Behind the mountains and over the sea: the Changbai Mountain Range provided Rana coreana with a Chinese residence permit all along.

Abstract

The Changbai Mountain Range is generally perceived as a barrier to amphibian distribution, but it might not be playing this role anymore. Rana coreana was first described as a Korean endemic species, split from Rana amurensis, which ranges at more northern latitude. The species was then found on the Shandong peninsula in China, where it was first described as Rana kunyuensis, before being synonymised with R. coreana. So far, the contact zone with R. amurensis was expected to be in the vicinity of Pyongyang in DPR Korea, west of the Baekdu Mountain Range. However, the species is known from a population further north, and during surveys in Dalian in Liaoning Province, China, we found R. coreana on the southern slopes of the Laoling Mountain Range facing the Yellow Sea. Our phylogenetic analyses based on mitochondrial ribosomal markers showed the individual to cluster with R. coreana samples from the Korean Peninsula. In addition, our ecological niche models showed the presence of suitable habitats outside of the known range of the species, deserving further investigation. The habitat of the species at this new locality is similar to the one known in the three range nations, and highlights the need for more surveys in northeast China as the barrier formed by the Changbai Range is more porous than originally expected.