 A 2016 genetic analysis showed the eastern green and black mambas are each others' closest relatives, their common ancestor diverging from a lineage that gave rise to Jameson's mamba ("Dendroaspis jamesoni") and the western green mamba ("Dendroaspis viridis").As well as being called the eastern green mamba, the species is also frequently known as the common green mamba, East African green mamba, white-mouthed mamba, or simply the green mamba.The eastern green mamba is a large snake, with a slightly compressed and very slender body with a medium to long tapering tail.