中国科学院南京地质古生物研究所机构知识库

A silicified stem, Ductoagathoxylon jimsarensis Wan, Yang, Liu et Wang gen. nov. et sp. nov., is described from the Wuchiapingian (late Permian) Wutonggou Formation from the Dalongkou section, Jimsar County, Xinjiang Uygur Autonomous Region, northwestern China. It is composed of a pith, and primary and secondary xylem. The stem is characterized by a solid, heterocelluar pith with grouped secretory ducts and cells, an end- to mesarch primary xylem, and an Agathoxylon-type secondary xylem. Based on the Agathoxylon-type secondary xylem and the occurrence of secretory ducts and cells in the pith, it is suggested that Ductoagathoxylon is of a coniferous affinity. It provides additional evidence for the biodiversity of the Wuchiapingian Subangaran flora in northwestern China. Growth rings and false rings in D. jimsarensis and other previously reported fossil woods from the Wutonggou Formation in the Junggar Basin indicate both seasonal and intra-seasonal growth variations caused by environmental stress and precipitation seasonality. The fossil stem records suggest varying climatic and environmental conditions between the Dalongkou section in the northern Bogda Mountains and the Tarlong-Taodonggou sections, about 70 km to the south, in the southern Bogda Mountains during the Wuchiapingian. (C) 2017 Elsevier B.V. All rights reserved.