Maia Bukhsianidze

Georgian National Museum, Tbilisi · S. Janashia Museum of Georgia, natural history department

The project is initiated by the discovery in 2012 of a primate mandible at the Sarmatian/Meotian transition in Chachuna, a Miocene site in the Iori valley by the Georgian National Museum (unpublished). It concerns the first record of a colobine, an old world monkey, in the Southern Caucasus and possibly the oldest colobine in Eurasia. The new Georgian occurrence derives 50-60 km east of Udabno where the last Eurasian dryopithecine (Udabnopithecus garedziensis) was found, that dates to the earliest Meotian (8.0-8.5 Ma). The aim is to document the exact timing and environmental and biotic context of the Late Miocene South Caucasian primate record in order to clarify two hypotheses: (H1) dryopithecines and colobines coexisted in the southern Caucasus, or (H2) they replaced each other as part of a general faunal turnover due to environmental change in Western Eurasia at the end of Miocene, known as the Vallesian Crisis (ca. 8.7 Ma). The possibility of coexisting dryopithecine and colobine monkeys in the southern Caucasus would challenge existing views on the out of Africa migration of cercopithecids. Clarification of the Chachuna colobine relationship with other Late Neogene Eurasian and African species will shed light on the Eurasian cercopithecid evolutionary history. Our multidisciplinary approach of depositional environments, paleobotanical and fossil faunal remains within a well resolved stratigraphic context of the two primate bearing sites in the Iori valley (Udabno and Chachuna) will shed light on the dynamics of paleoenvironmental changes in the South Caucasus at times of the turnover from dryopithecines and colobines.

The aim is to document the exact timing and environmental and biotic context of the Late Miocene South Caucasian primate record.