Fossil wood of Pinus from the Pliocene of western Yunnan, China and its palaeoclimatic implications

Abstract

The Pinus (Pinaceae), widely distributed in the Northern Hemisphere, has a substantial fossil record; however, the fossil record of subgenus Strobus is comparatively modest. In this paper, we reported a new wood fossil of Pinus longlingensis sp. nov., collected from the Upper Pliocene Mangbang Formation in Longling, western Yunnan Province, China. Comparative analyses of the anatomical features of the current specimen with both extant and fossil representatives of this genus assign it to the subgenus Strobus, section Quinquefoliae, subsection Strobus. The quantitative growth-ring analyses of Pinus longlingensis indicate that it was evergreen. Furthermore, the species predominantly grew under a stable and favorable environmental condition, with short-term seasonal climate fluctuations. This investigation augments the Cenozoic wood fossil records of western Yunnan and furnishes newanatomical evidence that helps understand the climatic and environmental changes of the Late Pliocene in this region.