Pine Narrow-Mouth Frog – Microhyla pineticola – Poyarkov, Vassilieva, Orlov, Galoyan, Tran, Le, Kretova & Geissler, 2014

Science name: Microhyla pineticola – Poyarkov, Vassilieva, Orlov, Galoyan, Tran, Le, Kretova & Geissler, 2014

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

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

Description:

Physical Characteristics:
Microhyla pineticola is a relatively small frog, with adult males ranging from 17.2 to 19.5 mm in snout-vent length and adult females slightly larger, between 18.0 and 23.0 mm. Its body is flattened, giving it a leaf-like appearance, and the head is triangular in shape, with approximately equal length and width. The snout is about one-third of the head length, and the nostrils are rounded, positioned closer to the tip of the snout than to the eyes. The canthus rostralis is sharp, and the eyes are protuberant, with diameters slightly shorter than the length of the snout. There is no visible pineal spot, and the tympanum is hidden, with a weak supratympanic fold running from the eye to the arm.

The limbs are slender, with webbing present between the toes, although the webbing is poorly developed. The fingers are long and slender, lacking webbing, with relative finger lengths I < II < IV < III. All fingers have discs with narrow dorsal grooves, and fingers II, III, and IV have an additional medial groove. The hind limbs are longer than the snout-vent length, with the tibiotarsal articulation extending between the nostril and snout tip when adpressed along the body. The toes are also slender, with poorly developed webbing, and the relative toe lengths are I < II < V < III < IV. Coloration: In life, the dorsum of Microhyla pineticola is typically pinkish brown with a distinct dark wood-grain pattern that runs across the head and down the sides of the body. A prominent dark brown, triangular interorbital bar is present, and darker markings can be seen on the back of the head and in the groin area. The appendages fade to white at their tips, and the ventrum is cream-white with faint light-brown marbling. In preserved specimens, the coloration fades, with red and pink tints becoming less distinct, and the yellowish sides turning more cream-colored. Males tend to have slightly different color patterns on their heads, sometimes displaying a large, butterfly-shaped brown pattern or a thin white stripe along the midline of the dorsum.

Distribution and habitat:

Altitude:
Microhyla pineticola is found at elevations ranging from 864 to 1,800 meters above sea level (asl). This montane species is primarily located in high-altitude regions, which include a mix of tropical and subtropical forests in central and southern Vietnam.

Range:
The known distribution of Microhyla pineticola is confined to the Lam Dong and Dak Lak Provinces in south-central Vietnam. However, its range may extend to similar habitats in the surrounding regions, such as parts of Khanh Hoa, Ninh Thuan, Binh Thuan, and Dak Nong Provinces. These regions share similar altitudinal and ecological characteristics, and further surveys could reveal the presence of this species in these areas. The estimated extent of occurrence (EOO) for M. pineticola is approximately 11,908 km², although its actual range may be larger. The species is currently known from only one threat-defined location.

Habitat:
Microhyla pineticola inhabits montane ecosystems, where it is associated with a variety of forest types, including mixed tropical forests and dry pine forests with a herbaceous understory. This terrestrial frog is often found in areas with seasonal or intermittent freshwater pools that serve as breeding sites. Although its reproductive behaviors have not been directly observed, advanced-stage tadpoles have been found in small, temporary rain pools in July, indicating that these habitats play an important role in its life cycle. Much of M. pineticola’s ecology and life history remain unknown, but it likely depends on intact forested environments for both shelter and breeding.

Behaviour and ecology:

Lifestyle:
Microhyla pineticola is a terrestrial species, typically found on the forest floor or near freshwater pools, particularly in montane regions. Like many other species in the genus, it likely hides among leaf litter or under logs during the day and becomes active at night, although specific behavioral observations are limited.

Reproduction:
Reproductive behavior in Microhyla pineticola has not been directly observed, but the discovery of advanced-stage tadpoles in temporary rain pools in mid-July suggests that breeding occurs in these ephemeral habitats. It is likely that the species deposits its eggs in small water bodies, with larvae developing in aquatic environments before undergoing metamorphosis.

Feeding:
As an insectivorous species, M. pineticola probably feeds on small invertebrates such as insects and arthropods, although specific dietary studies have not been conducted. Its slender body and long limbs may aid in capturing prey in dense undergrowth.

Conservation and status:

IUCN Red List Category and Criteria:
Microhyla pineticola is listed as “Vulnerable” under the IUCN Red List criteria B1ab(iii), reflecting its limited range, declining population, and the continuing loss and degradation of its habitat. The species was last assessed in 2015, and its population is thought to be decreasing due to habitat pressures.

Threats:
The primary threat to Microhyla pineticola is habitat loss, particularly from deforestation and agricultural expansion in its montane forest habitats. Pine forests, in particular, are vulnerable to logging and land conversion for agriculture, which threatens the species’ survival. Additionally, the species may be impacted by climate change, which could alter the availability of suitable montane habitats.

Conservation Actions:
There are currently no specific conservation measures in place for Microhyla pineticola. However, it occurs in regions that may overlap with protected areas in Vietnam, which could provide some level of habitat protection. Further research is needed to better understand the species’ distribution, population trends, and ecological needs. Conservation efforts should focus on protecting remaining forested areas and conducting surveys in adjacent provinces to better understand the full extent of its range.