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Description

A selection of extinct members of cercopithecid primates, to scale.

Amongst all the primates, macaques would meet most people's criteria for a 'typical' monkey. They are the most commonly kept primate in zoos, a common laboratory subject and many live in close proximity to urban areas. Macaques are just one part of a diverse cercopithecid family, split into two subfamilies - the cercopithecines and the previously covered colobines (see Monkey business - Cercopithecids 1 ). Cercopithecines are characterised by cheek pouches, and split into two tribes: cercopithecines (guenons) and papionines (baboons, mangabeys, geladas, macaques). The earliest cercopithecine fossils are known from the Late Miocene.

Guenons are rarely found in the fossil record, a reflection of most being forest-dwellers (not the best location for fossil preservation), although several fossils have been found in the drier environments of the Arabian peninsula and Kenya (Nanopithecus). The fossil record for the papioines is far better known. Earliest forms, such as the Late Miocene Pliopapio were generalists being equally active on the ground and in the trees. While some later species, such as Parapapio were agile in trees and on the ground, others were restricted to predominantly terrestrial lifestyles due to their size. Some species of baboons from the Plio-Pleistocene were massive, with the males of Dinopithecus (a true baboon) and Theropithecus (a gelada) estimated to get over 40 kgs (even 77 kgs has been suggested; compare that to the heaviest living species - male mandrills can reach 32 kgs). Baboons and geladas evolved in different parts of Africa (southern and eastern, respectively), and it was only during the last glacial period that geladas have been confined to the Ethiopian highlands. Baboons took advantage of the vacuum and now range across most of Africa (apart from rainforest and deserts).

It was only the macaques and their closest relatives which have properly ventured and diversified outside Africa (one species of Theropithecus made it as far east as India). An early form was the large terrestrial Paradolichopithecus, which is notable for several interesting features: it had an elongated muzzle like a baboon, and the ankle joints resembled those of Australopithecus suggesting that it potentially spent time walking bipedally. Typical living macaques are mostly confined to Asia, however the Barbary macaque Macaca sylvanus of North Africa is a notable outlier. During the Pliocene and Pleistocene macaques also ranged further north into Europe. One isolated form, M. majori was left stranded on the Mediterranean island of Sardinia during the Early Pleistocene, where it underwent shrinking in body size over time.

Description

A selection of extinct members of cercopithecid primates, to scale.

Amongst all the primates, macaques would meet most people's criteria for a 'typical' monkey. They are the most commonly kept primate in zoos, a common laboratory subject and many live in close proximity to urban areas. Macaques are just one part of a diverse cercopithecid family, split into two subfamilies - the cercopithecines and the previously covered colobines (see Monkey business - Cercopithecids 1 ). Cercopithecines are characterised by cheek pouches, and split into two tribes: cercopithecines (guenons) and papionines (baboons, mangabeys, geladas, macaques). The earliest cercopithecine fossils are known from the Late Miocene.

Guenons are rarely found in the fossil record, a reflection of most being forest-dwellers (not the best location for fossil preservation), although several fossils have been found in the drier environments of the Arabian peninsula and Kenya (Nanopithecus). The fossil record for the papioines is far better known. Earliest forms, such as the Late Miocene Pliopapio were generalists being equally active on the ground and in the trees. While some later species, such as Parapapio were agile in trees and on the ground, others were restricted to predominantly terrestrial lifestyles due to their size. Some species of baboons from the Plio-Pleistocene were massive, with the males of Dinopithecus (a true baboon) and Theropithecus (a gelada) estimated to get over 40 kgs (even 77 kgs has been suggested; compare that to the heaviest living species - male mandrills can reach 32 kgs). Baboons and geladas evolved in different parts of Africa (southern and eastern, respectively), and it was only during the last glacial period that geladas have been confined to the Ethiopian highlands. Baboons took advantage of the vacuum and now range across most of Africa (apart from rainforest and deserts).

It was only the macaques and their closest relatives which have properly ventured and diversified outside Africa (one species of Theropithecus made it as far east as India). An early form was the large terrestrial Paradolichopithecus, which is notable for several interesting features: it had an elongated muzzle like a baboon, and the ankle joints resembled those of Australopithecus suggesting that it potentially spent time walking bipedally. Typical living macaques are mostly confined to Asia, however the Barbary macaque Macaca sylvanus of North Africa is a notable outlier. During the Pliocene and Pleistocene macaques also ranged further north into Europe. One isolated form, M. majori was left stranded on the Mediterranean island of Sardinia during the Early Pleistocene, where it underwent shrinking in body size over time.