Evolution And History

Primate Taxonomy 59

gorillas, they differ as to whether they use the term hom-

inid or hominin to describe the taxonomic grouping of

humans and their ancestors. Museum displays and much

of the popular press tend to retain the old term hominid,

emphasizing the visible differences between humans and

the other African apes. Scientists and publications using

hominin (such as National Geographic) are emphasiz-

ing the importance of genetics in establishing relation-

ships among species. These word choices are more than

and apes.^1 The taxonomic scheme reflecting this genetic
relationship places lemurs and lorises in the suborder
Strepsirhini (from the Greek for “turned nose”). In turn,
the suborder Haplorhini (Greek for “simple nose”) con-
tains the tarsiers, monkeys, and apes. Tarsiers are sepa-
rated from monkeys and apes at the infraorder level in this
taxonomic scheme. Although this classificatory scheme
accurately reflects genetic relationships, comparisons
between grades, or general levels of organization, in the
older prosimian and anthropoid classification make more
sense when examining morphology and lifeways.
Using the older taxonomic scheme, the anthropoid
suborder is further divided into two infraorders: the
Platyrrhini, or New World monkeys, and the Catarrhini,
consisting of the superfamilies Cercopithecoidea (Old
World monkeys) and Hominoidea (apes). Although the
terms New World and Old World reflect a Eurocentric vi-
sion of history (whereby the Americas were considered
new only to European explorers and not to the indigenous
people already living there), these terms have evolutionary
and geologic relevance with respect to primates, as we will
see in Chapter 6. Old World monkeys and apes, including
humans, have a 40-million-year shared evolutionary his-
tory in Africa distinct from the course taken by anthropoid
primates in the tropical Americas. “Old World” in this con-
text represents the evolutionary origins of anthropoid pri-
mates rather than a political or historical focus on Europe.
In terms of human evolution, however, most taxo-
nomic controversy derives from relationships established
by the molecular evidence among the hominoids. Humans
are placed in the hominoid or ape superfamily—with
gibbons, siamangs, orangutans, gorillas, chimpanzees, and
bonobos—due to physical similarities such as broad shoul-
ders, absent tail, and long arms. Human characteristics
such as bipedalism (walking on two legs) and culture led
scientists to think that all the other apes were more closely
related to one another than any of them were to humans.
Thus humans and their ancestors were classified in the
hominid family to distinguish them from the other apes.
Advances in molecular analysis of blood proteins and
DNA later demonstrated that humans are more closely re-
lated to African apes (chimps, bonobos, and gorillas) than
we are to orangutans and the smaller apes (siamangs and
gibbons). Some scientists then proposed that African apes
should be included in the hominid family, with humans
and their ancestors distinguished from the other African
hominoids at the taxonomic level of subfamily, as homi-
nins (Figure 3.3).
Although all scientists today agree about the close re-
lationship among humans, chimpanzees, bonobos, and

Strepsirhini In the alternate primate taxonomy, the suborder

that includes the lemurs and lorises without the tarsiers.

Haplorhini In the alternate primate taxonomy, the suborder

that includes tarsiers, monkeys, apes, and humans.

Platyrrhini A primate infraorder that includes New World

monkeys.

Catarrhini A primate infraorder that includes Old World

monkeys, apes, and humans.

hominoid The taxonomic division superfamily within the

Old World primates that includes gibbons, siamangs, orang-

utans, gorillas, chimpanzees, bonobos, and humans.

hominid African hominoid family that includes humans and

their ancestors. Some scientists, recognizing the close relationship

of humans, chimps, bonobos, and gorillas, use the term hominid

to refer to all African hominoids. They then divide the hominid

family into two subfamilies: the Paninae (chimps, bonobos, and

gorillas) and the Homininae (humans and their ancestors).

hominin The taxonomic subfamily or tribe within the pri-

mates that includes humans and our ancestors.

Lemurs and lorises

Tarsiers

New World monkeys

Old World monkeys

Siamangs

Gibbons

Orangutans

Gorillas

Bonobos

Chimpanzees

Humans

Common

ancestor

Figure 3.3 Based on molecular evidence, a relationship can

be established among various primate groups. This evidence

shows that tarsiers are more closely related to monkeys

and apes than to the lemurs and lorises that they resemble

physically. Present thinking is that the split between the

human and African ape lines took place between 5 and

8 million years ago.

(^1) Goodman, M., et al. (1994). Molecular evidence on primate phylogeny
from DNA sequences. American Journal of Physical Anthropology 94, 7.