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March 2006

(Click here for PDF version of this page)

With growing molecular knowledge and other studies, evolutionary relationships of the hominoids has become clearer in recent years. The studies that are most pertinent to some of the ENSI materials involve recognizing the especially close genetic and evolutionary relationships that exist between the three African apes (gorilla, chimpanzee and bonobo) and humans. The taxonomic consequence of these studies has been to revise some taxonomic groupings.

The Superfamily Hominoidea (hominoids) is still the collective name for all of the apes and humans with three taxonomic families included: gibbons and siamangs (the "lesser"apes) are the Hylobatidae, the orangutan (genus Pongo) is exclusively in the Pongidae, and the African apes (gorillas, chimpanzees and bonobos) plus humans are placed in the Hominidae (hominids). In turn, the Hominidae typically has three subfamilies: Gorillinae (gorillas) , Paninae (the 2 species of Pan) and the Homininae (hominins: humans, living and extinct).

In outline format:

The confusing aspect of this taxonomic revision, of course, involves the revised use of the term "hominid." In the past, the term "hominid" was used to refer only to humans and all their extinct bipedal predecessors and cousins distinct from any apes. Now "hominid" is to be used to refer to humans and all of the African apes together. The term "hominin" is now the common term to refer to those forms previously referred to as hominids.

Confusing, isn't it? Well, cheer up! It could be worse. There are some biologists who maintain that the trichotomy of three subfamilies is inconsistent with the dichotomous structure of cladistic analysis, and suggest various ways that this should be modified to reflect "true" divergence points based on the best molecular data, requiring further revisions in nomenclature. There are also several geneticists who argue that even this taxonomic revision does not sufficiently reflect how similar humans, chimpanzees and bonobos really are. These scientists assert that it is justifiable on genetic grounds to place all three of these species (Homo sapiens, Pan troglodytes and Pan paniscus) in the same genus, Homo! (Click here for details.) Are you really ready to teach that? We didn't think so, either.

Martin K. Nickels, Ph.D.
Professor Emeritus of Anthropology
ENSI Co-Director

Click HERE for further discussion.

Every effort is being made to update lessons and other materials on the ENSI site to reflect the "compromise" taxonomy outlined in detail above. If you find any item on the site where this apparently has not been done, please let the webmaster know.
Larry Flammer, ENSI webmaster, March 2006