Abstract
The water toad (Bufo stejnegeri) is endemic to Northeastern Asia (South Korea, North Korea, and China) and has unique ecology for a toad by being semi-aquatic and breeding in lotic environments. We use a suite of phylogenetic analyses to understand the evolution of B. stejnegeri’s distinctive ecology and the impact of Pleistocene glacial cycles on the biodiversity of Northeast Asia. For the evolution of a semi-aquatic lifestyle, although B. stejnegeri is closely related to two other semi-aquatic Bufo species (B. torrenticola and B. andrewsi), ancestral state reconstruction analysis infers an independent evolution in all three species. Upon closer inspection, B. stejnegeri exhibits major differences in amplexus and egg-laying behaviour compared to the other two species, supporting independent evolution. Divergence dating analyses infer B. stejnegeri to have originated during the Late Miocene-Early Pliocene (4.3 Ma, 2.7–6.2 Ma). This species does not exhibit population differentiation with respect to mountain range, but shows a genetic pattern of southern richness and northern purity supporting a single refugium in Korea during Pleistocene glacial cycles. The Bayesian skyline plot supports this inference, inferring a population decline followed by expansion during the Pleistocene. Although not as species rich as the tropics, we hope this study helps spark interest in Northeast Asian biodiversity.
Highlights
The discipline of phylogenetic systematics, and its goal to understand character evolution and speciation, has shaped our understanding of the patterns and processes of evolution (Wiley and Lieberman, 2011)
B. stejnegeri is distributed in North Korea, we were unable to obtain samples from the region
All analyses of the individual locus datasets had lower resolution compared to the concatenated dataset, but B. stejnegeri always clustered with the same Bufo species listed above
Summary
The discipline of phylogenetic systematics, and its goal to understand character evolution and speciation, has shaped our understanding of the patterns and processes of evolution (Wiley and Lieberman, 2011). What begins as a simple study to understand the evolutionary genetics of a species can provide insight into broader evolutionary questions. Such is the case with our study of the water toad (Bufo stejnegeri). The water toad (B. stejnegeri) is endemic to Northeastern Asia (South Korea, North Korea, and China). As the common name implies, B. stejnegeri has unique ecology for a toad by being semiaquatic and breeding in lotic environments. Besides these basics, much of the biology of B. stejnegeri remains a mystery. Studying the genetics of B. stejnegeri provides a unique opportunity to understand the evolution of semi-aquatic toad ecology
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
