Huulien Ground Skink – Scincella apraefrontalis – Nguyen, Nguyen, Böhme & Ziegler, 2010

Science name: Scincella apraefrontalis – Nguyen, Nguyen, Böhme & Ziegler, 2010

Taxonomic:  Animalia>> Chordata>> Reptilia>> Squamata >> Scincidae >> apraefrontalis

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

Description: 

Physical Characteristics:

Size: Small skink, measuring 36.1 mm in snout-vent length (SVL).
Scales: The species lacks supranasals and prefrontals. It has two or three pairs of nuchals, six supralabials, and five infralabials. Notably, the nasal and first supralabial are fused. Its midbody scales are arranged in 18 rows.
External Features: The skink has no external ear openings, and its lower eyelid features an undivided opaque window, a trait seen in certain Scincella species.
Coloration and Appearance:
The dorsum and tail base are bronze-brown, with some indistinct darker spots on the anterior part of each scale. The laterals are paler and feature three or four longitudinal dark brown stripes, creating a distinct appearance.

Distribution and habitat:

Elevation:
The type locality of Scincella apraefrontalis, commonly known as the Huulien Ground Skink, is situated at an elevation of approximately 200 meters above sea level in the Huu Lien Nature Reserve, Huu Lung District, Lang Son Province, Vietnam.

Area:
This species is currently known only from the Huu Lien Nature Reserve in northern Vietnam, though there is potential for its range to extend into other areas within Lang Son and Nghe An provinces. Its natural habitat consists of secondary limestone forests, a common type of forest in this region.

Habitat:
The Huulien Ground Skink has been observed in secondary forest habitats, where it was found in leaf litter on the forest floor. While Scincella species are often adaptable to secondary forests, they are known to be intolerant of deforested areas, suggesting that this species may require intact forest ecosystems to thrive. The forest type is characterized by moist lowland subtropical/tropical conditions, offering suitable ground cover and humidity for its survival.

Behaviour and ecology: 

Lifestyle:
Scincella apraefrontalis is diurnal, and it was found active during the daytime among leaf litter in its forest habitat. Like other ground-dwelling skinks, it likely forages for small invertebrates and uses its environment for cover and camouflage. Its short limbs, pentadactyl feet, and subdigital lamellae (with eight lamellae on the fourth toe) help it move efficiently through the leaf litter on the forest floor.

Reproduction:
The species is oviparous, although specific reproductive behaviors, such as clutch size and breeding season, have not been well documented.

Conservation and status: 

IUCN Red List Category and Criteria:
Scincella apraefrontalis is currently listed as Data Deficient on the IUCN Red List due to a lack of sufficient data on its population size, distribution, and ecological requirements. The most recent assessment was conducted in 2017.

Population Trend:
The population trend of Scincella apraefrontalis is unknown. Since only a single specimen has been recorded, there is no available information on population stability or decline.

Threats:
The primary potential threat to Scincella apraefrontalis is habitat loss due to deforestation and the degradation of limestone forests. Although the species seems tolerant of secondary forest habitats, continued forest fragmentation and deforestation could pose significant risks to its survival.

Conservation Actions:
Currently, there are no specific conservation actions in place for Scincella apraefrontalis. However, the Huu Lien Nature Reserve, where it was first found, may offer some degree of habitat protection. Further research is needed to assess its population size, distribution, and ecological requirements to inform future conservation strategies.

Etymology
The species name apraefrontalis is derived from Latin, meaning “without prefrontals,” in reference to the species’ lack of prefrontal scales, a distinctive characteristic of this skink.