No-thumb Pigmy Frog – Microhyla nanapollexa – Bain & Nguyen, 2004

Science name: Microhyla nanapollexa – Bain & Nguyen, 2004

Taxonomic:  Animalia>> Chordata>> Amphibia>> Anura >> Microhylidae >> nanapollexa

Species status: Endemic ; IUCN status: LC (Least Concern)

Description:

Physical Characteristics:

Microhyla nanapollexa is a small-sized, slender frog with a snout-vent length of approximately 16.63 mm. The species is characterized by the reduction of the first finger to a small, partially free nub, expanded disks on the remaining fingers and toes, and smooth skin. The dorsal surface is tan with charcoal gray markings, and the venter is lightly mottled brown.

Distinctive Features:

Finger I is reduced to a nub, unlike in many other congeners.
Expanded disks on fingers and toes with dorsal median longitudinal grooves forming scutes.
Webbing extends fully to the disks of toes I, V, and postaxial side of II.
Coloration: The species has a tan dorsum, charcoal gray head with distinctive medial markings, and lightly mottled ventral surfaces.

Distribution and habitat:

Altitude: Microhyla nanapollexa is found at an elevation of 1,480 meters above sea level (asl).

Range: This species is known from Ngoc Linh Mountain, Quang Nam Province, and Kon Plong District, Kon Tum Province in central Vietnam. It is possible that it also exists in southeastern Laos, as similar habitats and elevations are found there. A record from Phu Yen Province at lower elevations (350-400 meters asl) shows morphological differences from the Ngoc Linh population, suggesting the need for molecular confirmation.

Estimated Extent of Occurrence (EOO): 2,658 km², with a continuing decline.

Habitat: Microhyla nanapollexa inhabits montane broad-leaved evergreen forests, often in areas with mixed coniferous trees. Much of the forest in Vietnam’s Central Highlands, where this species occurs, has been converted to agricultural land. Habitat degradation continues, though it remains unclear how tolerant the species is to anthropogenic disturbances.

Behaviour and ecology:

Lifestyle: Microhyla nanapollexa is a terrestrial species found in montane forests. Little is known about its reproductive biology, but like some of its congeners, it is suspected to breed in tree hollows.

Reproduction: A gravid female has been observed in March, suggesting that the species breeds during this time.

Habitat Use: It occupies montane forests, particularly in less disturbed areas above 1,000 meters asl, though there is evidence of habitat loss and forest conversion in lower elevations.

Conservation and status:

IUCN Red List Category and Criteria: Microhyla nanapollexa has not yet been fully evaluated for the IUCN Red List, but it is likely to face habitat-related threats given the ongoing deforestation and agricultural expansion in the Central Highlands of Vietnam.

Threats: The main threat is habitat loss due to agricultural encroachment and deforestation. The conversion of montane forests to agricultural land in the Central Highlands poses a significant threat to the species.

Conservation Actions: There are currently no specific conservation measures for Microhyla nanapollexa, but further research is needed to confirm its full range and population status to better inform conservation efforts.