Elephants from the tropical forests of Africa are morphologically distinct from savannah or bush elephants. Dart-biopsy samples from 195 free-ranging African elephants in 21 populations were examined for DNA sequence variation in four nuclear genes (1732 base pairs). Phylogenetic distinctions between African forest elephant and savannah elephant populations corresponded to 58% of the difference in the same genes between elephant genera Loxodonta (African) and Elephas (Asian). Large genetic distance, multiple genetically fixed nucleotide site differences, morphological and habitat distinctions, and extremely limited hybridization of gene flow between forest and savannah elephants support the recognition and conservation management of two African species: Loxodonta africana and Loxodonta cyclotis.
Roca, Alfred L.; Nicholas Georgiadis; Jill Pecon-Slattery; and Stephen J. O'Brien. 2001. "Genetic Evidence for Two Species of Elephant in Africa." Science 293, (5534): 1473-1477. https://nsuworks.nova.edu/cnso_bio_facarticles/628