Cloaked moss frog – Theloderma palliatum – Rowley, Le, Hoang, Dau & Cao, 2011

Science name: Theloderma palliatum – Rowley, Le, Hoang, Dau & Cao, 2011

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

Species status: Endemic ; IUCN status: EN (Endangered Species)

Description:

Physical Characteristics:
Theloderma palliatum is a small frog, with males measuring 26.1–26.4 mm in snout-vent length (SVL). The frog has a pale to medium brown dorsum, with characteristic dark brown blotches along its body and dark brown lateral surfaces extending from snout to groin. The skin on its dorsum is weakly rugose, with minute pearly asperities scattered sparsely. It lacks vomerine teeth and has no webbing on its fingers, while the toes are partially webbed. One of its most distinguishing features is its bicolored iris, which is pale gold in the upper third and dark reddish-brown in the lower two-thirds.

The Cloaked Moss Frog’s slender body and bluntly truncate snout contribute to its distinct appearance. The smooth ventral surfaces, combined with bluish-white marbling on the chest and inguinal regions, further differentiate it from other species in the genus Theloderma.

Distribution and habitat:

Altitude:
Theloderma palliatum, commonly known as the Cloaked Moss Frog, inhabits montane regions at a specific elevation of approximately 1,625 meters above sea level (asl).

Range:
This species is currently only known from a single locality within Bidoup-Nui Ba National Park, located in Lac Duong District, Lam Dong Province, Vietnam. The species’ estimated extent of occurrence (EOO) is 1,443 km². Given the limited surveys in adjacent areas, it is possible that the species may also occur in similar habitats in northern Dac Lac Province and eastern Khanh Hoa Province. However, like many species in the Langbian Plateau, Theloderma palliatum may exhibit a high degree of endemism, remaining restricted to its current known range.

Habitat:
The Cloaked Moss Frog is found in montane evergreen forests, typically perched on trees or vegetation. Its arboreal nature and dependence on undisturbed montane forests suggest it thrives in areas with high humidity and intact forest canopies. Eggs of this species have been found in partially water-filled tree hollows, which play a crucial role in its reproductive cycle. Habitat disturbance from agriculture, aquaculture, and infrastructure development presents ongoing challenges to the survival of Theloderma palliatum.

Behaviour and ecology:

Lifestyle:
Theloderma palliatum is an arboreal species found in montane evergreen forests, typically observed perched on leaves or tree trunks about one meter above the ground. The species exhibits nocturnal activity, and its arboreal lifestyle is closely tied to the presence of dense, undisturbed forest canopies. Egg clutches of 4–5 individuals have been found in water-filled tree hollows, indicating that Theloderma palliatum may rely on these microhabitats for reproduction. Its small size and arboreal habits may make the species difficult to detect, potentially leading to its perceived rarity.

Reproduction:
Reproduction in Theloderma palliatum involves laying eggs in small water-filled hollows in fallen tree trunks. These water bodies provide a protected environment for the developing eggs and tadpoles. The species is known to exhibit clutch sizes of around 4–5 eggs. The reproductive cycle appears to be closely tied to the forest environment, with the arboreal nature of the frog playing a critical role in its breeding strategy.

Conservation and status:

IUCN Red List Category and Criteria:
Theloderma palliatum is listed as “Endangered” on the IUCN Red List under the criteria B1ab(iii), indicating its restricted distribution and the continuing decline in the quality and extent of its habitat. The species was last assessed in 2014, and its population is believed to be decreasing.

Threats:
The primary threat facing Theloderma palliatum is habitat degradation due to human activities, including agricultural expansion, aquaculture, infrastructure development, and forest product harvesting. These activities lead to the fragmentation and loss of the montane evergreen forests that the species depends on. The limited range and single known location of the species make it particularly vulnerable to these ongoing environmental pressures.

Conservation Actions:
Conservation efforts must focus on protecting the remaining montane evergreen forest in Bidoup-Nui Ba National Park. It is crucial to monitor the impact of human activities on the habitat of Theloderma palliatum, and further surveys should be conducted to assess the species’ presence in other areas of similar habitat. Expanding protected areas and implementing habitat restoration initiatives are key to ensuring the long-term survival of this endangered species.