Skilliostrobusgen. nov., a new lycopsid cone from the Early Triassic of Australia

Abstract

Skilliostrobus australis gen. et sp. nov. is a large, ovoid, pedunculate cone present in rocks of Early Triassic age in three areas in southeastern Australia and Tasmania. The cone is heterosporous and its unisporangiate sporophylls are wedge-shaped with long horizontal limbs. Microsporophylls occur above megasporophylls in the cone and the sporangia are adaxial. Large trilete megaspores similar to the dispersed megaspore genus Horstisporites Potonié are present in the megasporangia of the cone and the microsporangia contain small monolete spores similar to the dispersed microspore genus Aratrisporites Leschik. Skilliostrobus is placed in the family Lepidodendraceae in the order Lepidodendrales. The size of the cone suggests that the parent plant was comparable in size with small arborescent Palaeozoic lycopsids and with some species of Pleuromeia. The discovery of this cone is another indication that arborescent lycopsids did not become extinct at the end of the Paleozoic.