A Novel Gymnosperm Wood from the Lopingian (Late Permian) in Zhangzi, Shanxi, North China and Its Paleoecological and Paleogeographic Implications

The Permian-Triassic transition saw extreme climatic changes that severely impacted the terrestrial ecosystem. Fossil plants, particularly fossil woods, are sensitive to climatic changes, and they, therefore, are unique materials revealing extreme environmental and climatic changes on land at that time. Abundant conifer woods were discovered in the Lopingian (Late Permian) strata of the Sunjiagou Formation in Shanxi Province, North China. The newly finding permineralized woods record the unique landscape of Lopingian North China. They represent a new conifer genus and species: Shanxiopitys zhangziensis gen. et sp. nov. Analyses of growth pattern and anatomical characteristics of the fossil woods indicate these trees grew under optimal growing conditions, and without seasonal growth cessation. However, climate signals from leaf fossils, vertebrate fossils and sedimentary evidences indicate a strongly seasonal climate in North China during the Lopingian. Thus, it is speculated that these trees likely lived in the gallery forests, which were distributed along the paleo-rivers within a seasonal landscape in the central North China block during the Lopingian.