Evolutionary Ecology of fossil anthropoid primates in Southeast Asia

点击翻译按钮获取中文摘要

During the Cenozoic, Myanmar has been a key area for mammalian evolution, this region having seen the emergence and diversification of some of the major groups of eutherian mammals such as anthropoid primates as well as ruminant and hippopotamoid certartiodactyls. While a very rich mammalian diversity has been described from this region, very few studies have focused on paleoecological and paleoenvironmental aspects related to these mammalian communities. Thus, our project aims at characterizing the paleoecology and paleoenvironments of the Cenozoic faunas of Myanmar by using jointly approaches of isotope biogeochemistry (C, O) and 3D dental microwear texture analyses on mammalian taxa. We will focus on the world-famous primate-bearing faunas of the Pondaung and Irrawaddy Formations. They offer the best potential owing to their rich mammalian fossil record and the most challenging questions regarding the evolution of primates in the Central Basin of Myanmar during the Cenozoic in connection with environmental changes.The Pondaung Formation has yielded several fossiliferous localities dated from the late Middle Eocene (ca. 40-37 Ma), which delivered more than 50 mammalian species including creodonts, primates, cetartiodactyls, perissodactyls and rodents. Most emblematic are the anthropoid primates, the ruminants and the anthracothere cetartiodactyls, which early evolution is documented in Pondaung. Recent studies have proposed that the Pondaung mammalian communities evolved in a seasonal wetlands landscape under a seasonal climate perhaps representing the earliest evidence of the Asian monsoon. Our study on the Pondaung mammals will allow:- to characterize the environments of the Pondaung primates and test the hypothesis of seasonal wetlands- to analyze the ecological structure of the fauna and especially characterize the niche-partitioning among Pondaung mostly dentally poorly-specialized herbivores- to further characterize the alleged climate seasonality so far documented on a single mammal species- to evaluate if environmental and climatic seasonality has impacted specific groups among the Pondaung community.The Miocene to Pleistocene Irrawaddy Formation has yielded a rich and diverse mammal fauna (proboscidea, rhinocerotids, giraffids, bovids...) but has only recently delivered a fauna comprising the hominoid primate Khoratpithecus, a Pongo-related fossil, from the Early Late Miocene. We will study this unique fauna in order to:- reconstruct the paleoenvironements in which Khoratpithecus evolved by the study if its associated fauna- test the putative presence of C4 plants in the early late Miocene of Myanmar.- investigate the niche-partitioning between the diversified herbivores of the fauna- compare the environments of Myanmar Khoratpithecus with those of other closely related Asian hominoids (e.g. Sivapithecus from Pakistan, Khoratpithecus from Thailand).