Temporal range: Late Miocene–Late Pliocene
|An artist's illustration of Mesopithecus pentelici|
Mesopithecus (middle ape) is believed to be the ancestor of today's monkeys, but also a langur. Both these animals are agile and long tailed.
Mesopithecus had an unusually long thumb, which gave it a very good ability to hold on everything. It appears to have survived the great periods of life on the ground, where it walked on all fours. Its length is estimated to be around 60 cm (2 ft) long where the fossils were found in Miocene rocks in South America.