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The earliest group of anthropoid
primates are the Oligopithecines known
from the Late Eocene which include Oligopithecus savagei, Catopithecus
browni, and Proteopithecus sylviae. Fossils of teeth are similar to those primates
which feed on insects and fruit. The large separation between the orbits (the
interorbital distance) is similar to that of prosimians which rely more on their sense of smell than the
smaller distance observed in all other anthropoids. Although the braincase of Catopithecus
was crushed, it appears that its brain size tobody
size ratio was smaller than modern anthropoids (Rasmussen, 1992). The
incomplete fossil of Algeripithecus
suggests that simians existed in
Catopithecus browni was an Upper Eocene primate which may be near the base of the anthropoid tree. Catopithecus was a small monkey outwardly similar to a marmoset. It possessed forward facing eyes, bifocal vision, a larger brain, and a monkey-like face (Kingdon, 2003). A number of specimens have been found including a virtually complete skeleton. Catopithecus possesses several prosimian characteristics but is thought to be near the base of the anthropoids. Its upper central incisors are larger than the lateral incisors as in anthropoid primates.
the lower central incisors are smaller than the lateral incisors (this
is an adapid characteristic; see illustration below); the incisors are
similar to those of anthropoids rather than prosimians (such as Arsinea) (Simons, 1995; Culotta, 1995) .
In Catopithecus, there was sexual dimorphism in the canine structure, a trait which is unknown in prosimians. Unlike most other Eocene primates, the roots of the central upper incisors fit closely like those of the anthropoids. In Catopithecus, there is the first appearance of anthropoid-like suture in the lower jaw. The postorbital closure of the eye region is equivalent to that of the anthropoid Aegyptopithecus and is not found in prosimians. This protects the eye and relieves the stress from chewing. The ectotympanic circles of the auditory opening are similar to Aegyptopithecus (and some prosimians). The foramen magnum and carotid foramen are similar to those found in higher primates. Catopithecus seems to be related to Proteopithecus and later Oligopithecus which are anthropoids.
It is possible that higher primates evolved in
NEW WORLD MONKEYS (platyrrhines)
|Among other features, New World monkeys still retain 3 premolars (see illustration below) as in the prosimians while the catarrhines (old world monkeys and apes) have only two.|
The platyrrine lineage diverged from that
of Old World monkeys and apes while
A middle Miocene fossil owl monkey, Aotus dindensis is
similar to modern members of the genus, as fossils Neosaimiri fieldsi and Stirtonia tatacoensis are similar to modern genera
and Alouatta. The
rate of change in some of the .
.A cebid monkey from the Early Miocene of Argentina, Killikaike, is a primitive member of the family Cebidae which possesses the enlarged forebrain characteristic of the group but lacks some of the changes of the facial bones (Tejedor, 2006).
| The fossil history of
|Below are photos of skull replicas
OLD WORLD MONKEYS AND APES (catarrhines)
| Parapithecus and Apidium were
fruit eating primates with a 2-1-3-3 tooth pattern of prosimians and
The early anthropoid Parapithecus was intermediate between prosimians and living anthropoids in its brain size and sensory structures (Bush, 2004)
|Oligopithecus savagei lived 35 million years ago. It possessed some prosimian characteristics in its teeth but it was the earliest primate to have the 2-1-2-3 tooth pattern that distinguishes the cusps on lower molars as in catarrhines (Delson, 1975).|
| Propliopithecus had
the 2-1-2-3 tooth pattern but
its incisors did not project forward as in modern catarrhines. Its premolars
were not one-cusped as in apes and its skeleton suggests a leaping lifestyle. Some species may have given rise to Aegyptopithecus. Some feel that Propliopithecus also gave rise to
Aegyptopithecus zeuxis lived 34-33 million years ago and is considered to be ancestral
Most Oligocene primates have tooth form and
microwear similar to modern fruit-eating primates. The teeth of Aegyptopithecus suggest that there was additional coarse material
in the diet.
Members of the subfamily Parapithecidae were
perhaps ancestral to
There are a variety of fossil old world monkeys such as those illustrated below.
following images are of three