EARLY JURASSIC FOSSIL CYCADS FROM YIHE BASIN IN SOUTHERN JILIN PROVINCE: Paleoclimatic significance

Abundant fossil cycad leaves preserved as impression are collected from the Early Jurassic Yihe Formation in Southern Jilin Province, China. In this paper, three genera belonging to seven species are recognized based upon leaf morphology, i. e. Pterophyllum baotoum Zhang, Pterophyllum exhibens Li, Pterophyllum cf. tietzei Schenk, Pterophyllum sp., Nilssonia inouyei Yokoyama, Nilssonia orientalis Heer and Cycadolepis corrugata Zeiller. The occurrence of these species in the Early Jurassic of Southern Jilin significantly infers that they grew in an area with a warm and humid climate in the warm temperate zone close to Paleopacific Ocean.