African Elephant - Classification

Classification

• African bush elephant, Loxodonta africana
  • North African elephant, Loxodonta africana pharaoensis (extinct). Presumed subspecies north of the Sahara from the Atlas to Ethiopia.
• African forest elephant, Loxodonta cyclotis
• Loxodonta atlantica (fossil). Presumed ancestor of the modern African elephants
• Loxodonta exoptata (fossil). Presumed ancestor of L. atlantica
• ?Loxodonta adaurora (fossil). May belong in Mammuthus.

Bush and forest elephants were formerly considered subspecies of the same species Loxodonta africana. As described in the entry for the forest elephant in the third edition of Mammal Species of the World (MSW3), there is now morphological and genetic evidence they should be considered as separate species.

Much of the evidence cited in MSW3 is morphological. The African forest elephant has a longer and narrower mandible, rounder ears, a different number of toenails, straighter and downward tusks, and considerably smaller size. With regard to the number of toenails: the African bush elephant normally has four toenails on the front foot and three on the hind feet, the African forest elephant normally has five toenails on the front foot and four on the hind foot (like the Asian elephant), but hybrids between the two species commonly occur.

MSW3 lists the two forms as full species and does not list any subspecies in its entry for Loxodonta africana. However, this approach is not taken by the United Nations Environment Programme's World Conservation Monitoring Centre nor by the International Union for Conservation of Nature (IUCN), both of which list L. cyclotis as a synonym (not even a subspecies) of L.africana.

A consequence of the IUCN taking this view is that the IUCN Red List makes no independent assessment of the conservation status of the two forms of African elephant. It merely assesses the two forms taken together, as a unit, as vulnerable.

A study of nuclear DNA sequences published in 2010 indicated that the divergence date between forest and savanna elephants is 2.6–5.6 million years ago, which is virtually the same as the divergence date estimated between the Asian elephant and woolly mammoths (2.5–5.4 million years ago), strongly supporting their status as separate species. Forest elephants were found to have a high degree of genetic diversity, perhaps reflecting periodic fragmentation of their habitat during the climatic changes of the Pleistocene.