New occurrence of the Late Jurassic Xenoxylon wood in the Sichuan Basin, southern China: wood anatomy, and paleobiodiversity implications

Although a significant member of the Mesozoic xylogical flora, Xenoxylon Gothan has been widely reported from northern China, it is striking that its occurrence in southern China is rarely documented. Recently, three species of Xenoxylon have been described from the Upper Triassic and the Middle Jurassic in Guangdong, Sichuan, and Yunnan of southern China, separately. However, Xenoxylon wood has up to now never been documented in the Upper Jurassic of southern China. Here, we report new fossil wood materials from the Upper Jurassic Penglaizhen Formation in Shehong City, Sichuan Basin, southern China, with well-preserved xenoxylean radial tracheid pitting and window-like cross-field pitting. Due to a novel combination of radial tracheid pitting, cross-field pitting and ray height, a new species, Xenoxylon shehongense Xie, Wang et Tian sp. nov., is recognized here. The discovery of this new species leads to a further understanding for the yet poorly documented Xenoxylon diversity in southern China and the diversity pattern of the latiporosum-group of the genus Xenoxylon.