New lab paper on the trade of Brown Frogs (Rana sp.) in northeast Asia, including the delineation of cryptic species, and morphological tools for species identification to act against the trade of mis-identified individuals.
The trade of amphibians increases the risk of invasions across the world, and northeast Asia. To understand the trade in the area, we developed an accurate species assignment and workflow guiding a broad-scale species identification and resolving the trade pathways. We tested our workflow on unidentified cryptic brown frogs imported into the Republic of Korea.
The workflow combined morphometry, phylogenetic trait, species delimitation modelling and phylogeography, and successfully identified three non-native species imported in Korea: Rana chensinensis, Rana amurensis and Rana kukunoris out of 171 specimens bought from the trade.
Using a machine-learning approach with Bayes Factor Delimitation method to evaluate the taxonomy models from four commonly used species delimitation tools (BLAST, ABGD, sGMYC and bPTP), and isolated 12 operational taxonomic units (OTUs) from the 171 individuals. We then combined the information from the 12 OTUs and combined it into a 16S phylogeny including traded and control specimens (n = 230).
The model-based OTUs and phylogeny revealed the widespread and likely wild-harvested origins of traded Rana individuals, cycled through farm in China to be integrated in the legal trade. Apart from the genetic, our morphometry also indicates extremely high phenotype crypticity between the endemic Korean species, especially R. huanrenensis and those brown frogs from the trade.
However, the trait evolution results also highlight a pattern of independent evolution of toe webbings in Rana for the last 12.0 Mya, most likely a useful key-trait for Rana species identification across northeast Asian. With the workflow for broad-scale species identification developed herein, we urge the development of trade monitoring and legislation on Rana species in northeast Asia.
Othman S. N., Shin Y., Kim H.-T., Chuang M.-F., Bae Y., Hoti J., Zhang Y., Jang Y. & Borzée A. (2022).Evaluating the efficiency of popular species identification analytical methods, and integrative workflow using morphometry and barcoding bioinformatics for taxonomy and origin of traded cryptic brown frogs.Global Ecology and Conservation. 38:e02253. DOI: 10.1016/j.gecco.2022.e02253