Quang Ninh Wart Frog – Limnonectes quangninhensis – Pham, Le, Nguyen, Ziegler, Wu & Nguyen, 2017

Science name: Limnonectes quangninhensis – Pham, Le, Nguyen, Ziegler, Wu & Nguyen, 2017

Taxonomic:  Animalia>> Chordata>> Amphibia>> Anura >> Dicroglossidae >> quangninhensis

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

Description:

Physical Characteristics: Limnonectes quangninhensis is distinguishable from other species within its genus by its body size and morphological traits. Males typically measure between 47.5 to 60.9 mm in snout-vent length (SVL), while females are slightly smaller, ranging from 42.3 to 51.1 mm. Males have a moderately enlarged head (head length to SVL ratio of 0.48), and the head is longer than it is wide. The species has vomerine teeth, invisible tympanum, and smooth skin on the dorsal surface of the head, body, and flanks. The tibia and foot are covered with small, dense tubercles, and toes are webbed to the posterior of the terminal phalanx.

Coloration and Appearance: In life, the species has light yellowish-brown markings on its dorsum. The throat and chest are white with brown markings, and the ventral surface of the abdomen is either fully white or white with additional brown markings.

Distribution and habitat:

Altitude: Limnonectes quangninhensis is found at elevations ranging from 5 to 229 meters above sea level. Its habitats are primarily situated in lowland areas.

Range: This species is currently known only from Quang Ninh Province, Vietnam, but it may have a broader distribution. Similar habitats and elevations in adjacent regions, such as Bac Giang and Lang Son provinces in Vietnam, and Guangxi Province in China, could also support its populations. Further surveys are needed to confirm this. The estimated extent of occurrence (EOO) for this species is currently between 4,355 and 25,984 km². The actual range could be under 20,000 km² once fully assessed.

Habitat: L. quangninhensis inhabits small, rocky streams in lowland secondary evergreen forests. These environments are characterized by moist subtropical or tropical forests and are essential for the species’ life cycle. It has been observed both in disturbed and undisturbed forests. However, the quality of its forest habitat is declining due to human activities, and the species’ ability to tolerate anthropogenic disturbances is uncertain.

Behaviour and ecology:

Lifestyle: L. quangninhensis is a semi-aquatic species, closely associated with rocky streams where it spends most of its time. It has been observed both in mainland and island forested areas. The species is thought to reproduce via aquatic larval development, though little is known about its reproductive biology. Gravid females have been observed in May, indicating that breeding likely occurs during the summer.

Feeding: While specific details on its diet are not available, L. quangninhensis likely preys on small invertebrates, similar to other members of the Limnonectes genus. Its aquatic and forested habitat provides ample access to such prey.

Reproduction: The species is presumed to reproduce by laying eggs in water, with larvae developing in streams. However, further research is needed to confirm these aspects of its reproductive biology. Gravid females have been observed during the month of May, suggesting a summer breeding season.

Conservation and status:

IUCN Red List Category and Criteria: Limnonectes quangninhensis is listed as Vulnerable under the IUCN Red List criteria B1ab(iii), meaning its population is at risk due to habitat decline. The assessment was last conducted in 2020.

Threats: The primary threat to L. quangninhensis is the degradation of its forest habitat. Deforestation and other human activities, including land conversion for agriculture and infrastructure development, contribute to the ongoing loss of suitable habitat for the species. These activities threaten both the quality and extent of its habitat, particularly in Quang Ninh Province, where human impact is significant.

Conservation Actions: Currently, no specific conservation measures are in place for L. quangninhensis. Protecting its forest habitat is crucial for its survival, especially in light of ongoing habitat loss. Establishing protected areas, enforcing laws against illegal deforestation, and conducting further research on its population size, distribution, and habitat requirements will be key to ensuring the species’ continued survival. Further field surveys are needed to determine its presence in nearby regions, as well as its potential tolerance to disturbed habitats.