Primate de la fin de l'Eocène - Thailande, Province de Krabi.

Oldest primate fossils found 

7 janv. 2010 - Writer: Apinya Wipatayotin (Bangkok Post)

Archaeologists have confirmed fossils of the world's oldest primate, which roamed the earth about 35 million years ago, have been found in a deserted coal mine in the southern province of Krabi.
The fossils, discovered by Mineral Resources Department archaeologists 14 years ago, were named Siamopithecus eocaenus.
Confirmation of the age of the fossils was published in the scientific journal Anatomical Record in November.
Yaowalak Chaimanee, the department's senior fossil expert and a member of the archaeological team, said the discovery was the best evidence yet that primates originated in Asia and not Africa.
The oldest primate fossil found in Africa is 32 million years old, she said.
The fossils found at the old mine in Nua Khlong district include lower right molars and upper left and right molars attached to the eye bone. "These are the most perfect pieces of primate fossil we've found in the country so far," she said.
The Thai archaeologists have worked closely with experts from France and Switzerland to study the fossils and concluded the primate was around the same size as a gibbon and weighed about 7kg.
Mrs Yaowalak's team earlier found pieces of upper and lower molars and a few teeth of Siamopithecus eocaenus, also known as the Siam Ape, at the same site in 1995, but they are not as complete as the ones found in 1996.
The Siam Ape, which is of the Amphipithecidae family, was recorded in Nature magazine in 1997 as the world's newest primate species.

The Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology
The Face of Siamopithecus: New Geometric-Morphometric Evidence for Its Anthropoid Status
Volume 292 Issue 11, Pages 1734 - 1744
Published Online: 28 Aug 2009

Abstract
Amphipithecids assume a key position in early primate evolution in Asia. Here we report on new maxillofacial and associated mandibular remains of Siamopithecus eocaenus, an amphipithecid primate from the Late Eocene of Krabi (Thailand) that currently represents the most complete specimen belonging to this group. We used synchrotron microtomography and techniques of virtual reconstruction to recover the three-dimensional morphology of the specimen. Geometric-morphometric analysis of the reconstructed specimen within a comparative sample of recent and fossil primates clearly associates Siamopithecus with the anthropoids. Like modern anthropoids, Siamopithecus displays a relatively short face and highly convergent and frontated orbits, the lower rim of which lies well above the alveolar plane. The cooccurrence of spatially correlated anthropoid features and classical anthropoid dental characters in one individual represents a strong argument to support the anthropoid status of Siamopithecus. It is, thus, highly unlikely that amphipithecids are specialized adapiforms exhibiting complete convergence with anthropoids.

Anat Rec, 2009. © 2009 Wiley-Liss, Inc.

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A computer image of the jaw and teeth of the oldest primate.