First record of a large Callixylon trunk from the late Devonian of Gondwana

A 5 m long permineralized trunk from the Upper Kellwasser member of southern Morocco represents the first record of a large trunk of an identifiable species of Callixylon, C. erianum, from Gondwana. This occurrence constitutes the most reliable evidence based on plant megafossils for a floral connection between Laurussia and Gondwana in late Devonian times and for a proximity of these continents in Famennian times. The potential of this trunk for studies of the architecture and growth patterns of the earliest trees with a gymnospermous type of arborescent habit is discussed.