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Background: Understanding the relationship between human evolution and environmental changes is the key to lifting the veil on human origin. The hypothesis that environmental changes triggered the divergence of humans from apes (ca. 9.3–6.5 million years ago, Ma) has been poorly tested because of limited continuous environmental data from fossil localities. Lufengpithecus (12.5-6.0 Ma) found on the southeastern margin of the Tibetan Plateau (SEMTP) across the ape–human split provides a good chance for testing this hypothesis. Results: Here, we reconstructed the habitats of L. keiyuanensis (12.5–11.6 Ma) with comprehensive vegetation, climate, and potential food web data by palaeobotanical evidence, together with other multidisciplinary data and partly tested the environment-driven hypothesis by revealing the living conditions of Lufengpithecus. Conclusion: A detailed comparison of hominoids on different continents reveals their behaviour and fate divergence across the ape–human split against the background of global climate change, i.e., the stable living conditions of SEMTP not only provided a so-called 'refuge' for arboreal Lufengpithecus but also acted as a 'double-edged sword', preventing their further evolution while vegetation shifts in East Africa probably stimulated the emergence of human bipedalism, and the intense climatic changes in Europe possibly prevented those hominoids from surviving that time interval. Our findings provide interesting insight into the environmental impacts on the behavioural evolution of hominoids. [ABSTRACT FROM AUTHOR]

Morphological characteristics, as well as ultrastructure of pollen grains, chromosome numbers and karyotype analysis have been used to establish a new species of Saussurea from the Qinghai-Tibetan plateau. The new species, Saussurea pseudograminea Y. F. Wang, G. Z. Du et Y. S. Lian is easily distinguished from the similar S. graminea Dunn by having 2-3 capitula, involucre 0.7-1.2 cm in diameter, smaller pollen grains, pollen surface with larger and denser spines, achenes 4.0-5.5 mm long, 32 chromosomes, and a karyotype formula 2n = 2x = 32 = 18m + 10sm + 4st, whereas S. graminea has solitary capitula, involucre 1.2-2.0 cm in diameter, larger pollen grains, pollen surface with smaller and sparser spines, achenes 3-4 mm long, 28 chromosomes and a karyotype formula 2n = 2x = 28 = 6m + 20sm + 2st. The new species is distributed in Dianzhangou, Awanchang, and Gamaliang mountain regions of Maqu county in Gansu province. [ABSTRACT FROM AUTHOR]