Rowley’s Litter Frog – Leptobrachella rowleyae – (Nguyen, Poyarkov, Le, Vo, Ninh, Duong, Murphy & Sang, 2018)

Science name: Leptobrachella rowleyae – (Nguyen, Poyarkov, Le, Vo, Ninh, Duong, Murphy & Sang, 2018)

Taxonomic:  Animalia>> Chordata>> Amphibia>> Anura >> Megophryidae >> rowleyae

Species status: Endemic ; IUCN status: CR (Critically Endangered Species)

Description: Size and Physical Characteristics: Leptobrachella rowleyae is a small-sized toad species within its genus. It has the typical shagreened skin with small tubercles and pustules that characterize many species of Leptobrachella. The species exhibits a robust body structure with a distinct tympanum and fine dorsal patterning.

Coloration in Life: The toad has a brownish dorsal coloration with darker markings that help it blend into the leaf litter. Its ventral side is lighter, with scattered pale spots. The eyes are a notable feature, with an orange-red coloration in the upper two-thirds of the iris, fading to silvery in the lower part.

Coloration in Preservative: In preservative, the toad’s vibrant colors fade, with the brownish and orange hues becoming more muted, though the general pattern remains discernible.

Distribution and habitat: Geographic Range: Leptobrachella rowleyae, known as Rowley’s Litter Toad, is endemic to Son Tra Nature Reserve, located in Da Nang, Vietnam. It has a highly restricted range, confined to elevations between 380 and 645 meters above sea level. The species has been documented within a single threat-defined location, with an estimated extent of occurrence (EOO) of only 19 km². This limited distribution makes it vulnerable to habitat disturbances.

Elevation: The species inhabits elevations ranging from 380 to 645 meters above sea level, primarily in small drainage basins within Son Tra Nature Reserve.

Area: Leptobrachella rowleyae is found in the remaining intact evergreen tropical forest of Son Tra Peninsula, which is isolated from the surrounding coastal area by human development. The species is highly dependent on the undisturbed forest ecosystem, thriving in moist forest floors and along small streams.

Habitat: The toad inhabits evergreen tropical forests and is closely associated with slowly flowing or seasonal streams. Males have been observed calling from holes in the ground or rocks, while females and tadpoles are often found in small pools connected to these streams. The species is forest-dependent and has not been observed in disturbed habitats.

Behaviour and ecology: Reproductive Biology: Leptobrachella rowleyae has a prolonged breeding season, extending from August to February. During this period, males are often found calling from small holes or near rocks along streams with slow currents. Females and tadpoles have been observed near the calling males. The species is presumed to breed in small, slow-flowing streams, with a free-swimming larval stage expected, similar to other Leptobrachella species.

Habitat Use: The species is forest-dependent and utilizes moist, undisturbed tropical forest areas. It is most commonly found on the forest floor, under leaf litter or in small holes, where it forages and breeds. The toad relies on intact forest ecosystems for its survival, and any disturbance to its habitat poses a significant threat to its population.

Conservation and status: IUCN Red List Category and Criteria: Leptobrachella rowleyae is currently listed as Critically Endangered under the IUCN Red List criteria B1ab(iii), primarily due to its restricted range, limited number of locations, and ongoing decline in habitat quality.

Population Trend: The population of Leptobrachella rowleyae is considered to be in decline, primarily driven by habitat loss and degradation caused by agricultural expansion and tourism development within Son Tra Nature Reserve.

Threats: The main threats to the species include habitat destruction from expanding agricultural activities, logging, and the growth of tourism infrastructure in the region. As the species is restricted to a single, small location, it is highly vulnerable to any environmental changes or disturbances.

Conservation Actions: Immediate conservation efforts should focus on protecting the remaining intact forest in Son Tra Nature Reserve. Measures to mitigate habitat degradation from agriculture and tourism are crucial. Further research is needed to better understand the species’ population size, distribution, and ecological requirements to develop effective conservation strategies.