Abstract
Global and regional environmental changes have influenced the evolutionary processes of hominoid primates, particularly during the Miocene. Recently, a new Lufengpithecus cf. lufengensis hominoid fossil with a late Miocene age of ~6.2 Ma was discovered in the Shuitangba (STB) section of the Zhaotong Basin in Yunnan on the southeast margin of the Tibetan Plateau. To understand the relationship between paleoclimate and hominoid evolution, we have studied sedimentary, clay mineralogy and geochemical proxies for the late Miocene STB section (~16 m thick; ca. 6.7–6.0 Ma). Our results show that Lufengpithecus cf. lufengensis lived in a mildly warm and humid climate in a lacustrine or swamp environment. Comparing mid to late Miocene records from hominoid sites in Yunnan, Siwalik in Pakistan, and tropical Africa we find that ecological shifts from forest to grassland in Siwalik are much later than in tropical Africa, consistent with the disappearance of hominoid fossils. However, no significant vegetation changes are found in Yunnan during the late Miocene, which we suggest is the result of uplift of the Tibetan plateau combined with the Asian monsoon geographically and climatically isolating these regions. The resultant warm and humid conditions in southeastern China offered an important refuge for Miocene hominoids.
Highlights
(STB) section in Zhaotong basin. (c) Lithological layer pictures and sketch of the 16 m thick STB section and the numbers represent the sedimentary layers. (d) A close up view of the black peaty layer to highlight the location of the L. cf. lufengensis cranium, which is shown and described in detail by Ji et al, (2013)[5]
X-ray diffraction analyses on the clay fractions (< 2 μ m) from the whole section indicate that three main clay minerals dominate the STB section, which are independent of lithology (Supplementary Fig. 1)
To explore the environmental changes associated with the appearance of L. cf. lufengensis, the section was divided into three zones from bottom to top: Zone A, B, and C (Fig. 3)
Summary
(STB) section in Zhaotong basin. (c) Lithological layer pictures and sketch of the 16 m thick STB section and the numbers represent the sedimentary layers. (d) A close up view of the black peaty layer to highlight the location of the L. cf. lufengensis cranium, which is shown and described in detail by Ji et al, (2013)[5]. Previous studies have reconstructed the paleoenvironments for Yunnan hominoids using pollen data, clay minerals, or fauna (Table 1) Both L. keiyuanensis in the Xiaolongtan Basin[14] and L. hudienensis in the Yuanmou Basin[15] were present in a warm and wet forested habitat. A predominantly forested habitat, with marginal environments consisting of bush-grassland[11], subtropical, hilly, with some dense forestry and partial transitional bushes and seasonal climate prevailed for L. hudienensis in the Yuanmou Basin[9,16]. A transitional area of mixed forest and grassland under a warm and humid climate prevailed for L. cf lufengensis in the Zhaotong Basin[19] This diverse range of habitats and climates illustrates that the relationship between environmental changes and hominoid evolution in Yunnan is complex and remains ambiguous. Due to the limited availability of high-resolution palaeoenvironmental data and systematic comparisons for these critical areas, few studies have discussed the reasons for the existence of the refuge in the southeastern margin of the Tibetan Plateau
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
