Evolutionary Ecology of fossil anthropoid primates in Southeast Asia

在新生代，缅甸一直是哺乳动物进化的关键地区，该地区出现了一些主要的真兽哺乳动物群体，如类人猿灵长类动物、反刍动物和河马类某些趾类动物。虽然该地区哺乳动物的多样性非常丰富，但很少有研究关注与这些哺乳动物群落相关的古生态和古环境方面。因此，本项目旨在利用同位素生物地球化学（C、O）和三维牙微磨损纹理分析相结合的方法，对缅甸新生代动物群的古生态和古环境进行表征。我们将重点关注世界著名的本当和伊洛瓦底地层的灵长类动物。由于其丰富的哺乳动物化石记录和缅甸中部盆地新生代灵长类动物进化与环境变化之间的最具挑战性的问题，它们提供了最大的潜力。Pondaung组发现了几个中始新世晚期（约40-37 Ma）的化石点，其中有50多种哺乳动物，包括齿齿动物、灵长类动物、鲸趾动物、异趾动物和啮齿动物。最具代表性的是类人猿灵长类动物、反刍动物和无烟煤鲸鱼类动物，它们的早期进化在本当有记录。最近的研究提出，本当哺乳动物群落在季节性气候下的季节性湿地景观中进化，这可能是亚洲季风的最早证据。我们对本当哺乳动物的研究将允许：-表征本当灵长类动物的环境并测试季节性湿地的假设-分析动物群的生态结构，特别是表征本当主要是牙齿特异性较差的食草动物之间的生态位分配-进一步表征迄今为止在单一哺乳动物物种上记录的所谓的气候季节性-评估环境和气候季节性是否影响特定群体在本栋社区中中新世至更新世伊洛瓦底地层已经产生了丰富多样的哺乳动物动物群（鼻科、犀类、长颈鹿、牛科……），但直到最近才发现了一个动物群，其中包括来自晚中新世早期的类人猿灵长类Khoratpithecus，这是一种与庞戈有关的化石。我们将对这一独特的动物群进行研究，目的是：通过对相关动物群的研究，重建Khoratpithecus进化的古环境，验证缅甸中新世晚期早期存在C4植物的假设。-调查不同食草动物之间的生态位划分-比较缅甸Khoratpithecus与其他密切相关的亚洲人科动物（例如巴基斯坦的Sivapithecus，泰国的Khoratpithecus）的环境。

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).