East Siberian lemming
It was formerly thought conspecific with the West Siberian lemming (L. sibiricus), which replaces it west of the Verkhoyansk Range, with both species being previously classified together as the Siberian brown lemming.More recent genetic studies found both the eastern L. sibiricus and the northern L. amurensis together represent a distinct species.[3] There are several disjunct populations; one is found from the Verkhoyansk Range east to the Kolyma River, including the New Siberian Islands; it is largely replaced by the Beringian lemming (L. nigripes) east of this region.[1] Finally, an isolated population is present on Wrangel Island.This population was previously included as a subspecies of L. sibiricus by Jarrell and Fredga in 1993, while Chernyavskii (also in 1993) regarded it as a separate species, L. portenkoi.