Glossopterid Plant Remains in Permineralization: What Do They Tell Us?

We describe an anatomically preserved glossopterid shoot from the Upper Permian strata of the Bowen Basin of Queensland, Australia. The specimen was sectioned obliquely through the distal part of the axis, which is represented by a thin region of secondary tissues. A series of helically arranged vegetative leaves are borne on the axis. Some of the inner leaves are attached to several small megasporophylls bearing tiny ovules. Megasporophylls are attached adaxially to Glossopteris homevalensis vegetative leaves, and ovules are attached adaxially to the megasporophyll, such that adaxial surfaces of vegetative and fertile leaves face one another during development. Together, each of these leaves with their attached megasporophylls compose the ovulate reproductive structures of the plant. This ovulate structure is compared with other known permineralized forms from Australia and Antarctica, further underscoring the diversity of glossopterid reproductive structures, which are important for reconstructing the evolutionary diversification of the group.