The following is an adapted summary of a blog post by Amaël Borzée:
Human activities, such as changing landscapes, have resulted in the sixth mass extinction, primarily affecting species with large sizes and limited geographic ranges. Since the 1500s, an estimated 900 to 130,000 species have gone extinct, including those not yet identified. Among animals, amphibians are the most threatened class, with habitat loss being a major cause of their decline. To effectively conserve these species, it is crucial to clearly understand their taxonomy, especially in regions like southern China, where many species still require formal descriptions or taxonomic revision. Conservation efforts should focus on known and understood species, as protection cannot be provided for species that remain undocumented.
While most Hynobius salamander species in China are expected to have been identified, taxonomic resolutions are still ongoing. There are currently six described species on the Chinese mainland and five on Taiwan island, all of which are terrestrial, partially fossorial, and undergo larval development in water bodies. However, one Hynobius salamander collected in Fujian in 1978 has not been observed since, suggesting possible local extinctions. To investigate the taxonomic status of this salamander, the authors conducted phylogenetic analyses and identified a new species, which they named Hynobius bambusicolus.
The analysis revealed a significant genetic divergence between H. bambusicolus and the 18 other known species. The candidate species displayed a higher average divergence rate, indicating it represents a distinct and deeply divergent clade within the Southern Chinese group of East Asian Hynobiids. All phylogenetic trees consistently identified the candidate species as a monophyletic group, and in some trees, it appeared as a sister species to H. amjiensis.
Using genetic data from COI gene fragments, the authors identified 55 haplotypes representing 16 Hynobius species across East Asia. The candidate species exhibited a high haplotype diversity and shared a close relationship with geographically related haplotypes of Southern Chinese Hynobius. Morphometric measurements revealed that the species was larger in size, possessed a low number of coastal grooves, and had a toe formula similar to other species in the region. The number of costal grooves proved an important characteristic for non-invasive species identification.
Based on a molecular analysis and morphological observations, Wang et al. (2023) described the new species as H. bambusicolus, commonly known as the Fujian Bamboo Salamander. This species was found in bamboo forests in Fujian province, China. Its name reflects its habitat and is derived from the Chinese name “虚竹小鲵” (pronounced: Xū Zhú Xiǎo Ní), inspired by a character from Jin Yong’s swordsman fiction.
The authors only encountered H. bambusicolus in Quxi village, Liancheng County, China. The species follows the typical reproductive pattern of Hynobius salamanders, with slow development of functional limbs during the larval stage. It can be identified by its unique combination of having ten or fewer costal grooves and a total length exceeding 180 mm. Juveniles display brown coloring with blue speckling, which fades as they mature into uniform dark chocolate-colored adults with light grey and blue speckling on the center.
Hynobius bambusicolus primarily breeds in shallow pools in bamboo forests above 1400 meters above sea level. They lay egg sacs containing 21 to 27 eggs in pools formed by tire tracks. Adult salamanders seek shelter under logs, stones, or dead leaves in wet soil and areas with high moisture content. They emit a short, low-frequency call, possibly as an alarm signal.
The description of H. bambusicolus is based on its distinct genetic origin, unique morphological characteristics, and separate distribution from other Hynobius species. Its geographic location facilitates its identification, as it does not overlap with other Hynobius species. It represents an ancient lineage that likely experienced distribution changes due to paleogeographic and climatic variations. The species’ habitat also includes other Caudata, which may lead to competition with other genera.
Hynobius bambusicolus has a highly limited distribution and a small population size, making it highly susceptible to extinction. It is adapted to sub-tropical bamboo forests but requires cold temperatures for spawning. Recent surveys confirmed that the species is known from only one location, with a few extremely small water bodies, potentially hosting a maximum of 20 breeding females. The population size is likely well below 200 breeding individuals, meeting the criteria for critically endangered status according to the IUCN Red List. Establishing an ex-situ population is recommended to prevent extinction due to climate instability and other risks.
To safeguard the new species, it is crucial for hobbyists to refrain from collecting or trading H. bambusicolus and to keep information about its location confidential. The primary threat to the species is habitat loss, particularly due to bamboo plantation and harvest, with climate change further exacerbating its vulnerability. To alleviate stress on the species, the use of herbicides and water pumping in the area should be minimized. Habitat restoration efforts, such as creating artificial ponds and rehabilitating old reservoirs, should be implemented to support population growth.
Reference:
Wang Z., Othman S. N., Qiu Z., Lu Y., Prasad V. K., Dong Y., Lu C-H. & Borzée A. (2023). An isolated and deeply divergent Hynobius species from Fujian, China. Animals. 13:1661. DOI: 10.3390/ani13101661.
