New investigations on Cretaceous woods from the Jiaolai Basin, Shandong Province and their palaeoclimate relevance

The Jiaolai Basin of China is the southernmost edge of the distribution of the northern Jehol Biota and an important area which bears both the northern and southern palaeogeographical fauna representative species. The Laiyang flora in the Jiaolai Basin is located in the transitional region between the Early Cretaceous southern and northern flora of China. Currently, research on the plants in the transitional region between the northern and southern flora are relatively weak. Our study of specimens has enriched our understanding of the floral landscape in the transitional region between the north and south flora. Cretaceous wood fossils are well preserved in China and 66 species of 29 genera have been reported up to now, which are widely distributed in China. However, in the Cretaceous Shandong Province, there are few records of wood fossils. So far, only one genus and two species have been reported. In this paper a new material of fossil wood is described from the Early Cretaceous Zhifengzhuang Formation of Laiyang Group in Jingzhi area of Anqiu City, Jiaolai Basin, Shandong Province. The present specimen has uniseriate to triseriate pits on the radial walls of tracheids, taxodioid cross-field pitting and other characters. This discovery contributes to a better understanding of fossil wood diversity in Jiaolai Basin during the Cretaceous. Through the well preserved growth rings of the specimens, it can be inferred that the environmental paleoclimate of the Early Cretaceous in Shandong Province was generally arid, with some areas being humid.