| Abstract: | A new genus of fossil Cycads, Yixianophyllum gen. nov., is reported here. The specimens were collected from the southern hill of Jinjiagou village, Toudaohezi Town, Yixian County, western Liaoning Province, China. The fossil plant-bearing bed belongs to the lower part, the Zhuanchengzi bed, of the Upper Jurassic Yixian Formation (Yixianian). The new genus in leaf shape, venation and epidermal structure shows a transitional form between Mesozoic Cycads (Ctenis, Nilssonia) and modern Cycads (Stangeria and Encephalartos). Since the features of these specimens differ from any known genera of Cycads, a new generic name Yixianophyllum is proposed for these leaves. Typical species, Yixianophyllum jinjiagouense gen. et sp. nov. is described here. A supposed evolutionary tendency of Cycadean leaf-forms with Taeniopteris-type is discussed. |
