Cryptic Skink – Sphenomorphus cryptotis – Darevsky, Orlov & Cuc, 2004

Science name: Sphenomorphus cryptotis – Darevsky, Orlov & Cuc, 2004

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

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

Description: Physical Characteristics:

Size: It is a slender, medium-sized skink with well-adapted features for its arboreal and forested habitat.
Scales: The species has 6 supraoculars, 10-12 supraciliaries, and 7 supralabials. It also has 36-39 scale rows and nuchal scales present. Lamellae beneath the fourth toe range between 16-21, and its limbs are moderate, typically just overlapping or not at all when adpressed.
Ear Morphology: One of its most distinctive features is the absence of an external ear opening, with a slightly recessed auricular depression. This trait is highlighted by the species’ name.
Coloration and Appearance:
The tail is long and compressed laterally, which aids in balance and movement in its forested, semi-arboreal habitat.

Distribution and habitat: Elevation:
While specific elevation data is not provided in full, Sphenomorphus cryptotis has been recorded at elevations of 800-1000 meters above sea level, primarily in the Yen Tu mountain ridge and other forested regions of northern Vietnam.

Area:
This species is endemic to Vietnam, with confirmed populations in provinces like Lao Cai (Van Ban), Quang Ninh (Yen Tu Mountain), Nghe An (Quy Chau), Bac Giang, Dien Bien, and Ha Giang. It has also been found in Guangxi, China. Its range is primarily centered in subtropical and tropical forests of northern Vietnam, although its presence in China indicates a potentially broader distribution across southern Asia.

Habitat:
Sphenomorphus cryptotis inhabits evergreen secondary forests, preferring moist, dense environments near streams and rocky areas. It has been observed on hardwood, shrubs, and tree branches, and often resides above ground, ranging from 0.2 to 1.2 meters above the water in streams, indicating its semi-arboreal behavior.

Behaviour and ecology: Lifestyle:
Sphenomorphus cryptotis is a diurnal, semi-arboreal species, frequently observed on shrubs, hardwood branches, and near rocky streams. It is active during the day, foraging on the ground and in low vegetation, often near water. The skink appears to be well adapted to living in secondary forests, indicating some tolerance to habitat modification.

Reproduction:
Although specific reproductive behaviors are not well documented, the species is presumed to be oviparous like many skinks, laying eggs in secluded areas of its habitat.

Conservation and status: IUCN Red List Category and Criteria:
Sphenomorphus cryptotis is listed as Least Concern on the IUCN Red List, indicating that it is not currently facing significant risks of extinction. The most recent assessment was conducted in 2017.

Population Trend:
The population trend for Sphenomorphus cryptotis is currently unknown due to a lack of comprehensive data on its population size. However, its ability to live in secondary forests suggests some level of resilience.

Threats:
Potential threats to Sphenomorphus cryptotis include habitat loss and degradation due to deforestation, agricultural expansion, and other human activities. The species’ dependence on forested environments means that large-scale deforestation could negatively impact its population in the future.

Conservation Actions:
While there are no specific conservation measures targeting Sphenomorphus cryptotis, the protection of evergreen forest habitats in regions like Yen Tu Mountain and other known localities could indirectly benefit the species.

Etymology
The species name cryptotis is derived from the Greek words “cryptos” (meaning hidden or secretive) and “otis” (meaning ear), in reference to the species’ lack of an external ear opening.