海牛目Sirenia
----海牛科Trichechidae
--------海牛属Trichechu
------------亚马逊海牛Amazonian manatee (Trichechus inunguis)
------------西非海牛West African manatee (Trichechus senegalensis)
------------西印度海牛West Indian manatee (Trichechus manatus)
----儒艮科Dugongidae
--------儒艮属Dugong
------------儒艮Dugong (Dugong dugon)
--------无齿海牛属Hydrodamalis
------------大海牛Steller's sea cow (Hydrodamalis gigas)
长鼻目Proboscidea
----象科Elephantidae
--------象属Elephas
------------亚洲象Asian elephant (Elephas maximus)
--------非洲象属Loxodonta
------------非洲象African elephant (Loxodonta africana)
------------非洲森林象Forest elephant (Loxodonta cyclotis)