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Prosimians tend to have thinner enamel than anthropoids. The exception is Daubentonia which has very thick enamel on the
M2. The strepsirhines have reduced upper incisors and tooth combs. The tooth comb origin has been debated. Hypotheses for
the origin of the tooth comb range from grooming purposes to feeding on gum and bark. Prosimian diets consist of a variety
of foodstuffs including: insects, seeds, fruits, shoots, leaves, birds' eggs, and young animals. Prosimians have little canine
sexual dimorphism.
Superfamily Lemuroidea: The Lemuroidea live exclusively on the island Madagascar. They posses tooth combs and upper incisors
that are small (I1 and I2 are close together). This leaves a diastema between those two incisors. The upper canines are
long and distally curved. There is a small diastema between the upper canines and the upper P2. The premolars increase in
size mesiodistally, and the second premolars are canine like in morphology. The third premolars are somewhat caniniforms
due to its unicuspid shape. The fourth premolar is broadened and many genera have a crest connecting the protocone and paracone.
Hapalemurs have molarized P4s in both the upper and lower jaws. In most species the lingual cingulum is prominent and some
have a developed hypocone. The lower molars have a trigonid and talonid The paraconid is absent, and the hypoconulid's development
varies among species. The protocristid connects the protoconid and metaconid.
Superfamily Lorisoidea: The superfamily lorisoidea consists of two families Galagidae and Lorisidae.
Galagidae: Their diet consists of insects, fruits, leaves, gum, and birds' eggs. The upper incisors are separated by
a diastema. They are also thin and tall. The lower incisors help to form the tooth comb complex with the lower canines.
The upper canine is tall and there is a very small lingual cingulum on the base. The upper P2s have a paracone. The upper
P3s may have a protocone. The upper and lower P4s are molariform, and the uppers have a large paracone and small protocone.
The lower P2 is conical or canine-like. It also contains a lingual cingulid. The lower P4 s have four cusps, occlusal cristids,
and broad talonid basin. The large protoconid and smaller metaconid are set close together. The upper and lower M1s and
M2s have four cusps and M3s have no hypocone. The trigon basin is broad with crista obliqua between the protocone and metacone.
The lower M3s have a hypoconulid. The talonid basin becomes narrower from M1 to M3 in the lower jaw.
Lorisidae: Diet is similar to the Galagidae. The upper incisors are small, and there is a diastema between the I1s.
The lower incisors and canines help form the tooth comb, but the incisors do not stick out as much as lemurs. The large upper
canines have a lingual cingula. A lingual cingulum is present on the upper pre molars. The upper and lower P2 is canine
like in morphology. The lower P2 has a lingual cingulid. The P3 has a protocone. The upper M1 and M2 has 4 cusps, and M3
is the smallest molar. Crista obliqa and occlusal cristae are present on the upper M1s and M2s. The lower molars all have
four cusps, and the M3 has an additional hypocone.
Superfamily Tarsioidea: Tarsiers are found in Southeast Asia. They eat insects and small vertebrates. Tarsiers have
three premolars and one lower incisors. Tarsiers, unlike other prosimians, do not have a tooth comb. The upper incisors
are vertical, I1 is larger than I2, and there is no diastema separating the incisors. The upper canine is sharp and the lower
is larger. The lower canine has a cingulid at the base. The upper P2 is caniniform and the P4 has a complex cingulum. The
lower premolars are similar to each other and have a protoconid. The upper molars are tribosphenic. A crsita oblique and
buccal cingula are present on all upper molars. The lower molars are also tribosphenic. There is no lingual cingulid.
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