LABORATORY MANUAL FOR MAMMALOGY - Rowan

O. Primates
The Order Primates includes humans and the animals commonly referred to as apes and
monkeys. Several characters diagnose primates, including the presence of a petrosal bulla,
reduction of incisors to two upper and lower on each side, and the presence of a postorbital bar.
Primates show great diversity in diet and locomotion, but most are arboreal to at least some
degree. Unlike most mammals, most primates are diurnal rather than nocturnal, and most have
highly developed vision that is stereoscopic and usually color. Many primate species are social,
meaning that they habitually live in groups of multiple individuals. Primates are generally found
in tropical regions.
There are two major divisions of primates, the Strepsirhini and the Haplorhini.
Strepsirhines, sometimes referred to as prosimians, share many primitive features, but they also
share some derived features, such as the formation of a tooth comb from the lower incisors and
canines. This tooth comb is used for grooming. The term strepsirhine refers to "split nose,"
describing the primitive form of the nose in this group, which resembles that of a dog.
Haplorhines include tarsiers, monkeys, apes, and humans.
F. Lemuridae
Strepsirhines appear to have undergone a significant adaptive radiation on the large
oceanic island of Madagascar. The most diverse family of Malagasy (i.e., from Madagascar)
strepsirhines is the Lemuridae. Examine the lemur skull and note its primitive features in
comparison to a monkey skull. What is the dental formula of this lemur?
F. Tarsiidae
Tarsiers are small, nocturnal, insectivorous primates. They have enormous eyes and long
spindly legs specialized for leaping from branches. Examine the skull of a tarsier. Note the huge
orbits, and note the postorbital septum. This is the "wall" of bone separating the orbit from the
temporal fossa, a feature that tarsiers share with monkeys, apes, and humans. The teeth of
tarsiers include standard tribosphenic molars.
F. Callitrichidae and F. Cebidae
Haplorhines include the tarsiers and the Anthropoidea, which includes monkeys, apes,
and humans. Anthropoids are divided into two subgroups, the Platyrrhini and the Catarrhini.
Platyrrhines are the New World monkeys, whereas catarrhines are the Old World monkeys and
apes (including humans).
There are two families of platyrrhines, cebids and callitrichids, both found only in South
and Central America. Callitrichids include the marmosets and tamarins, small monkeys that are
generally insectivorous. Cebids include larger New World monkeys like howler monkeys and
spider monkeys. Cebids lack opposable thumbs, but many have prehensile tails. Both cebids
and callitrichids possess three premolars, but callitrichids have only two molars.
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