The 82nd Annual Meeting of the American Association of Physical Anthropologists (2013)


Diminutive cercopithecine teeth from Kanapoi, Kenya, and implications for the evolution of body size and diversity in guenons

J. MICHAEL PLAVCAN1, CAROL V. WARD2 and FREDRICK K. MANTHI3.

1Department of Anthropology, University of Arkansas, Fayetteville, 2Department of Pathology and Anatomical Sciences, University of Missouri, 3Department of Earth Sciences, National Museums of Kenya

Thursday 9:30-9:45, Ballroom C Add to calendar

In 2012 a team from the West Turkana Paleontology Project of the National Museums of Kenya uncovered two small associated unworn second and third molar teeth of a primate from the Australopithecus anamensis type site at Kanapoi, dated to around 4.2 mya. These molars show typical cercopithecoid bilophodont, quadritubercular morphology. Metric and morphological comparisons reveal that they are indistinguishable from molars of the extant talapoin monkey (Miopithecus talapoin). This is the second oldest reported guenon fossil. Previously reported cercopithecine teeth from Koobi Fora, Kenya (minimally 3.4 million years ago) show similar morphology and size. Faunal and other analyses at Kanapoi suggests open woodland habitat with patches of grasslands. The specimen raises intriguing possibilities about the evolution of African guenons. Molecular phylogeny estimates place Miopithecus divergence at about 7-8 mya. If truly Miopithecus, the specimen extends the geographic range of these monkeys to East Africa in a dry, seasonal woodland habitat with open grasslands. The very small size suggests either that dwarfing occurred very early in this genus, or, if not Miopithecus, that there have been separate dwarfing events within cercopithecines. Alternatively, the specimens may suggest that primitive guenon body size was small, although this is contradicted by the fact that older fossil guenon teeth (5.4 mya) were larger. Whichever is the case, the new specimens suggest that the modern diversity in guenon body size arose early in the history of the group, and that diminutive size is not uniquely associated with current talapoin habitat.

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