent streams and clean water sources, poses a direct threat to its breeding habitats, as the species is believed to be dependent on such environments for reproduction.

Conservation Actions:
Conservation efforts for Rhacophorus marmoridorsum should focus on habitat preservation. The species is currently found within a protected area, but further expansion of protected habitats and stricter enforcement of forest protection laws are crucial to prevent further habitat loss. Surveys to identify additional populations in adjacent areas and to better understand the species’ range, population dynamics, and ecology are also necessary. Additionally, research into its reproductive behavior, habitat needs, and potential adaptability to changing environments would inform more effective conservation strategies.