Jurastrobus chenii gen. et sp. nov., a cycadalean pollen cone connected with vegetative parts from Inner Mongolia, China

摘要

Cycads used to be a dominant plant group during the Mesozoic. Many fossils of cycads or their allies have been documented, but most of them are foliages. Reproductive organs are scarce and mostly found detached from vegetative organs. Among cycad reproductive parts, ovulate cones are rather frequently seen in the fossil record, while pollen cones are rare. Here we report a cycadalean pollen cone connected with its vegetative parts from the lower Jurassic of Inner Mongolia, China. The pollen cone is situated on the apex of the stem and in the center of the leaf tuft. The pinnate leaves have lateral pinnae attached decurrently and almost perpendicularly to the rachis. The characters demonstrate a strong affinity to the extant cycads. This is the first record of cycadalean pollen cone with in situ pollen grain and organically connected with its vegetative parts, and therefore sheds new light on the morphological evolution of cycad plants.